Contributed by Muammar Arida, MD and Drazen M. Jukic, MD, PhD
Published on line in June 2003
An otherwise healthy male in his 20s presented with a 0.95 cm shiny unequally pigmented erythematous papule in the left supraclavicular area to a private dermatology clinic. The clinical suspicion was that of pigmented basal cell carcinoma. The lesion was completely excised and submitted for histopathologic examination (see specimen #1). The lesion has been sent to our dermatopathology practice for a consultation. Several months later, in our hospital, the patient underwent excision of two clinically "atypical nevi" (specimen #2: midline lower back; specimen #3: left lower back). After about 2 months yet another pigmented lesion clinically suspicious for malignancy was excised from this patient's lower back (specimen #4)
Specimen #1 "Left supraclavicular":
Low power view reveals a well-circumscribed dome-shaped hypercellular dermal neoplasm with a prominent deep component that shows scattered pigmentation (Fig. 1-1). Closer inspection reveals two distinct cellular populations: First, smaller basophilic melanocytes with regular outlines and scant cytoplasm, and second, a confluent proliferation of moderately pleomorphic melanocytes with abundant amphophilic cytoplasm , round to oval nuclei, dispersed chromatin and prominent nucleoli. Several mitotic figures are observed in the deeper portion of this component (Figs. 1-2 and 1-3). Focal small nests composed of melanocytes of similar appearance are seen at the dermo-epidermal junction (Figs. 1-2 and 1-5). The distinct deep component also features nests of spindle and epithelioid melanocytes and scattered melanophages (Fig. 1-4).
The following Immuostains were performed:
Specimen #2 "Midline lower back":
This is a 0.3 cm densely cellular, mainly dermal neoplasm with overlying hyperplastic epidermis (Fig. 2-1). It is composed of large epithelioid melanocytes with abundant cytoplasm and "histiocytoid" and "rhabdoid" features (Fig. 2-2). A focal, but distinct junctional component is observed (Fig. 2-3). The deep portion of this neoplasm shows some features of probable congenital onset, such as smaller melanocytes that show maturation with progressive descent and splaying between the collagen bundles (Fig. 2-4). Three mitotic figures were seen in the dermal component (Fig. 2-5). Ki-67 immunostain stains about 5% of the melanocytes (Fig. 2-6).
Specimen #3 "Left lower back":
See figures 3-1 3-2 3-3 3-4
Specimen #4 "Lower back":
See figures 4-1, 4-2.