Cellular blue nevus

Deba P Sarma, MDOmaha

F 39, left buttock

Normal epidermis, infiltrating dermal tumor

Less cellular area of spindle cells in the upper dermis

Highly cellular partin the subcutis

Cellular area composed of spindle cells

Scanty melanin pigment in the cellular area of epitheliod cells

Scanty melanin pigment in the cellular area of epitheliod cells

Blue nevus: two clinical and histologic variants- Common blue nevus and cellular blue nevus.

Cellular blue nevus is rarer than common blue nevus. It is a large, solitary, 1-3 cm in size, elevated, smooth-surfaced, gray-blue-black lesion on the buttocks, sacral region, and on the dorsal hands and feet. Histologically, the tumor is a well-circumscribeddumbbell-shaped nodular mass with broader dermal part and extending into the subcutis. There is nojunctional nest. Plump spindle cells, epitheliod cells and

dendriticmelanocytes containing variable amount of melaninpigment constitute the tumor. Sometimes, pigments canbe scanty. Cellular areas are prominent in the center of thetumor and in the subcutis. There is no maturation with depth.

Tumor cells are positive with S-100, Melan-A and HMB-45.