Case 20 Female, 28 years. Pigmented papule, skin of backShow diagnosis & comments
Deep penetrating naevus.
This example shows a conspicuous micronodular architecture.
DEEP PENETRATING NAEVUS
- Pigmented papule, usually smaller than 1 cm, wide age range, many body sites
- Enlarged naevoid melanocytes with usually lightly (or moderately pigmented cyoplasm and pump, sometimes somewhat pleomorphic and anisochromaticnuclei, at all levels of the lesion (i.e., no so-called 'maturation')
- Cells cluster together in small nests and strands
- No bulky cell masses (as in some thick melanomas consisting of large cells)
- Dermal penetration often centered around a hair follicle, resulting in a wedge shape.
- No destruction or gross distorsion of involved skin
- Mitotic figures commonly present and may be found at all levels of the lesion, but they are not numerous
- Some lymphocytic inflammatory infiltrates may be present; no plasmocellular infiltrates