Metastatic basal cell carcinoma: a case report and review of current literature.

Abstract

Basal cell carcinoma (BCC) is the most common human malignancy, yet progression to metastatic disease (mBCC) is extremely rare, with a reported incidence of 0.0028% to 0.55%. The clinical course of mBCC is somewhat difficult to characterise. The historical literature suggests a very poor prognosis, while more recent data excluding basosquamous carcinoma proposed a mean survival of 7.3 years. While there is no standard treatment protocol for mBCC, the mainstay of treatment is surgical resection of the lesion if amenable, combined with chemotherapy or radiotherapy. We present the case of a 90-year-old male patient with an extensive history of multiple basal cell carcinomas who presented with a 6-month history of an enlarging subcutaneous nodule of the anterior arm, subsequently found to be an in-transit BCC tumour deposit on excisional biopsy. Eventually an ipsilateral axillary clearance was performed, with nodal sections revealing nests of neoplastic basaloid cells with peripheral palisading consistent with mBCC, a diagnosis supported by immunohistochemistry. The patient was subsequently referred for radiotherapy. We provide a review of the current literature to further characterise the behaviour, histopathology, and diagnostic pitfalls of this rare entity.