Occult metastasis in carcinoma of oral cavity

To determine the frequency of occult neck node metastasis in squamous cell carcinoma of oral cavity, in particular relation to the subsite and histopathological grading, and of involvement of the level of lymph nodes in the neck in oral cavity carcinoma.

Descriptive study. Place and Duration of the Study: Pakistan Institute of Medical Sciences, Islamabad and Wah Medical College, POF Hospital, Wah Cantt. from June 2000 to August 2006.

Inclusion criteria were untreated carcinoma of oral cavity, not crossing midline, having N0 neck. The tumors size more than T4 were excluded. All patients had ipsilateral type III modified radical (functional) neck dissection and lymph node groups were subjected to histopathology.

Occult metastasis were found in 12 out of 37 cases (32.4%). Metastasis in tongue carcinoma was 5/14, lower alveolar ridge carcinoma metastasized in 5/18, floor of mouth carcinoma was 2/4 and buccal mucosa carcinoma was 0/1.The percentage of occult metastasis in well-differentiated carcinoma (WDSCC), moderately differentiated carcinoma (MDSCC), and poorly differentiated carcinoma (PDSCC) were 22.2, 25% and 54.6% respectively. The levels of lymph nodes involved were level I (16.7%), level II (83.3%), level III (75.5%) and level IV (16.7%).

Oral cavity is a favourable site for metastasis to lymphatics even with small tumors. Occult metastasis is so frequent even with early carcinomas that neck should be treated with primary site. It is also important to remove level IV lymph nodes along with level I, II and III.