Case 12 Female, 38 years. Red macule, skin of legShow diagnosis & comments
(Predominantly spindle-cell) Spitz naevus
(PREDOMINANTLY SPINDLE CELL) SPITZ NAEVUS
- Occurs at all ages, predominantly in children, adolescents and young adults
- Spindle cell type is the most common Spitz naevus subtype in adolescents and adults
- Spindle cell spitz naevi in that age group are most common on extremities
- May be junctional, compound or intradermal
- Junction component, if present, usually forms vertical oval nests; Confluence of nests may result in iregular masses
- Usually, there are shrinkage artifacts surrounding junctional nests, and, to a lesser extent, between cells within the same junctional nest.
- When a junctional component is present, there is usually epidermal hyperplasia
- Transepidermal elimination of nests and some ascent of solitary cells may be seen.
- Ascending cells are commonly smaller than junctional ones
- Dermal component often forms nests in the upper central part, but smaller cell groups and individually dispersed cells in the periphery, including the lesional base
- Towards the base (and lateral periphery) intradermal cells become progressively smaller
- Mitotic figures are usually uncommon and tend to be limited to upper parts of the lesion
- Overall, the architecture is regular (cellular features, arrangement of cells, type and degree of reactive changes). No abrupt changes in cell type or lesional architecture
- Pigment is often absent or scarce, but some examples contain more pigment.