Merkel Cell Carcinoma.

Merkel cell carcinoma is a primary neuroendocrine tumour of the skin arising from the dermis and extending into the subcutis, occurring commonly in sun-exposed areas of the head and neck of the elderly. Clinically, non-specific erythematous or violaceous firm nodules or small plaques which may be surrounded by small adjacent satellite tumours are seen. Diagnosis of Merkel cell carcinoma is difficult by light microscopy alone and need of ancillary techniques like electron microscopy and immunohistochemistry may be necessary. Treatment modalities are dependent on the stage of the disease. We report a 73-year-old male who presented with multiple nodular swellings on the right buttock, right side of the lower abdomen, and right upper thigh since 2 months. Biopsy revealed Merkel cell carcinoma and immunohistochemistry confirmed it. In order to stage the disease, an ultrasound abdomen was done which showed multiple enlarged para-aortic lymph nodes and retroperitoneal lymph nodes with necrotic centres and right-sided hydroureteronephrosis and computed tomography is advised for further co-relation. Computed tomography of the abdomen showed extensive lymphadenopathy with perinodal fat forming conglomerate masses in the para-aortic, aortocaval, retrocaval, bilateral iliac, and inguinal region encasing the aorta, vena cava, and bilateral iliac arteries; extensive soft tissue density nodules in the skin extending into the subcutaneous plane and superficial muscular plane of the gluteal region and lower abdomen; and mild hydronephrosis of the right kidney due to encasement of lower ureter by lymphadenopathy. We report a case of Merkel cell carcinoma with distant metastases with the same relevant discussion.