Diffuse neurofibroma

Introduction

Diffuse Neurofibroma is a newly recognised distinct clinical entity. It is an unusual variant of neurofibroma. Dahl et al have first reported four cases of diffuse neurofibroma in young adults. All of them presented with hard sclerotic plaques with irregular surfce but with out protruding nodules.[1] The plaques varied from 3 cms to 8 cms in size.[2] Head and neck are the common sites of involvement.[2],[3],[4] Diffuse neurofibroma although benign in nature spreads superficially and has many ectatic blood vessels.[5] Histologically, the tumour consists of spindle cells with fibrillar cytoplasm and elongated nuclei.

Case Report

A 30-year-old man presented with nodular swelling on the frontal region of scalp of 3 years duration. He was asymptomatic 3 years back, then he developed single nodule on sclerotic plaque involving frontal region. Gradually multiple nodules developed over a period of 1 year. Cutaneous examination revealed skin-coloured nodules in the frontal region of scalp. Nodules varied from 2 to 4 cms in size, firm in consistency, not mobile, not tender. Skin over the swelling was not pinchable. Mucous membrane and genitalia were normal. Systemic examination was also normal. He was provisionally diagnosed as a case of pilomatrixoma. However, Eccrine hidroadenoma, dermal cylindroma, eccrine spiroadenoma were also considered in the differential diagnosis. Routine laboratory investigations were within normal limits. X-ray skull did not show any bony involvement. Histopathology of skin biopsy revealed spindle cells with fibrillar cytoplasm and elongated nuclei, which confirmed the diagnosis of diffuse neurofibroma.

Discussion

The reported case presented with hard sclerotic plaque with nodules on the frontal region. He was provisionally diagnosed as a case of pilomatrixoma. The differential diagnosis considered were eccrine hidroadenoma, dermal cylindroma and eccrine spiroadenoma. The diagnosis of diffuse neurofibroma was not entertained as the patient did not have cafe-au-lai macules and molluscum fibrosum. However biopsy form sclerotic plaque showed typical features of diffuse neurofibroma. Hence it is pertinent to include diffuse neurofibroma as one of the differential diagnosis when the patient presents with hard sclerotic plaque. Our patient of diffuse neurofibroma is a young adult which is similar to the case report by Dahl et al where all his patients were young adults.[1] All the four cases reported by Dahl et al presented with sclerotic plaques without protruding nodules. Scalp is the site of involvement in the reported case which is similar to the case report by chowdary et al.[3] Review of Indian literature failed to reveal any case report of diffuse neurofibroma. The case is reported for its rarity and its unique presentation.