47 year old female with a darkly pigmented buttock lesion
- Discovered in the early 1970's by Reed, many believe this nevus is closely related to Spitz nevus, and there is some morphologic overlap
- Often clinically mistaken for melanoma because the lesions arise rapidly and are deeply pigmented (contrast with Spitz nevus which is rarely mistaken for melanoma)
-predilection for the lower extremities, especially thigh of young women
Morphologically:
1) symmetric and circumscribed on lower power
2) vertically oriented nests of pigmented spindle cells
3) common to see Kamino bodies and background epidermal hyperplasia
4) Unlike Spitz, many of the melanocytes blend with adjacent keratinocytes, and there is not as much pagetoid scatter or involvement of the deep dermis
- Complete excision is curative