A case of giant anastomosing hemangioma of the kidney with extramedullary hematopoiesis: A great mimicker.

Anastomosing hemangioma (AH) are rare mesenchymal neoplasms affecting kidney with about 50 cases reported in English literature. In general, they are accidentally detected during examination or imaging done for nonspecific symptoms or wellness check-up. There are no key diagnostic features on the imaging modalities. The most common preoperative diagnosis has been a malignant primary renal carcinoma. Surgical resection remains the mainstay of treatment and of choice in symptomatic lesions. We are presenting a rare case of giant AH of the kidney mimicking a renal cell carcinoma on imaging. The lesions are characterized by anastomosing sinusoidal-like vascular spaces lined by banal endothelial cells with occasional hobnail morphology and associated with extramedullary hematopoiesis. The treatment of choice could be a conservative approach in small and asymptomatic lesions and patients with pre-existing renal dysfunction; hence, this entity should be in the differential of vascular renal neoplasms considering its proclivity to the urogenital tract. This is the first case in Indian literature to the best of our knowledge.

Merkel cell carcinoma with seborrheic keratosis: A unique association.

Merkel cell carcinoma (MCC) is a rare, clinically aggressive neuroendocrine carcinoma of the skin; MCC is 40 times less common as compared to melanoma. The most frequently reported sites have been the head and neck, extremities, and trunk. Potential mimics include malignant melanoma, lymphoma, or metastatic small cell (neuroendocrine) carcinomas. Histopathology of MCC resembles small cell carcinoma both morphologically and on IHC. The possible cell of origin was proposed as the Merkel cell, which functions as a mechanoreceptor. It has a high chance of local recurrence, regional and distant spread. In recent times, Merkel cell polyomavirus has been implicated as the causative agent for this tumor. The same agent has a reported etiologic association with other skin lesions, including seborrheic keratosis.