Pretibial metastatic basal cell carcinoma

A 72‐year‐old immunocompromised woman presented with a 6‐month history of a rapidly growing right pretibial lesion (Figure, A) and a palpable right groin lump. Excision biopsy (Figure, B) demonstrated a pretibial basal cell carcinoma (BCC) with nodular and infiltrative growth, extensive lymphovascular invasion, but no perineural invasion. Basosquamous features were not present. An ultrasound with fine needle aspirate indicated BCC metastasis to the right groin lymph nodes. Positron emission tomography (PET) scan identified no other metastasis. A right groin clearance confirmed metastatic BCC (Figure, C). The tumour cells showed diffuse positive staining with BerEP4 and were largely negative for epithelial membrane antigen.

Rates of BCC metastasis range from 0.0028% to 0.1%.1 Large tumour size (> 5 cm), ionising radiation exposure, head and neck tumour location, immunosuppression, and perineural invasion are all recognised metastatic BCC risk factors.1,2 Metastatic BCC should be considered in patients with these risk factors.