1. Carcinoma of unknown primary origin
(CUP)-198
Unknown or occult primary carcinoma is the presentation of metastatic neck lymphadenopathy
without the development of a primary lesion within a subsequent five –year period.
Failure to identify an occult primary has been attributed to either spontaneous regression of the
primary tumour, autoimmune destruction, or possibly accelerated tumour progression.
The term carcinoma of unknown primary origin should be used if no evidence of primary tumour is
found after adequate clinical examination,fibreoptic endoscopy & conventional radiological
investigations. It is about 2-3% of patients with head &neck malignancy.Metastases most commonly
occur at levels II &III, squamous cells carcinoma is most common.Five years survival rate exceeding
50% ,irrespective of the management.
Isolated supraclavicular nodal involvement is almost invariably related to malignant disease arising
below the clavicles.
Diagnosis
1)History
2)Clinical examination with nasoendoscopic examination of upper GIT.
3)FNAC & in case of uncertainity ,open biopsy is necessary.
The majority of the patients presenting with levels II/III mass will have a primary tumour of
submucosa of the tongue base or tonsil.
The diagnosis of a brachial cyst in patients with over the age of 40years ,following excision to
report the presence of metastatic squamous cells carcinoma. It may be cyctic metastases from a
tongue base or tonsil carcinoma.
4)Chest x-ray to exclude primary Bronchial carcinoma.
5) CT/MRI or PET-CT fusion imaging.PET using 18-fluorodeoxyglucose is a promising disease
detection modalities because of its ability to differentiate between tissue with a high rate of
metabolism such as tumour ,inflammation or infection & tissue with a low metabolic rate like scar.
PET-CT offer greater sensitivity,selectivity, & specificity & also reduced number of false –positive
results. PET-CT prior to endoscopy & biopsy. Once the biopsy have been carried out ,PET scan need
to be delayed 6wks to prevent false result.
6) Panendoscopy with Biopsy; laryngo –pharyngo-oesophagoscopy under G/A;in the absence of an
obvious primary on endoscopy, tonsillectomy ,Tongue base biopsy,Biopsy of the postnasal space &
pyriform fossa.

2. 25% cancer found ipsilateral to the nodal metastases,10% contralateral, so bilateral tonsillectomy
preferred.
Submucosal tongue base biopsy ; wedge biopsy ,cutting deeply into the tongue base rather than just
using cupped forceps.
All these clinical examination, CT/MRI, Panendoscopy with biopsy can reveal the primary site over
40%. Diagnostic accuracy may be further enhanced by using laser –induced fluorescence endoscopy.
(enhanced by 15-38%).
Treatment of CUP
Modified neck dissection is recommened for all patients with CUP with cervical lymphadenopathy.
Post-operative selective or panmucosal radiotherapy is indicated for most patients with advanced
operable neck disease.Amifostine a radioprotecting agent to protect salivary glands.
Intensity modulated radiotherapy(IMRT) a technique for delivering tumoricidal radiation doses to
mucasal sites. (a reduction dose to sensitive major salivary glands).
Shehadeh reported a benefit in locoregional control with postoperative radiotherapy with
concurrent cisplatin (100mg per m2 given 3 wkly).