Case for diagnosis

an 80-year-old caucasian male patient was referred for evaluation of a rapidly growing, asymptomatic, erythematous nodule measuring 2 cm in diameter on his left cheek. the lesion had been present for four months. dermoscopy revealed a homogeneous pink background with polymorphous telangiectatic vessels. histopathology showed tumors in the deep dermis and subcutis composed of round cells with scant cytoplasm. immunohistochemical staining was positive for ck20 confirming the diagnosis of merkel cell carcinoma.