Abstract

Dermal hyperneury is an uncommon small nerve hypertrophy defined as the presence of larger nerve fibers in the dermis. It may be localized or multiple and appear sporadically or associated with syndromes including Cowden syndrome, neurofibromatosis type II and multiple endocrine neoplasia 2B and 2A. The sporadic form may be related to neoplastic or non-neoplastic dermal lesions including nodular prurigo. In the systemic form, the risk of malignancy is higher in the thyroid, bread or endometrium. We report a case of a 50-year-old male with a scalp lesion that was sore and present for 2 years. He had a history of eczema, prediabetes, hypertension, dyslipidemia, gout and hypothyroidism. There was a 7-8 mm subtle erythematous ill-defined nodule on the right scalp. A punch biopsy was performed which revealed thickened nerve fibers in the superficial and deep dermis and around adnexa and sebaceous glands. There was a mild, non-specific lymphohistiocytic proliferation in the superficial dermis and around the adnexa. Deeper levels did not reveal a specific inflammatory or neoplastic process. The nerves remained distinct, without tumor formation. A Fite stain was negative for organisms and levels did not reveal the perineural extension of tumor cells. There is a morphologic similarity between hyperneury and mucocutaneous neuromas. Mucocutaneous neuromas may appear in Cowden syndrome as larger circumscribed tumors of neural tissue whereas hyperneury is hyperplastic nerve. Epithelial sheath neuroma may show similar-appearing nerves, but these are associated with benign perineural squamous epithelium.

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