[Myxoid neurofibroma of the thumb]

Myxoid neurofibroma (MN) is a benign tumor of poorly identified perineural cell origin. We report a case of NM of left thumb and discuss the main differential diagnosis.

A 34-year-old woman presented with a painless, slowly progressive tumor of the left thumb of 6 months duration. This tumor had recurred after resection done 26 years before. Clinical examination revealed a tumor on the anterior surface of the left thumb, painless, firm, 4×3cm, ulcerated and covered with thin telangiectasia. The X-ray of the phalanx showed no alteration to the underlying bone. The histopathological study of a skin biopsy reported a myxoid neurofibroma. Excision of the lesion was performed with preservation of the nail. Neither the patient nor her family members had neurofibromatosis. The outcome was favorable and no recurrence was noted after 18 months of follow-up.

The usual sites of the MN are the face, shoulders, arms, and periungual regions. It is usually a solitary lesion; however, lesions may be multiple or recur after initial incomplete excision as in our patient. It must be considered in the differential diagnosis of tumors of the extremities. We report this case because of the rarity of both the tumor and its site.