Basosquamous Carcinoma Arising from the Vulva: A Case Report.

Introduction: Basosquamous carcinoma (BSC) of the vulva is an uncommon tumor that primarily consists of basal cell carcinoma with squamous differentiation. Also known as metatypical basal cell carcinoma, BSC is typically classified as a skin cancer and represents only 2% of non-melanoma skin malignancies. This type of carcinoma has a poorer prognosis than basal cell carcinoma due to its increased local aggressiveness and metastatic potential.

Case presentation: We present the case of a 59-year-old woman with a 3-year history of a slow-growing and painful vulvar lesion. Clinical examination revealed a 35-mm nodular, ulcerating, and non-pigmented lesion located on the labia majora. A biopsy confirmed the diagnosis of BSC, and staging assessments indicated no evidence of metastasis. The patient underwent partial radical vulvectomy and sentinel lymph node biopsy, with histological analysis revealing distinct features characteristic of BSC, including basaloid cell islands and areas of significant squamous differentiation. The excision margins were tumor-free, and all six lymph nodes examined were negative for metastases. Regular surveillance for 6 months was conducted without signs of recurrence.

Conclusion: After reviewing the literature, this case represents the sixth documented instance of vulvar BSC. Compared to basal cell carcinoma, BSC has a poorer prognosis, with a higher potential for recurrences and metastases. While basal cell carcinoma is much more prevalent among vulvar and skin malignancies, recognizing the squamous differentiation component is crucial for ensuring wider margins during surgical excision.