gms | German Medical Science

Objectives/Interrogation: Lipofibromatous hamartoma is a rare benign tumour which is characterised by diffuse infiltration of peripheral nerves by fibrous and adipose tissues.

In 2013, a comprehensive literature review by Tahiri et al. reported that there have been 180 known cases of lipofibromatous hamartoma of the median nerve published in literature; to the best of our knowledge there have been approximately 10 more cases published since that time.

We are reporting a case of lipofibromatous hamartoma of the median nerve in the hand and its digital branches.

Case Report: A 39-year-old lady presented with gradually decreasing sensations along the ulnar border of her thumb for six months. She reported having a swelling affecting her thumb since birth. Examination revealed soft nontender lump on the first web space and ulnar side of the thumb with some numbness and no motor deficit.

MRI scan showed thinly capsulated non-enhancing lobulated predominantly fatty lesion centred around the median nerve and its digital branches in the hand and wrist. The fat was noted to insinuate between the nerve fibers. The appearances were in keeping with lipofibromatous hamartoma.

Median nerve was explored, and its branches were identified. The ulnar digital nerve of thumb was totally taken over by disease and therefore excised. The radial digital nerve of the index was involved at flexor zone 2; the lesion was dissected without nerve interruption.

Microscopic examination showed multiple nerve bundles and Pacinian corpuscles surrounded large amounts of mature fibrofatty tissue. The nerve fascicles themselves were preserved and showed only perineural fibrosis. These features confirmed the diagnosis of lipofibromatous hamartoma.

Results and Conclusions: Lipofibromatous hamartoma is a rare and benign fibro-fatty tumour of unknown etiology. To date, there have been less than 200 cases reported in literature. Approximately one third of the cases had associated macrodactyly.

MRI scan is pathognomonic modality for Lipofibromatous hamartoma diagnosis. Treatment options range from observation of asymptomatic cases to prophylactic carpal tunnel release with or without neurolysis in symptomatic patients. A biopsy is recommended with carpal tunnel release to confirm diagnosis. Treatment of macrodactyly, if present, should be addressed separately.