Neurolipoma of the digit

Soft tissue masses of the fingers have a broad differential, including both benign and malignant etiologies. Of these, lipomatous tumours of the finger are exceedingly rare, with the subset of neurolipomas, rarer still. Often referred to as lipofibromatous hamartoma (LFH), or lipomatosis of nerve, among more than ten other descriptive terms, these tumours are generally associated with macrodactyly and frequently involve branches of the median nerve of the upper extremity, leading to a spectrum of neurologic sequelae. These tumours represent a diagnostic challenge due to their rarity and neural involvement, which may complicate standard biopsy techniques. Optimal surgical management is dependent on the final diagnosis, if known, or clinical judgement when a biopsy is not feasible. We present a case of a 17-year-old male with an index finger lipomatous soft tissue mass with lesional enhancement seen on imaging. The decision was made to perform an excisional biopsy, with intralesional dissection and preservation of the involved digital nerve. Based on the pathologic findings, he was diagnosed with neurolipoma of the finger without associated macrodactyly. Given the benign nature of these lesions, marginal excision without sacrifice of the involved nerve is recommended. Still, a high index of suspicion should always be employed if an underlying malignancy is suspected in which case wide excision, or amputation would be the treatment of choice after the diagnosis is confirmed. The diagnostic, intraoperative, and postoperative findings of the case are discussed.