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Pink papule on thigh

A 57-year-old woman presented to Dermatology for a rosacea follow-up appointment. During the visit, she mentioned a painful lesion on her thigh that had been present for at least a month. An exam revealed a 4- to 5-mm pink ulcerated papule. Dermoscopy did not reveal any pigmentary features of a melanocytic lesion (network, streaks, globules, or homogeneous blue color) but there was 1 markedly atypical serpentine vessel.1

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A deep-shave biopsy indicated that this was an inflamed/irritated solitary neurofibroma. Basal cell carcinoma, inflamed nevus, and Merkel cell carcinoma were also considered.

Most often manifesting in adults, solitary neurofibromas are common nonencapsulated, soft to firm papules that range in size from 2 mm to 2 cm. Solitary neurofibromas are benign and work-up for systemic neurofibromatosis is not indicated. However, if a patient presents with multiple neurofibromas, axillary freckling, or multiple café au lait macules, systemic disease should be considered, followed by molecular testing and/or referral to a medical geneticist or neurofibromatosis clinic.

Although both the triage amalgamated diagnostic algorithm and the 2-step dermoscopy algorithm suggested this lesion was higher risk, it was ultimately found to be benign. This case highlights areas in which dermoscopy and physical exam lack specificity, but this trade-off increases the sensitivity of an algorithmic approach. Solitary pink papules can include some subtle, but fearsome, diagnoses and deserve close attention. In this case, the biopsy not only helped confirm the diagnosis, but it also alleviated the discomfort caused by the neurofibroma.

Text courtesy of Jonathan Karnes, MD, medical director, MDFMR Dermatology Services, Augusta, ME. Photos courtesy of Jonathan Karnes, MD (copyright retained).

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