Case 4 Male, 41 years. Irregular pigmented lesion, upper armShow diagnosis & comments
Superficial spreading (largely spindle cell) melanoma, with basal naevus remnant and reactive epidermal hyperplasia
The superficial atypical spindle cell proliferation is associated with epidermal hyperplasia and a basal non-atypical naevus remnant, which could inappropriately be interpreted as indicative of 'maturation' of the lesion, leading to a misdiagnosis of (spindle cell) compound naevus. Closer study makes clear that the mitotically active, actypical cell population represents a small spindle cell melanoma, associated with an underlying naevus remnant.