A 16-year-old boy is brought to the office for examination, which reveals the lesion in...

The presence of multiple cutaneous lesions along with numerous longstanding subcutaneous tumors is most consistent with neurofibromatosis type 1 (NF1) . MCCQE objectives emphasize recognizing classic dermatologic findings of NF1, which include multiple neurofibromas (soft, skin-colored subcutaneous nodules) and characteristic pigmented lesions such as café-au-lait macules and axillary or inguinal freckling. These lesions typically develop during childhood or adolescence and increase in number over time.

Sarcoidosis can cause skin lesions but is not associated with multiple benign peripheral nerve sheath tumors. Dermatofibromas are usually solitary, firm nodules rather than numerous soft tumors. Vitiligo presents as depigmented macules without subcutaneous masses. Lipomatosis involves multiple lipomas but lacks the associated pigmentary skin findings seen in NF1.

NF1 is an autosomal dominant condition caused by mutation of the NF1 gene. Diagnosis is clinical based on established criteria. Recognition is important because patients require surveillance for complications such as optic gliomas, learning disabilities, skeletal abnormalities, and malignant peripheral nerve sheath tumors.