1. Cellular blue nevus Deba P Sarma, MD Omaha

2. F 39, left buttock Normal epidermis, infiltrating dermal tumor

3. Less cellular area of spindle cells in the upper dermis

4. Highly cellular part in the subcutis

5. Cellular area composed of spindle cells

6. Scanty melanin pigment in the cellular area of epitheliod cells

8. Blue nevus: two clinical and histologic variants- Blue nevus: two clinical and histologic variants- Common blue nevus and cellular blue nevus. Common blue nevus and cellular blue nevus. Cellular blue nevus is rarer than common blue nevus. Cellular blue nevus is rarer than common blue nevus. It is a large, solitary, 1-3 cm in size, elevated, It is a large, solitary, 1-3 cm in size, elevated, smooth-surfaced, gray-blue-black lesion on the smooth-surfaced, gray-blue-black lesion on the buttocks, sacral region, and on the dorsal hands and buttocks, sacral region, and on the dorsal hands and feet. feet. Histologically, the tumor is a well-circumscribed dumbbell-shaped nodular mass with broader dermal part and extending into the subcutis. There is no junctional nest. Plump spindle cells, epitheliod cells and dendritic melanocytes containing variable amount of melanin pigment constitute the tumor. Sometimes, pigments can be scanty. Cellular areas are prominent in the center of the tumor and in the subcutis. There is no maturation with depth. Tumor cells are positive with S-100, Melan-A and HMB-45.