Lipofibromatous hamartoma is a rare benign neoplasm with a predilection for the median nerve. The tumor typically presents before adulthood and causes diffuse enlargement of the nerve with fibro-fatty tissues enveloping nerve fibers. The author reports his experience with ten cases of lipofibromatous hamartoma of the median nerve with attention directed toward associated pathologic findings in the involved hands. Five patients demonstrated macrodactyly of the thumb and index fingers, two patients had phalangeal exostoses, and two patients had localized hand lipomas. All of these conditions occurred in the radial aspect of the hand, corresponding to the anatomic distribution of the median nerve.
Other authors have documented an association between lipofibromatous hamartoma of the median nerve and macrodactyly, exostoses, lipomas, vascular tumors, and ectopic calcification of soft tissues (Yeoman, JBJS 46B: 737-739, 1964; Amadio, Rieman and Dobyns, JHS 13A: 67- 75, 1988). The author in this report hypothesizes that the tumor and its associated conditions may result from a genetic abnormality in end-organ responsiveness to an unidentified trophic factor. The true pathophysiology of lipofibromatous hamartomas and a consensus on treatment remain to be determined. Surgery is often limited to median nerve decompression and biopsy. Attempts at partial excision or interfascicular dissection can potentially lead to permanent loss of motor and/or sensory nerve function.