[Isolated late-onset plexiform neurofibroma in the absence of neurofibromatosis].

BACKGROUND: Plexiform neurofibroma (NFP) is a benign nervous tumour typically involving the head and neck region due to the rich innervation of the latter. It is considered pathognomonic of neurofibromatosis type 1(NF1). This report describes an unusual case of neurofibroma and discusses its singular presentation, namely an isolated cutaneous tumour of late onset and with myofibroblastic histology. CASE REPORT: A 85-year-old man presented swelling of the cutaneous part of the lower palpebral region which had been present for several months. The lesion was relapsing after repeated incomplete excisions and had grown slowly to become firm and suspect. It was decided to perform a large excision with a frontal rotation flap. Initial histological examinations performed on each excision suggested fibrosis and scarring, leading to diagnosis of fibrocytic change and post-surgical neuroma. The final histological analysis indicated diffuse plexiform neurofibroma with a myofibroblastic component. This was a solitary lesion in a patient without any stigmata or familial history of NF1. DISCUSSION: This case is original in terms of its characteristics: a single cutaneous tumour of late onset in a patient with no stigmata of NF1 (in most cases of plexiform neurofibroma, NF1 is either multiple or else isolated at a mucous site). The histological findings for this tumour with a myofibroblastic component have never previously been described. Plexiform neurofibroma classically involves the head-and-neck region as in our case, with deep invasion of subcutaneous tissues making excision difficult and leading to frequent recurrence. 2010 Elsevier Masson SAS. All rights reserved.