Superficially Invasive Vulvar Squamous Cell Carcinoma: A 37-Year-Long Experience of a Tertiary Referral Center

SIMPLE SUMMARY: Superficially invasive vulvar squamous cell carcinoma (SISCCA) is a rare subgroup of vulvar squamous cell carcinoma with good prognosis and low risk of groin metastasis, however experience reported in the literature is limited. The aim of our retrospective study is to present a large series of SISCCAs and analyze prognostic outcomes. We also described a case of SISCCA from our series with vulvar recurrence and groin metastasis, together with a literature review of this issue. Overall, SISCCA have a good prognosis, irrespective of type of surgical treatment, pathological characteristics, and status of surgical margins. However, patients should enter in accurate long term follow-up, in particular for younger patients and in case of small tumors, as recurrence or re-occurrence may occur even after many years after diagnosis. ABSTRACT: Superficially, invasive vulvar squamous cell carcinoma (SISCCA) (FIGO stage IA) is a rare subset of vulvar cancer defined as a single lesion measuring ≤2 cm with a depth of invasion of ≤1.0 mm. This is a retrospective study performed on 48 patients with SISCCA, surgically treated between 1981 and 2018 at the S. Anna Hospital, University of Turin, to evaluate pathological characteristics and prognosis of these tumors. Ten patients (21%) recurred: seven (14%) as SISCCA and three (7%) as deeply invasive carcinoma. One case with perineural invasion and groin node metastasis at recurrence. No patient had groin lymph node metastases at initial diagnosis. Site of SISCCA, type of surgery, status of surgical margins, and histopathological features did not differ between recurrent and non-recurrent patients. We observed a non-significant trend towards an increase of recurrences in younger women (median age: 63 years vs. 70 years, p = 0.09), while, surprisingly, smaller tumors (<12 mm) were significantly related to tumor relapse (p = 0.03). Overall, SISCCA has a good long-term prognosis, regardless of the pathological characteristics and the type of surgical treatment. We recommend close follow-up, especially for younger patients and for small tumors, due to the possibility of recurrence or re-occurrence even after years.