Rubin, Courtney B. BS^*; Boni, Andrea MD^†; Elenitsas, Rosalie MD^†; Pogoriler, Jennifer MD, PhD^‡; Low, David MD^§; Rubin, Adam I. MD^†

CLINICAL FINDINGS

A 9-year-old boy presented for evaluation of a pigmented lesion located on his lower back, over the spine. The lesion had been present since birth and had been growing proportionally with the patient. Physical examination revealed a blue plaque measuring 4 × 16 cm. Multiple small papules and nodules measuring 3–4 mm were noted within the larger plaque (Fig. 1). A magnetic resonance imaging of the back and spine showed no underlying abnormalities. A biopsy taken 7 years before from a nodular area showed histologic features consistent with cellular blue nevus. On request of the patient, a staged excision for complete removal was performed.

Figure 1

HISTOPATHOLOGICAL FINDINGS

The sections showed diffuse dermal infiltration by elongated dendritic melanocytes scattered throughout the dermis, which extended into the subcutis and fascia. Some areas had cellular nodules composed of spindle and epithelioid cells reminiscent of a cellular blue nevus. Perivascular, perineural, and periadnexal extension of lesional melanocytes were present. The epidermis was unaffected. The histologically noted cellular nodules correlated clinically to the papules and nodules seen in the larger background plaque. There were no lesional mitoses, necrosis, or cytologic atypia (Fig. 2).

Figure 2

WHAT IS YOUR DIAGNOSIS?

(Continued on page e58)