Case 23 Female, 1 ½ years. Pigmented lesion, skin of upper legShow diagnosis & comments
Pigmented spindle cell naevus (Reed naevus); ascent and intra-adnexal spread
Spread of naevi, including Spitz naevus and its variants, within and immediately surrounding skin adnexae, is occasionally striking. When encountered in chronically sun-damagedd skin, intra-adnexal spread should lead one to consider lentigo maliga (or lentigo maligna melanoma) but of course, such a consideration does not apply with this histology and in this clinical setting.
PIGMENTED SPINDLE CELL NAEVUS (REED NAEVUS)
- Spitz naevus variant occurring predominantly in children, adolescents and young adults
- Usually compact and densely cellular lesion
- Large spindle cells, often containing much melanin pigment, but some examples are poorly pigmented
- Junctional component forms nests, often confluent, resulting in irregular masses
- Reactive epidermal hyperplasia
- Transepidermal elimination of nests is common
- Ascent of solitary cells is commonly present
- Mitotic activity is commonly identified. Abnormal mitotic figures are not a feature.
- Dermal component is commonly rather cellular and compact, but there is no deep extenstion into the dermis.
- Often melanophages and round-cell inflammatory infiltrate
- Overall, this densely cellular lesion has a regular appearance, devoid of sudden changes in cell type, architecture or reactive epidermal or dermal changes