Basosquamous cutaneous carcinoma: a rare case study involving the perineum and review of the literature.

Basosquamous carcinoma (BSC) is a rare form of non-melanoma skin cancer with significant invasive and metastatic potential. This malignancy presents unique challenges in diagnostic and therapeutic options given its ambiguous clinical nature. While there are documented cases of BSC involving the aerodigestive tract and sun-exposed areas like the head and neck, cutaneous BSC in the gluteal and perineal regions remains quite rare. In this report, we provide an overview of the epidemiology, clinical presentation, treatment modalities, and prognosis of this disease. We describe a case of a 71-year-old female who presented for evaluation of a symptomatic right-sided cutaneous lesion in the inner gluteal and perineal region. Upfront surgical resection was pursued for both diagnostic and therapeutic purposes. Final pathology of the lesion revealed infiltrating BSC with negative margins. Although BSC typically presents in sun-exposed areas, the presentation in this patient in a non-sun-exposed area makes this presentation unusual.