Squamous-cell carcinoma of the floor of the mouth.
Among the histologic parameters described by Jakobsson, only the stage (depth) of invasion appears to be of value in predicting lymph node metastases. Early carcinomas of the FOM examined in our institution (T1 and some T2) grew in a superficial or horizontal manner and none developed metastases or local recurrence. Larger neoplasms (some T2 and all T3 and T4) had extensive submucosal and deep soft tissue infiltration and a corresponding high frequency of regional lymph node metastases. T1 and T2 neoplasms with only superficial or microinvasion of the submucosa have little or no propensity for lymph node metastases while T2 cancers with nodular or vertical in filtration into the submucosa have a substantial frequency of metastatic disease (44%). If the biopsy sites are carefully selected, these growth patterns can be identified by the pathologist. In addition, our experience is that clinical assessment of cervical lymph nodes for the presence of metastatic disease is often erroneous. Rates of 56% false positives and 24% false negatives were observed, which were similar to rates reported in other series. Biopsy evaluation of the extent and growth pattern of the primary neoplasm is as important as physical examination in determining the type of surgery to be done and whether lymph node dissection should be performed.