REPORT OF A CASE
An 18-year-old woman presented to the Arizona Health Sciences Center Dermatology Clinic, Tucson, with a papule on her trunk that had been present as long as she could remember. The papule was asymptomatic; however, recent changes in color prompted her to seek medical attention. The patient had no other similar lesions on her body and no history of dermatologic disorders.Physical examination revealed a well-marginated, round, soft, unevenly pigmented, nontender papule, 1 cm in diameter, located on the trunk (Fig 1). The tumor had two adjacent pigmented macules, approximately 4 mm each, which were stable. Our clinical differential diagnosis included congenital nevocellular nevus, acquired compound nevus, nodular melanoma, nevus spilus, and blue nevus.An excisional biopsy was performed. Histologic findings are demonstrated in Figs 2 through 4.What is your diagnosis?
DIAGNOSIS:
Cellular blue nevus.
DISCUSSION
A cellular blue nevus is a rare benign dermal tumor characterized by its nondescript and variable clinical