1. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice
2 HEAD AND NECK 2 PAROTID MASS — 1
2 PAROTID MASS
Ashok R. Shaha, M.D., F.A.C.S.
Approach to Evaluation of a Parotid Mass
There are three major salivary glands in the human body—the Nonneoplastic The causes of nonneoplastic masses include
parotid gland, the submandibular gland, and the sublingual congenital, granulomatous, infectious or inflammatory, and non-
gland—of which the parotid gland is the largest. In addition, there inflammatory conditions. Some congenital lesions (e.g., heman-
are approximately 600 to 800 minor salivary glands distributed gioma or vascular malformation) present as a vague swelling in the
throughout the entire upper aerodigestive tract, starting from the parotid region that has been present since childhood. One con-
lip and extending to the lower end of the esophagus and up to the genital lesion, a first branchial cleft cyst, presents as a mass inferi-
pulmonary alveoli. Almost half of these minor salivary glands are or to the cartilaginous ear canal, with a cyst tract that can be either
on the hard palate. Accordingly, any mass on the hard palate medial or lateral to the facial nerve and may even divide the trunk
should be considered a minor salivary gland tumor until proved of the nerve. This cyst is most commonly noted in the second
otherwise.1 through fourth decades in life.
The majority of salivary gland tumors originate in the parotid Granulomatous diseases are frequently manifested by an
gland. Approximately 75% to 80% of parotid tumors are asymptomatic, gradual enlargement of a lymph node within the
benign.2,3 In the evaluation and surgical treatment of parotid gland; often, they cannot be readily distinguished from neoplasms.
tumors, it is essential to maintain awareness of the possibility of In sarcoidosis, salivary gland involvement may cause duct obstruc-
temporary or permanent facial nerve injury [see Discussion, Prin- tion, pain associated with the duct, xerostomia, or enlargement of
ciples of Facial Reanimation, below]. Because surgery necessarily the gland. The diagnosis is supported by chest x-rays that show
entails some risk of an injury to this structure or its branches, as bilateral hilar adenopathy and by elevated levels of angiotensin-
well as because most parotid masses do not give rise to significant converting enzyme (ACE).
symptoms, many patients with parotid tumors may find the As noted (see above), infectious or inflammatory diseases
prospect of surgical therapy difficult to accept. involving the parotid, unlike neoplasms, tend to give rise to pain in
their early stages. Most such inflammatory conditions begin with
diffuse enlargement of one or more salivary glands. Although
Clinical Evaluation parotitis is generally unilateral, it may be bilateral if a systemic
causative condition is involved, and other salivary glands may be
HISTORY
affected as well.The pain reported may be related to the presence
Evaluation of a parotid mass begins of a stone in the salivary duct or to diffuse obstructive parotitis.
with a good clinical history. The most Chronic parotitis may lead to recurrent infection and inflamma-
important question is, how long has the tion.When recurrent swelling of the salivary gland does occur, it is
mass been present? If local pain and directly related to eating and increased salivation.
swelling of recent onset (i.e., within the Sialadenosis is a noninflammatory, nonneoplastic condition of
past few days) are reported, infection or unknown origin that is characterized by diffuse enlargement of the
obstruction is the likely cause. If the mass has been present for a salivary gland, with no discrete mass or inflammation.
longer period (i.e., weeks to months), a neoplasm is more likely.
Unfortunately, the presentations of some nonneoplastic condi- Lymphoepithelial Lymphoepithelial lesions may be divided
tions resemble those of neoplasms, and distinguishing one type of into lymphocytic infiltrative diseases and lymphomas. In many
condition from the other can be challenging. Thus, the history cases, patients with lymphocytic infiltrative diseases (e.g., Mikulicz
should continue with further questions focusing on local or sys- disease, sicca complex, and Sjögren syndrome) have had their
temic signs and symptoms, the presence of swelling or other mass- conditions for long periods, and they may feel that they have
es in the salivary glands, and previous medical conditions (includ- always been chubby, when in fact they have had chronic enlarge-
ing skin cancer). ment of both parotid glands. In patients with Sjögren syndrome,
Classification malignant transformation to high-grade lymphoma is known to
occur. Lymphoepithelial cysts are benign cystic lesions that may
Major salivary gland masses can be classified as nonneoplastic, arise from lymph nodes or from lymphoid aggregates in the sali-
lymphoepithelial, or neoplastic.4 vary gland. These lesions may be associated with HIV infection.

2. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice
2 HEAD AND NECK 2 PAROTID MASS — 2
Approach to Evaluation
of a Parotid Mass
Patient presents with parotid mass
Obtain clinical history.
Perform physical examination of parotid region,
focusing on extent of parotid disease, localized
effects of lesion, and any motor or sensory deficits.
Diffuse enlargement is present Solitary mass is identified
Diagnosis is obvious Diagnosis is uncertain
Plan treatment (conservative Initiate further workup:
or surgical, as indicated). • Imaging (CT, MRI, ultrasonography,
sialography, ?sialoendoscopy, ?PET)
• FNA biopsy (routine use is controversial)
Lesion is benign Lesion is malignant
Treat surgically with superficial Treat surgically with superficial, total, or
parotidectomy, preserving radical parotidectomy, as necessary,
facial nerve. preserving facial nerve if possible.
If cervical lymphadenopathy is present,
consider elective neck dissection
(comprehensive or selective, as appropriate).
Provide postoperative radiotherapy for all
patients except those with T1 or T2 tumors
of low-grade histology and clear margins.

3. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice
2 HEAD AND NECK 2 PAROTID MASS — 3
Primary lymphoma of the salivary gland is uncommon, occur- The most common presentation of a parotid mass, whether
ring in fewer than 5% of patients with parotid masses.5 Suggestive benign or malignant, is an asymptomatic swelling in the preauric-
clinical features include (1) the development of a parotid mass in ular or retromandibular region. Occasionally, patients present with
a patient with a known history of malignant lymphoma, (2) the metastases to the intraparotid or periparotid lymph nodes. There
occurrence of a parotid mass in a patient with an immune disor- are approximately 17 to 20 lymph nodes in the substance of the
der (e.g., Sjögren syndrome, rheumatoid arthritis, or AIDS), (3) parotid and along its tail, and there may be a smaller number of
the presence of a parotid mass in a patient with a previous diag- lymph nodes within the deep lobe of the gland. These lymph
nosis of benign lymphoepithelial lesion, (4) the finding of multiple nodes may be directly affected by metastatic tumors originating
masses in one parotid gland or of masses in both parotid glands, from the anterior scalp or the temporal, periocular, or malar
and (5) the association of a parotid mass with multiple enlarged regions. Especially with elderly patients, it is extremely crucial to
cervical lymph nodes unilaterally or bilaterally.6 obtain a detailed history of any previously excised skin lesions,
some of which may have been squamous cell carcinomas (SCCs)
Neoplastic Neoplastic masses may be present for years with- that metastasized to the periparotid nodes. Generally, such metas-
out causing any symptoms. Benign salivary tumors are more com- tasis involves multiple superficial lymph nodes and presents as dif-
mon in younger persons, whereas malignant parotid lesions are fuse enlargement of the parotid parenchyma. With the massive
more common in the fifth and sixth decades of life.7 The classic involvement of the parotid gland, facial nerve palsy is not uncom-
presentation of a benign parotid tumor is that of an asymptomatic mon in this setting.The majority of metastases to the parotid gland
parotid mass that has been present for months to years. Benign derive from cutaneous SCC or melanoma; however, metastatic
neoplasms of the parotid include pleomorphic adenoma, basal cell spread from the lung, the breast, and the kidney also is known to
adenoma, myoepithelioma,Warthin tumor, oncocytoma, and cystad- occur.13
enoma. The observation of rapid growth in a long-standing pleo- The location of the parotid mass is a very important diagnostic
morphic adenoma is suggestive of malignant transformation. In a factor. The classic presentation of a benign mixed tumor is as a
2005 study of 94 patients with pleomorphic adenoma, malignant marblelike lesion in the parotid gland—a firm, mobile mass that
transformation to carcinoma was documented in 8.5% of cases.8 commonly originates in the superficial portion of the gland and
Rapid tumor growth, metastasis to lymph nodes, deep fixation, generally is not fixed to the deeper structures or to the skin.
and facial nerve weakness are all strongly suggestive of malignant Parotid tumors that originate in the deep lobe may present as a
disease and are indicators of a poor prognosis.9 Although pain is vague, diffuse swelling behind the angle of the mandible; more
more often experienced by patients with benign conditions, it is also often, however, they present as a swelling of the parapharyngeal
reported by some patients with infiltrative malignant tumors. In area accompanied by medial displacement of the tonsil or the soft
the latter patients, pain is another indicator of a poor prognosis.10 palate.
The presence of facial nerve palsy should raise the index of sus- Although physical examination of a parotid mass is a simple
picion for malignancy. Occasionally, patients present with classic process in itself, it should be accompanied by a thorough evalua-
Bell palsy. This condition is usually of viral origin, and most pa- tion of the head and neck that includes a detailed examination of
tients recover over time. If Bell palsy persists, however, further in- the oral cavity and the oropharyngeal, nasopharyngeal, hypopha-
vestigation is required, including imaging studies to rule out any ryngeal, and laryngopharyngeal areas. Occasionally, a tumor of the
obvious parotid lesion. Facial palsy occurring in association with oropharynx presents as cervical lymphadenopathy or as metastat-
parotitis and anterior uveitis is known as Heerfordt syndrome and ic disease in the tail of the parotid. In such cases, it may be diffi-
is often seen in patients with sarcoidosis. cult to determine whether the patient has a primary salivary gland
tumor or a metastatic lesion. The presence of any suspicious
PHYSICAL EXAMINATION
pathologic condition in the oropharynx or the base of the tongue
The physical examination should focus on the extent of the dis- is an indication for appropriate endoscopy and biopsy of the sus-
ease in the parotid, the neck, and the parapharynx; the localized pected primary site.
effects of the tumor (including trismus); and the motor or senso- Physical findings suggestive of malignancy include a large and
ry deficits resulting from neural invasion. fixed mass, facial nerve weakness, lymph node metastasis, and
The mass is palpated to determine whether it is painless or skin involvement; patients with advanced parotid malignancies
painful; whether it is soft, firm, hard, or cystic; and whether it is may present with trismus. Whereas patients with benign parotid
mobile or fixed to deep tissue or skin.The skin of the scalp, the ear, tumors rarely exhibit facial nerve weakness, approximately 12%
and the face is examined for lesions. The neck is palpated for to 15% of patients with parotid malignancies have facial nerve
adenopathy. In the oral cavity, the ducts are examined for dis- dysfunction at presentation.14 The most common causes of facial
charge or saliva after the glands are milked.The pharyngeal wall is nerve weakness in this setting are adenoid cystic carcinoma,
examined for deviation, and the jaw is examined for trismus. poorly differentiated carcinoma, and SCC. Primary SCC of the
The parotid occupies a large area, starting from the zygoma and parotid is quite rare, and a diagnosis of SCC in the gland should
extending to the upper portion of the neck and behind the lead one to suspect that a tumor has metastasized to the parotid
mandible to what is commonly called the tail of the parotid. lymph nodes. Before the diagnosis of primary SCC of the paro-
Occasionally, the parotid tissue extends behind the earlobe, in tid is made, high-grade mucoepidermoid carcinoma and metasta-
which case it may be misdiagnosed preoperatively as a nonsalivary tic SCC must be excluded.
pathologic condition. Accessory parotid tissue is present along The presence of cervical lymph node metastasis may direct
Stenson’s duct in approximately 21% of persons.11 Patients some- one’s attention to the parotid mass, though only about 20% of per-
times present with a tumor (most commonly, a benign mixed sons with parotid malignancies actually have clinically apparent
tumor) of this accessory tissue.12 Attempts to excise such masses cervical lymph node metastases at the time of initial presenta-
locally must be avoided, because of the high risk of injury to tion.10 The parotid tumors most commonly associated with
branches of the facial nerve. metastatic disease to the lymph nodes at presentation are high-

4. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice
2 HEAD AND NECK 2 PAROTID MASS — 4
grade mucoepidermoid carcinoma, poorly differentiated carcino- uate the ductal arrangements in patients with chronic sialoadeni-
ma, and SCC. Lymph node metastases may also derive from high- tis. Currently, however, sialography is rarely used, both because
grade adenocarcinomas or malignant mixed tumors. there is a significant possibility of an infectious flare-up and
Some patients are totally asymptomatic, with the only signifi- because the study actually yields only minimal information. In the
cant physical finding being a mass visible through the open mouth, early 1980s, CT sialography became popular for a time; however,
which is suggestive of either a deep-lobe parotid tumor or a para- it was quite a complicated procedure, and clinicians eventually
pharyngeal tumor.The majority of parotid tumors develop within found that the information it yielded could easily be obtained from
the superficial lobe of the parotid—not surprisingly, given that spiral (helical) CT. Occasionally, surface-coil MRI may be helpful
between 80% and 90% of the parotid tissue is superficial to the for evaluating parotid masses deriving from subcutaneous process-
facial nerve. However, a significant minority of parotid masses— es. Sialoendoscopy has generated considerable interest, especially
about 10%—are found within the deep lobe. Most deep-lobe in Europe and Germany17; however, this sophisticated technology
parotid tumors are benign, in which case surgical treatment gen- has not yet entered everyday practice. Although sialoendoscopy
erally consists of a superficial parotidectomy with dissection and may be of some value in the assessment of salivary stone disease
preservation of the facial nerve, followed by removal of the tumor. or chronic sialectasis, it is rarely performed in the United States at
Occasionally, however, malignant deep-lobe parotid tumors do present, and its eventual role in the evaluation of parotid masses
occur. Such tumors frequently involve the facial nerve, and surgi- remains to be determined.
cal treatment may require sacrifice of the facial nerve in select cir- For a classic benign mixed tumor presenting in the form of a
cumstances. Most patients who have undergone surgical treat- small nodule in the superficial lobe of the parotid gland, imaging
ment of a malignant deep-lobe tumor will require postoperative is not required.
radiation therapy. Currently, the role of positron emission tomography (PET) in
the initial evaluation of a parotid mass remains undefined. This
modality may, however, be of some value in the evaluation of sus-
Investigative Studies pected recurrent parotid cancers, lymph node metastases, or dis-
The majority of parotid masses can tant metastases.
easily be evaluated with a careful history
FINE-NEEDLE ASPIRATION BIOPSY
and a thorough physical examination.
Nevertheless, it sometimes happens that Routine use of FNA biopsy in the evaluation of a parotid mass
even after these measures have been car- [see Table 1] continues to be controversial. One reason for the
ried out, there remains some clinical controversy is that cytologic evaluation is difficult. Another is
uncertainty regarding whether the patho- that the extent of surgical treatment can easily be defined by
logic process is of parotid or of nonsali- means of the clinical assessment. The main argument against
vary origin. A number of nonsalivary tumors (e.g., neurofibromas, routine use of FNA biopsy is based on the standard approach to
lipomas, lymphadenopathies, metastatic cutaneous lesions, and most parotid masses, which is a superficial parotidectomy that
lymphomas) are known to present in the parotid region on occa- includes identification and preservation of the facial nerve.
sion. These tumors may be difficult to evaluate clinically, and fur- Nevertheless, FNA biopsy can be quite helpful, especially for the
ther diagnostic studies may therefore be required. purposes of preoperative consultation with patients regarding
the suspected pathologic process and the extent of surgical ther-
IMAGING
apy. FNA biopsy has an overall accuracy that exceeds 90%,18,19
Generally, parotid masses are imaged with either computed and it is considered a good investigational tool as long as it is
tomography or magnetic resonance imaging.15 CT is superior to used in the appropriate clinical context.
MRI for evaluation of the bony structures, whereas MRI may be In the case of a classic benign mixed tumor, which presents as
more helpful in distinguishing between inflammatory conditions a mobile, confined, superficial nodule in the parotid gland, FNA
and salivary neoplasms. CT scanning is indicated in patients with biopsy is not required for further treatment. However, in cases
diffuse enlargement of the parotid gland, tumor extension beyond where the clinical picture is not definitive and one cannot deter-
the superficial lobe, facial nerve weakness, trismus, or deep-lobe mine whether the pathologic process is of parotid origin or not,
parotid tumors that are difficult to evaluate clinically. If the parotid FNA biopsy is extremely important. Besides distinguishing be-
mass appears to be fixed to the deeper structures, it is appropriate tween benign and malignant conditions, FNA biopsy can also
to proceed with CT to evaluate the extent and parapharyngeal distinguish between salivary and nonsalivary processes [see Table
extension of the disease. MRI is indicated in patients with facial
nerve paralysis. Occasionally, it may be necessary to perform both
CT and MRI. Both imaging methods are helpful and accurate in
distinguishing deep-lobe parotid tumors from other parapharyn- Table 1 Uses of FNA Biopsy in Evaluation
geal masses. They are also useful for evaluating suspicious lymph of Parotid Mass
nodes and the periphery of the mass (specifically with respect to
determining whether the lesion is encapsulated or has irregular To identify suspected malignancy
To diagnose metastatic carcinoma
borders).
To identify suspected lymphoma
Ultrasonography can be useful for determining the location of To distinguish between salivary and nonsalivary lesions
the lesion and for guiding fine-needle aspiration (FNA) biopsy. In To facilitate conservative management of Warthin tumor or pleomorphic
the past, technetium-99m scanning was commonly employed for adenoma in a poor-risk patient
the diagnosis of oncocytoma and Warthin tumor.16 To confirm preoperatively suspected malignancy in a patient with facial
Various other diagnostic studies are available for evaluation of palsy
To evaluate bilateral tumors
parotid masses. At one time, sialography was commonly employed
to assess patients with suspected salivary stones, as well as to eval-

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2 HEAD AND NECK 2 PAROTID MASS — 5
Table 2 Salivary and Nonsalivary Pathologic Table 3 American Joint Committee on
Processes Distinguished by FNA Biopsy Cancer TNM Clinical Classification of Major
Salivary Gland Tumors
Benign
Mixed tumor
TX: Primary tumor cannot be assessed
Warthin tumor
T0: No evidence of primary tumor
Malignant
T1: Tumor ≤ 2 cm in greatest dimension without
Primary salivary gland cancer extraparenchymal extension
Salivary processes
Metastatic disease in salivary gland T2: Tumor > 2 cm but ≤ 4 cm in greatest dimen-
Cystic adenoma Primary tumor (T) sion without extraparenchymal extension
SCC T3: Tumor having extraparenchymal extension
Adenocarcinoma without seventh nerve involvement and/or >
Melanoma 4 cm but ≤ 6 cm in greatest dimension
T4: Tumor invades base of skull, seventh nerve,
Lipoma and/or > 6 cm in greatest dimension
Sebaceous cyst
NX: Regional lymph nodes cannot be assessed
Lymph node pathology
Nonsalivary processes N0: No regional lymph node metastasis
Benign melanoma
N1: Metastasis in a single ipsilateral lymph node,
Metastatic cancer ≤ 3 cm in greatest dimension
Lymphoma N2: Metastasis in a single ipsilateral lymph node,
> 3 cm but ≤ 6 cm in greatest dimension; or
in multiple ipsilateral lymph nodes, none > 6
cm in greatest dimension; or in bilateral or
2].20 A variety of different lymph node pathologies, benign contralateral lymph nodes, none > 6 cm in
parotid tumors, and even suspected malignant parotid tumors Regional lymph nodes (N) greatest dimension
can be differentiated by means of FNA biopsy. Furthermore, N2a: Metastasis in a single ipsilateral lymph
lymphoepithelial lesions of the parotid, benign mixed tumors, node > 3 cm but ≤ 6 cm in greatest
dimension
and Warthin tumors are easily diagnosed with this procedure. N2b: Metastasis in multiple ipsilateral lymph
FNA biopsy is particularly useful when a parotid mass is likely nodes, none > 6 cm in greatest
to be the result of metastasis. dimension
Occasionally, in an elderly person whose overall physical con- N2c: Metastasis in bilateral or contralateral
lymph nodes, none > 6 cm in greatest
dition is poor, a conservative approach can be taken when a dimension
Warthin tumor is diagnosed by means of FNA biopsy. Similarly, N3: Metastasis in a lymph node > 6 cm in great-
in a person with a long-standing benign mixed tumor, observa- est dimension
tion may be appropriate if the patient is not a candidate for sur- MX: Distant metastasis cannot be assessed
gical intervention and if FNA biopsy confirms that the lesion is Distant metastasis (M) M0: No distant metastasis
benign. M1: Distant metastasis
FNA biopsy findings that suggest lymphoma may help one
avoid unnecessary parotidectomy and risk to the facial nerve.
Often, it is hard to achieve a definitive diagnosis of lymphoma by Staging and Prognosis
means of FNA biopsy alone. In such cases, core biopsy or open
biopsy can be performed to establish the diagnosis. Core biopsy of For cancers of the parotid gland (as well as those of other major
a parotid mass is a difficult procedure (unless the mass is very large salivary glands), staging is accomplished by means of the familiar
and very superficial), and it is generally contraindicated on the tumor-node-metastasis (TNM) system developed by the Ameri-
grounds that it may cause bleeding or facial nerve injury. Never- can Joint Committee on Cancer (AJCC) and the International
theless, if core biopsy can be performed safely, it can be a good Union Against Cancer (UICC) [see Tables 3 and 4].23
choice in cases where lymphoma is suspected on the basis of FNA The prognostic factors in the management of parotid gland
biopsy.21 Open incisional biopsy can also be performed safely tumors must be understood in relation to the stage the disease has
when done in conjunction with continuous monitoring of the reached, the need for postoperative radiation therapy, and the
facial nerve.22 overall long-term outcome [see Table 5]. Such factors include age
Benign lymphoepithelial lesions related to HIV disease are
readily diagnosed by means of FNA biopsy, especially if they are
multiply recurrent cystic lesions in the tail of the parotid or if they Table 4 American Joint Committee on Cancer
occur bilaterally. In general, HIV-related pathology is quite easy to
Staging System for Major Salivary Gland Tumors
diagnose with FNA; HIV-infected patients with benign lym-
phoepithelial lesions may be treated by providing appropriate
Stage T N M
management of the underlying illness.
The crucial points for clinicians with respect to FNA biopsy in Stage I T1, T2 N0 M0
the setting of a parotid mass are (1) that this investigative study will
not make a definitive diagnosis of parotid malignancy and (2) that Stage II T3 N0 M0
one therefore should not make decisions about how to manage the Stage III T1, T2 N1 M0
facial nerve solely on the basis of an FNA-suggested malignant
T4 N0 M0
diagnosis. Any decisions regarding the approach to the facial nerve
T3, T4 N1 M0
should also be based on preoperative assessment of facial nerve Stage IV
Any T N2, N3 M0
function and intraoperative evaluation of the nerve in relation to Any T Any N M1
the tumor.

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2 HEAD AND NECK 2 PAROTID MASS — 6
due consideration should be given to the sacrifice and subsequent
Table 5 Prognostic Factors for Salivary reconstruction of this structure.
Gland Tumors Reconstruction of the facial nerve can be performed with a
nerve graft from the greater auricular nerve, from the sural
Age at diagnosis Facial nerve dysfunction nerve in the leg, or from the ansa hypoglossi. In view of the
Pain at presentation Perineural growth technical complexity of nerve grafting, preoperative consulta-
T stage Positive surgical margins tion with a plastic surgeon may be necessary. The functional
N stage Soft tissue invasion
results of nerve grafting vary considerably, depending on the
Skin invasion Treatment type
age of the patient, the extent of the disease, and the identifica-
tion of and appropriate anastomosis to the peripheral branches
of the facial nerve. If postoperative radiation therapy is envi-
at diagnosis, pain at presentation, TNM staging, skin invasion, sioned, its potential deleterious effects on nerve regeneration
facial nerve dysfunction, perineural growth of the primary tumor, should be kept in mind.
positive surgical margins in the final pathology report, soft tissue If the tumor involves only an isolated branch of the facial nerve,
invasion by the primary tumor, treatment type, and extranodal one may opt for selective sacrifice of that branch, along with nerve
spread of the metastatic disease in the neck. To make definitive grafting. If the tumor extends beyond the parotid gland and
decisions regarding treatment, it is necessary to analyze these involves the infratemporal fossa, the ascending ramus of the
prognostic factors critically in individual patients. An example of mandible, or the mastoid process, a much more extensive surgical
such critical analysis is the prognostic index devised by the Dutch procedure (e.g., composite resection, lateral temporal bone resec-
Head and Neck Cooperative Group for patients with parotid can- tion, or radical parotidectomy with sacrifice of the entire facial
cer.24,25 In this index, a weighted combination of the parameters of nerve) becomes necessary. Such patients invariably require post-
age, pain, tumor size, nodal stage, skin invasion, facial nerve dys- operative radiation therapy [see Radiation Therapy, below]. How-
function, perineural growth, and positive surgical margins is ever, in the majority of patients who present with an isolated paro-
employed to compute a prognostic score. The score is then used tid mass and a functioning facial nerve, every attempt should be
to assign patients to one of four groups, each of which is associat- made to preserve the nerve.26 It is rarely necessary to sacrifice a
ed with an expected recurrence-free percentage. functioning facial nerve: the only indication for doing so is a situ-
ation in which the entire tumor cannot be resected without sacri-
fice of the main trunk or the branches of the facial nerve and there
Management
is concern about leaving any gross tumor behind.
Treatment of a parotid mass depends
Intraoperative Frozen-Section Examination
on the nature and extent of the lesion [see
Table 6]. Malignant parotid masses are The role of intraoperative frozen-section examination in the
treated surgically according to established evaluation of a parotid mass, like that of FNA biopsy, is the sub-
oncologic principles [see Surgical Therapy, ject of considerable debate. Nevertheless, frozen-section examina-
below], with postoperative radiation thera- tion has been found to be useful for distinguishing salivary pro-
py added as necessary [see Radiation cesses from nonsalivary processes and benign disease from malig-
Therapy, below]. Generally, benign paro- nant disease. In 80% to 90% of cases, the findings from intraop-
tid masses are managed surgically as well, with exploration of the erative frozen-section examination correlate with the final patho-
parotid gland, evaluation of the neoplasm, and appropriate logic diagnosis.27 This study is also helpful in making a definitive
parotidectomy with identification and preservation of the facial diagnosis of Warthin tumor. If frozen-section examination shows a
nerve and its branches. In the case of a suspected benign mixed benign mixed tumor and this finding agrees with one’s clinical
tumor, enucleation is contraindicated because of the possibility of judgment, lateral superficial parotidectomy should be sufficient. If
tumor spillage, incomplete removal of the tumor, injury to the frozen-section examination shows high-grade mucoepidermoid
capsule and resultant seeding of the tumor into the parotid tissue, carcinoma, selective neck dissection may be considered (mainly
or inadvertent injury to the branches of the facial nerve. Enuclea- for staging purposes, to determine whether any of the deep jugu-
tion of such a tumor is very likely to result in local recurrence, which lar nodes are positive). If frozen-section examination provides a
invariably is much more difficult to manage than the original definitive diagnosis of malignancy, further decisions about the
lesion was and poses a high risk of injury to the facial nerve. extent of parotidectomy and possible selective neck dissection can
be made accordingly; if not, the procedure originally planned can
SURGICAL THERAPY
be performed, with any further interventions (if required) dictated
by the final pathologic diagnosis. Obviously, the decision whether
Parotidectomy with or without Facial Nerve Reconstruction
to sacrifice the facial nerve must not be based solely on whether
The minimum surgical procedure for a parotid mass is superfi- the frozen section shows a benign or a malignant process.
cial parotidectomy with identification and preservation of the
facial nerve [see 2:6 Parotidectomy]. Subtotal parotidectomy may be
required for larger tumors that involve the deep lobe of the parotid
gland; however, true total parotidectomy with preservation of the
Table 6 Principles of Treatment of Parotid Tumors
facial nerve is almost impossible, because of the parotid gland tis- Adequate local excision of tumor, based on extent of primary lesion
sues surrounding the nerve. If the tumor involves the facial nerve Preservation of facial nerve if possible
and is directly infiltrating into it, a diagnosis of malignancy should Elective neck dissection reserved for selected patients
be explored, and only if the diagnosis is confirmed should the Postoperative radiotherapy when indicated (in appropriate fields)
facial nerve be sacrificed. Preoperative facial nerve weakness gen- Prognosis determined primarily by stage and grade of tumor
erally indicates that the tumor is involving the nerve, in which case

7. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice
2 HEAD AND NECK 2 PAROTID MASS — 7
100
Table 7 Indications for Postoperative Radiation
Therapy for Parotid Cancer
75
Aggressive, highly malignant tumor
Invasion of adjacent tissues outside parotid capsule
Percent
Regional lymph node metastases
Deep-lobe cancer 50
Gross residual tumor after resection
Recurrent tumor after resection
Invasion of facial nerve by tumor
25
Neck Dissection
Overall, about 20% of patients with malignant parotid tumors 0 5 10
present with clinically detectable cervical lymphadenopathy
(cN+).10 There is wide agreement that these patients require either Time (Years)
a comprehensive or a modified neck dissection [see 2:7 Neck
Dissection], depending on the extent of the disease, but there con- Stage I, II Stage I, II with RT
tinues to be controversy regarding the management of patients
with salivary malignancies who have no clinically detectable cervi- Stage III, IV Stage III, IV with RT
cal lymphadenopathy (cN0). In one study, approximately 14% of
the patients were in cN+ status; however, approximately 12% were Figure 1 Depicted is the impact of postoperative radiation therapy
in cN0 status but presented with pathologically positive nodes (RT) on overall outcome for patients with stage I or II tumors and
(pN+).28 In view of the low frequency of occult metastasis in the patients with stage III or IV tumors.
group as a whole, the investigators generally did not recommend
routine elective treatment of the neck. They did find that certain
RADIATION THERAPY
histologic grades were associated with a higher incidence of
metastatic disease to the neck nodes: the incidence of occult Patients who present with advanced-stage (stage III or IV) dis-
metastasis was about 49% in patients with high-grade lesions, ease, a large primary tumor, close margins, perineural spread, soft
compared with 7% in those with intermediate-grade or low-grade tissue extension, facial nerve dysfunction, or cervical lymph node
lesions. In addition, the incidence of having occult metastatic dis- metastasis invariably require postoperative radiation therapy [see
ease was more than 20% in patients with tumors larger than 4 cm, Table 7].31,32 In general, this means that postoperative radiation
compared with 4% in those with smaller tumors. therapy is indicated for all patients except those with T1 or T2
The incidence of lymph node metastasis is affected not only by malignant tumors of low-grade histology and clear margins.Thus,
the size and histologic grade of the tumor but also by the histologic the decision whether to employ such therapy depends largely on
type, the primary tumor stage, the presence of facial nerve palsy, the intraoperative findings and the final pathology report. A 1990
the patient’s age, the extraparotid extension of the disease, and the analysis showed that postoperative radiation therapy had a major
degree of perilymphatic invasion.29 In a multivariate analysis, the impact on overall outcome in patients with stage III or IV tumors
variables that showed the highest correlation with the incidence of but conferred no statistically significant benefit on patients with
lymph node metastasis were the histologic type (i.e., adenocarci- stage I or II tumors [see Figure 1].33
noma, undifferentiated carcinoma, high-grade mucoepidermoid Currently, there is substantial interest in the potential role of
carcinoma, SCC, or salivary duct carcinoma) and the T stage.30 neutron therapy as a primary treatment modality for parotid
Thus, elective neck dissection may be considered in patients malignancies, especially advanced inoperable parotid cancers and
with advanced-stage primary tumors, those whose tumors are of adenoid cystic carcinomas. A group from the University of
high histologic grades, and those whose tumors are of certain spe- Washington demonstrated that neutron therapy exerted a benefi-
cific histologic types. A selective neck dissection may be performed cial effect when used as the sole treatment of advanced parotid
to remove the lymph nodes of the submandibular triangle, level II, cancers.34 Although these results are extremely promising, the
level III, and the upper part of level V for the purposes of staging.29 patients treated with this modality clearly experienced an
However, a comprehensive neck dissection that encompasses lev- increased incidence of complications. Nevertheless, for patients
els I through V may be necessary in patients who present with clin- with inoperable parotid cancer, neutron therapy may be the best
ically obvious cervical metastases. option currently available.
Discussion
Implications of Histopathologic Classification of Parotid World Health Organization.36 The most common types of parotid
Gland Cancer tumor are mucoepidermoid carcinoma, adenoid cystic carcinoma,
Alhough considerable controversy and debate continue to sur- adenocarcinoma, malignant mixed tumor, acinic cell carcinoma,
round the histopathologic classification of malignant parotid and primary SCC [see Figure 2].
tumors, most clinicians currently prefer either the classification As noted (see above), primary SCC of the parotid gland is quite
system of the Armed Forces Institute of Pathology35 or that of the rare, and most diagnoses of parotid SCC represent skin cancer

8. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice
2 HEAD AND NECK 2 PAROTID MASS — 8
cystic carcinoma is low; however, the incidence of distant metasta-
sis (especially pulmonary metastasis) appears to be high.41 It is
noteworthy that even when adenoid cystic carcinoma patients have
Other pulmonary metastases, they tend to do remarkably well. Quite
often, the metastatic disease in the lungs remains dormant for
months or even years. At present, the role of chemotherapy in the
Adenocarcinoma management of adenoid cystic carcinoma and parotid tumors is
supported only by anecdotal evidence and remains investigational.
Mucoepidermoid Principles of Facial Reanimation
Adenoid
Cystic Every surgeon who performs parotid surgery, especially surgery
for parotid cancer, should be familiar with the principles of facial
reanimation. If the facial nerve dysfunction is recognized before
Acinic the operation, appropriate arrangements may be made for plastic
Cell
surgical consultation and facial nerve grafting. If the proximal
stump of the facial nerve can be identified and the peripheral
branches detected at the time of the operation, a nerve graft repair
can be performed. The main donor nerves used in facial nerve
grafting are the greater auricular nerve, the ansa hypoglossi, and
Malignant
Mixed
the sural nerve. Of these, the greater auricular nerve is the pre-
Squamous ferred source for a graft: harvesting is relatively easy, the diameter
Figure 2 Shown are the approximate relative frequencies of the matches that of the facial nerve, and the arborization of the distal
most common types of parotid gland tumors. branches allows for a greater number of facial nerve grafts.42 The
use of loupes or a microscope helps in the placement of the 9-0
nylon stitches employed in facial nerve grafting.
that has metastasized to the periparotid lymph nodes. Primary Regeneration of the facial nerve may take 3 to 6 months.There
SCC has a high malignant potential, and radical surgical extirpa- is some controversy regarding whether postoperative radiation
tion (with preservation of the facial nerve when possible), followed therapy has a beneficial effect on functional outcome after nerve
by planned postoperative radiotherapy, is the treatment of grafting: some studies cite detrimental effects,43 whereas others
choice.37 report adequate functional outcomes.42,44 In any case, if it is feasi-
Mucoepidermoid carcinomas are best divided into low-grade, ble to perform nerve grafting, every attempt should be made to do
intermediate-grade, and high-grade tumors.38 For high-grade so. Currently, hypoglossal nerve transfer is rarely performed,45
tumors, selective node dissection may be appropriate, with due because various effective alternatives (e.g., fascia lata slings and
consideration given to postoperative radiation therapy. For the Gore-Tex slings) are available. A consultation with a facial plastic
majority of low-grade tumors—provided that they are properly surgeon may be quite helpful in the management of patients with
excised with appropriate superficial parotidectomy—postoperative total facial nerve palsy.
radiation therapy is unnecessary, because the incidence of local One of the most important considerations in addressing facial
recurrence is lower than 5%. nerve paralysis is how to prevent exposure keratopathy and other
Adenoid cystic carcinoma is a unique salivary gland tumor with ocular complications. Placement of a gold weight or a palpebral
a classic Swiss-cheese appearance under the microscope.There is a spring on the upper eyelid may be considered as a primary reha-
very high incidence of perineural spread with skip metastasis along bilitative measure aimed at preventing corneal ulceration and
the facial nerve and its branches, and the incidence rises with high- opacification.46 In the past, lateral tarsorrhaphy was commonly
er T stages.39 The incidence of local recurrence is also very high, employed for this purpose, but currently, as a consequence of the
and thus, postoperative radiation therapy should be provided to superior results obtained with the gold weight and the palpebral
patients who are at high risk for relapse (i.e., those with close or spring, it is rarely performed. Other, simpler measures for pre-
positive margins and those with perineural invasion). Such therapy venting or minimizing ocular complications include the use of arti-
appears to reduce the incidence of local recurrence.40 The inci- ficial tears and an eye patch during the day and the use of oint-
dence of cervical lymph node metastasis in patients with adenoid ment with proper taping to keep the eyelid closed at night.
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