Microinvasive squamous carcinoma of the vulva

The clinico-pathologic aspects of 15 cases of microinvasive squamous cell carcinoma of the vulva are analyzed and the literature on this subject is reviewed. Three patients in this group and 12.5% of the 279 reported cases, all with 5 mm or less depth of invasion, have had lymph node metastases and/or recurrences or have ultimately died of their disease. The prognostic value of lymphatic/vascular permeation, the degree of cellular anaplasia, the pattern as well as the depth of invasion, all have been alluded to, and the latter is popularized. It is noted, however, that the arbitrarily chosen 3 or 5 mm depth of invasion alone does not allow for consistent identification of individuals with a negligible risk for groin lymph node metastasis. There is indeed documentation of nodal metastases in 20 of 178 (11%) of the reported cases with 1-3.5 mm invasion. It is suggested that the level of invasion, as determined by Clark's classification, which provides a histologic reference point, may correlate better with the incidence of groin nodal metastasis, and its use may allow for individualized therapy and eventually aid in identifying cases of microinvasive carcinoma of the vulva that could safely be treated without lymphadenectomy.