The mental nerve, a branch of inferior alveolar nerve passes through it and supplies the chin, lower lip and buccal mucosa of incisors, canines and the premolars.
Diagram showing parts of Medial aspect mandible from anterior to posterior-
Buccal surface view of mandible showing attachment for various muscles from anterior to posterior-
Soft tissue arrangement over inner aspect of mandible showing-
Regions of neck for neck dissection along with mandibulectomy specimen depending upon Tumor involving LN/
Dotted line depicts - to be resected portion in anterior mandibulectomy.
These are the twotypes of rim mandibulectomy.
“Because head and neck specimens often contain bone or teeth, technical equipment to allow the slicing of specimens should be available” which includes-
The resected mandible bone is a technically challenging specimen, especially if there is an attached tumor. The main difficulty is in presenting relationship between the bone and the soft tissue. There fore the orientation is must.
For example,the muscle is thought of as a cube. You should therefore take perpendicular margins from each face of the cube. As illustrated, these include the anterior, posterior, medial, lateral, and inferior surfaces. The sixth surface, the superior surface, is covered by the epithelium, so this is not a margin. Similarly, the epithelium is thought of as a square sheet. Take perpendicular margins from the posterior, anterior, medial, and lateral edges of this square. Finally, the bone is thought of as a cylinder.
Carnoy's solution described by Voorsmit (1981) contains 100% ethanol, chloroform and glacial acetic acid in a 6:3:1 ratio with added ferric chloride. Fixes tissue in 1-3 hrs and preserves glycogen from the tissue Depth of penetration is 1.3-1.6cm. (can penetrate bone upto 1.54cm in 5min without damage to alveolar nerve)
Grossing of mandibulectomy specimen - Dr Pranav, MGIMS
Pranav N Shirbhate
• Types of mandibulectomy
• General description
• Grossing techniques
• Histological sectioning
• Mandibulectomy is the resection of a part of
thickness of the mandible or of a segment of
• Often performed along with resection of the
primary tumor in the oral cavity especially the
buccal mucosa and gingival lesions.
• Sometimes to facilitate surgical resection as in
case of large tumors and those located more
posteriorly in the oral cavity.
When mandibular resection needed?
• Actual direct invasion to the cortex is rare.
This usually occurs via a socket, e.g. an
extraction or periodontal region disease or
from retro-molar trigone carcinoma.
• However if the tumor is fixed to the
periosteum & cortex, this in itself is
believed an indication to consider
removing the underlying cortex, it is better
to remove the adjacent bone, either the
margin if possible or segmental resection.
Types of resection
1. Composite or commando resection
2. Anterior mandibulectomy
3. Marginal mandibulectomy
4. Segmental or rim mandibulectomy
6. Total mandibulectomy
Composite or commando
• Wide excision of the main lesion in the buccal
mucosa, tongue or tonsil lying in close proximity with
mandible together with suitable mandibulectomy and
radical neck dissection where the entire specimen is
received in one block ie en block resection
(Not commonly practiced now due to morbidity and
reconstructive challenge and reserved for very
• T3/T4 tumors of buccal mucosa.
• Carcinoma tongue (anterior located, more than 2cm
• In this the anterior or middle part of the
mandible is excised along with the
resection of the primary tumor,
gingivolabial sulcus and sometimes a
portion of the lip anteriorly and a part of
the mucosa of the floor of the mouth
• This is done in the more anterior located
tumors that involve the anterior
A primary tumor, gingivolabial sulcus and portion of the lip anteriorly and a part
of the mucosa of the floor of the mouth posteriorly requiring ant
Marginal or rim mandibulectomy
• Removes a portion of the mandible
(usually the alveolus and the medial plate)
without disrupting continuity of the
bone. This is typically performed when
tumor involves the periosteum without
• Carcinoma lip with mandibular invasion.
• Carcinoma mandibular alveolus.
• Carcinoma of the buccal mucosa invading the
• Carcinoma of the floor of the mouth.
A lateral resection for a lesion
involving the alveolus
Large submandibular node fixed to the
lower edge of the mandible, requiring
• In this a portion of the mandible is
resected along with the primary tumor
disrupting the condyl to condyl continuity.
• This is performed when tumor invades
bone ie tumor beyond periosteum.
1. Carcinoma involving mandible.
2. Squamous cell carcinoma of the floor of
the mouth, oral cavity, oropharynx.
3. Carcinoma of the buccal mucosa
invading the mandible.
• Done for more laterally placed lesions
where in one half of the mandible is
removed along with the tumor.
Resection in posterior segment.
• The retromolar trigone is the triangular part
of the gingival mucosa that covers the
ascending ramus of the mandible.
• As this region is particularly small, tumor in
this have already extended beyond and
spreads into adjacent structures, so some
prefer to classify growths in this area
according to their predominant site of
• A posterior segmental mandibulectomy
(along with the gingiva) with or without
removing the ramus of mandible along
with some of the part of the gingival
sulcus, buccal mucosa, anterior tonsillar
pillar is performed in this tumors.
• If the tumor extends superiorly along
the mucosa covering the ramus then
a partial upper alveolectomy
accompanies this specimen and is
known as ‘ Bite resection’.
• Sometimes a part of the tongue or
soft palate is included.
• Adequate surgical margins are key to the
successful cure of larger oral cancer.
Histologically tumor strands frequently
extend along tissue planes a centimeter or
so from the visible or palpable edge.
• A 2 to 3 cm gross margin is what most
Type of neck dissection Structures removed
Comprehensive neck dissection
1) “Classic” radical neck
All lymph-bearing tissue (levels I-V),
Spinal accessory nerve ([CN] XI),
Sternocleidomastoid muscle, and
Internal jugular vein
2) Modified radical neck
“Classical neck dissection with sparing of
one or more of the above structures
Type I CN XI spared
Type II CN XI and internal jugular vein spared
Type III (functional neck
All three structures spared (CN XI, internal
jugular vein, and sternocleidomastoid
Ie tissue from level I-V removed.
Selective neck dissection Removal of lymph-bearing tissue from:
Lateral Levels II-IV
Posterolateral Levels II-V
Supraomohyoid Levels I-III
Left sided neck dissection showing lymphatic zones,
with the exception of level Ia.
Aim of dissection
• Answer questions that will lead to an
accurate pathological diagnosis and
pathologic staging if the tumor is
• Features of interest
structures invaded by tumor
whether the margins are free
whether preoperative diagnostic
imaging has given a true picture of
tumor size and extension.
• Well maintained dissecting knife, scissors,
saws, scalpels, forceps, probe, chisel, and
• For maxillofacial specimens,
a water cooled diamond grinding
blade is mandatory –
It allow slicing without separating the soft
tissues from either bone or cartilage, and
thus enable a cut surface to be obtained
that clearly shows how the tumor
involves the relevant anatomical
• Accurate patient identification.
• Clinical history - including symptoms,
past treatment, radiological findings and
• Specific specimen identification,
including exact anatomical site.
• Any specific or special requests - should
• Fix the whole specimen in formalin
overnight in a refrigerator at temperature
• Teeth, if present should be removed
• Immersing a whole specimen in
decalcification solution only allows further
processing after a prolonged time but
leads to unacceptable loss in quality of
gross and microscopical features.
Orientation of specimen
• The size and type or resection for a
mandibular tumor can vary from a
small segmental resection to radical
procedures as total
• The margins are easily remembered
using the geometric shapes
visualized for each component or
can be fixed permanently by using
India ink .
• Anterior margin: bone.
• Posterior margin : bone or in case when
mandibular condyle and coronoid are
resected, then the pterygoid musculature and
adjacent soft tissue.
• The medial and lateral margins will generally
consist of oral cavity mucosa; however
extensive tumor may invade soft tissue(both
floor of mouth and lateral) and even skin.
• Resection of the entire body of the mandible
involves resection of the following muscles from
anterior to posterior.
• On the lateral border : mentalis, depressor
labii inferioris, trangularis , depressor anguli
oris, platysma, buccinators and masseter.
• On the medial : genioglossus, genohyoid,
ant. belly of the digastrics, mylohoid, medial
pterigoid and superior pharyngeal
• Mandibular specimens are sawed
perpendicular to the long axis of the
• In the case of intraosseous lesions, record
whether the lesion has caused expansion
and/or attenuation of adjacent cortical
bone or whether the tumour perforates the
• In squamous cell carcinoma of the oral
mucosa, one should assess the relation
between the tumour and the underlying
mandibular bone, which may be resorbed
away over a broad front or show diffuse
penetration into the bone marrow
Scheme indicating the various ways in which a gingival
cancer may involve the underlying mandibular bone.
(A) Vertical resorption,
(B) horizontal resorption,
(C) diffuse growth along the periodontal
ligament space and surrounding the roots of
involved teeth, and
(D) resorption involving the periosteum only,
without bone destruction.
• Bone tumors: Serially section the
specimen with a saw at 0.5 cm intervals,
then submerge in formalin
overnight. Place the sections in
decalcification solution until they can be
cut with a sharp knife.
• Mucosa/soft tissue tumors: Carefully
dissect the soft tissue off the bone,
maintaining its orientation and avoiding
PROCEDURE & DESCRIPTION
First orient the specimen.
Describe the type of resection.
Confirm the side and type of
Measure the length of the mandible along
the alveolar border.
Record the number of teeth and there appearance.
Sometimes a skin flap is resected in tumors
that have spread to the overlying skin.
Measure this skin flap and describe whether
involved or free of tumor.
Locate the tumor and describe as:
• Site of the tumor (alveolar border,
gingivobuccal sulcus, buccal mucosa)
• Size of the tumor (three dimensional, two
dimentional if ulcer or plaque)
• Colour of the tumor.
• Appearance of the tumor (ulcerative,
proliferative, papillary, verrucous, plaque
• Edges of the tumor.
• Invasion into the bone (on gross).
• Cut surface appearance.
• Note the distance of the mucosal cut
margins from the tumor.
• Paint the mucosal and soft tissue surgical
margins with India ink. Either blot dry or fix
further in formalin.
• The application of indelible(permanent) ink as an
aid to recognizing specimen margins on
histologic slides is vital for margin assessment.
• Multiple colour may be necessary to identify
specific margins for ressection.
• The ink is fixed to the tissue by modrant like 95%
ethyl alcohol, 10% glacial acetic acid.
• Ink must be completely dried before sectioning to
prevent ink tracking, seepage creating false
• For mucosal and soft tissue tumors
separate the soft tissue from the mandible
with a scalpel.
• The direction of the dissection should be
from the inferior to superior and from the
posterior to anterior aspect.
• The depth of invasion into the submucosal
tissue, adjacent soft tissue and skin should
• Comment on the non-neoplastic mucosa as
the presence of leukoplakia or any other
• The bone is then fixed in special
vise for cutting the mandible and a
3mm section of the bone with
underlying tumor is taken. Mention
the appearance of the bone on
gross section. Bone sections are
submitted for decalcification.
• If the lesion is in the alveolus the
underlying bone should be
• If the specimen includes a radical neck
dissection then lymph should be searched
while the specimen is fresh. Avoid crushing
the nodes by rough palpation.
• Fixed overnight in formalin or Carnoy’s
solution and search for nodes next day.
• Described as:
1. Number of nodes in each group.
2. Size of the largest node in each group.
3. Appearance on gross examination and
obvious involvement by the tumor.
4. Cut section appearance.
Sections for histology
1. Tumor with its deepest extent(3-5
2. Non-neoplastic mucosa.
3. Mucosal surgical cut margins- medial,
lateral, anterior and posterior. (or can
go clock wise manner)
4. Soft tissue surgical margins.
5. Bone surgical margins.
• In anterior mandibulectomy especially take
a section to demonstrate the depth of
infiltration into the muscle.
• Cut margins :
Mucosal : anterior,
right anterolateral and posterolateral,
left anterolateral and posterolateral.
• A glossectomy and b/l supraomohoid node
dissection may accompany the removal of
6. Lymph nodes
- all lymphnodes dissected should be
submitted for histology.
- small nodes upto 3mm in thickness are
submitted in toto.
- large nodes are bisected and if
necessary further sectioned into 2-3 mm
7. Sections of the bone if grossly involved or
8. Representative sections from nerve and
vein, if present , as in RND.
• Although every case does not require
significant diagnostic answers, if a
standard technique is not applied in all
routine situations, a challenging case will
become a failure.
The employment of appropriate tools
and technique makes mandible
processing, though not always easy, a
• Rosai Ackerman : Textbook of surgical
• Complex head and neck specimens and neck
dissections. How to handle them.P J Slootweg
• Manual of grossing: Tata memorial hospital.
• B. D Chaurasia, Text book of Anatomy, 4th