Talk:Melanocytic lesions

Intradermal congenital-type nevus

Microscopic description

The sections show hair-bearing skin with epithelioid, dermal melanocytes, with occasional pigmentation, small or indistinct nucleoli and occasional nuclear inclusions, that are arranged in small nests. The lesional melanocytes are separated from the overlying epidermis in the plane of the sections and track along pilosebaceous units with deeper cuts. The epithelium matures normally to the surface. There is no inflammation or dysplasia.

Final diagnosis

A. Skin ("compund nevus"), right ala, shave biopsy - benign intradermal congenital-type nevus.

Compound nevus, congenital type - 2

The sections show a hair bearing skin with a melanocytic lesion involving both the deep epidermis and dermis. Melanocytes through-out the sections are small, lack nuclear atypia and nucleoli. Mitoses are not identified. In the, epidermis the melanocytes are basal and focally pigmented. In the superficial dermis the melanocytes are in nests and focally pigmented. In the deep dermis the melanocytes are smaller than in the superficial dermis, lack pigmentation and spindled. The lesion shows congenital features; melanocytes cluster around adenxal structures and blood vessels. The lesion is present at the margin.

Thick collagen bundles replace adenxal structures in the dermis focally and is associated with loss of rete ridges in the overlying epidermis; this is consistent with a prior excision at the site.

There is no evidence of malignancy and no significant inflammation.

Final

A. Cheek lesion ("nevus"), right, serial excision - Compound congenital-type nevus; lesional tissue extend to the multiple side margins but not the deep margins

Blue nevus

Microscopic description

The sections show a dermal lesion consisting of heavily pigmented epithelioid and spindle cells interspersed between collagen bundles. There is no nuclear atypia and the lesion does not extend into the superficial dermis. Lesional cells decrease in size and become more spindled with increasing depth. No mitotic activity is identified.

Final diagnosis

Skin, posterior thorax, biopsy: Blue nevus, see comment.

Comment: Nevus cells are seen focally at the edges of the section; clinical correlation for excision status is required.