Lipofibromatous hamartoma of the median nerve and its terminal branches: recurrent branch and ulnar proper palmar digital nerve of the thumb. A case report.

Lipofibromatous hamartoma (LFH) is a rare benign tumor affecting the peripheral nerves, particularly the median nerve. It is characterized by fatty tissue infiltrating the nerve. We report the case of a patient with LFH of the median nerve, recurrent branch and ulnar proper palmar digital nerve of the thumb associated with macrodactyly. It was responsible for hypoesthesia of the thumb's hemi-pulp and secondary carpal tunnel syndrome confirmed by electroneuromyography (ENMG). Diagnosis was suspected based on the MRI findings. The patient underwent surgical treatment consisting of open carpal tunnel release combined with neurolysis of the ulnar proper palmar digital nerve of the thumb. The extraneural LFH tissue was excised also. Forty-five days after surgery, the patient no longer had nocturnal paresthesia. Ninety days after surgery, sensitivity of the thumb pulp was satisfactory. Symptoms of LFH are related to the increased volume of the affected nerve. In the absence of symptoms, abstention seems to be the best option. In case of neurological clinical signs or ENMG abnormality, surgical treatment is indicated to perform neurolysis and excision of extraneural LFH tissue. The diagnosis is based on histological examination of tissue samples.