Case 5 Female, 48 years. Changing papule, backShow diagnosis & comments
Superficial spreading melanoma with partial regression
When investigating an excisional biopsy of a melanocytic lesion, it is a good idea to start at the very edge of the specimen: there, a small stretch of normal skin is generally present, so that it is immediately clear, what the appearance of the skin of that body site and in this patient looks like. Features such as epidermal atrophy or hyperplasia, hyperkeratosis, dermal fibrosis &c are then more easily identified within the lesion. This is important, for subtle but important changes may otherwise remain unnoticed.
This small focus of melanoma is associated with a stretch of adjacent superficial dermal fibrosis, that in all likelihood represents an area of partial regression of this melanoma. Because it reaches the excisional edge, this melanoma is incompletely excised.
Partical regression is prognostically unfavourable in thin melanoma, such as this one, and occurs most commonly in melanomas of the trunk (particularly the back).