Pathology of Combined Nevus - Dr Sampurna Roy MD

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Pathology of Combined Nevus:

"Two or more different types of Melanocytic Nevi in a single lesion."

This lesion is characterised by a combination of Acquired Melanocytic Nevus or Spitz nevus with Blue Nevus or Congenital Nevus.

Clinically, combined nevi present as well circumscribed hyperpigmented spots surrounded by less pigmented areas.

Microscopic features:

In Combined Nevus there is a mixed cellular pattern.

Histologically, two pigmented melanocytic lesions are usually present in distinct areas or may be closely intermingled.

These lesions may simulate melanoma by being asymmetrical and displaying prominent irregular pigmentation.

Microscopically, one variant reveals epithelioid and spindle cells of Spitz nevus together with dysplastic nevus.

In another variant there are small melanocytes with large balloon cells, simulating balloon cell melanoma.

It is not at all uncommon to see a very small component of non-blue nevus in a cellular blue nevus or deep penetrating nevus.

Unlike melanoma, there is no evidence of pagetoid intraepidermal spread.