Pilomatrixoma of the Neck/Shoulder Region Mimicking a Rapidly Growing Neoplasm of Peripheral Nerve Sheath Origin in Neurofibromatosis Type 1.

Neurofibromatosis type 1 (NF1) is an autosomal dominant hereditary disorder. Neurofibroma is the most common neoplasm of this disease. This lesion is characterized by circumscribed soft or knotty skin tumors derived from peripheral nerve sheath cells. Numerous other neoplasms have been described for this tumor predisposition syndrome. This case report adds the diagnostic and therapeutic procedures in the case of an NF1 patient in whom the rapidly growing, nodular, subcutaneous tumor initially led to the suspicion of a malignant neoplasm. The tumor proved to be pilomatrixoma, which closely adhered to a neurofibroma.