Lipomatosis of nerve (LN) is a massive enlargement of a nerve due to abundant proliferation of adipose and fibrotic tissue within the epineurium-part of the spectrum of adipose lesions of nerves, including intra- and extraneural lipomas. LN has been frequently associated with soft-tissue and/or osseous overgrowth. Unfortunately, much confusion exists since many names have been used for LN (e.g., fibrolipomatous hamartoma, macrodystrophia lipomatosa, and so on). To better understand this condition and to evaluate its association with nerve-territory overgrowth, the authors attempted to compile the world\'s literature on published LN cases.
PubMed and Google Scholar databases were searched to identify published articles on LN cases, using a variety of terms. Publications in all languages were assessed. All publications with cases determined likely to be LN were read. Cases that provided clear clinicopathological and/or radiological evidence of LN were labeled as \"definite\" and cases that demonstrated features of LN (e.g., nerve-territory overgrowth) but lacked definite proof of nerve involvement were labeled as \"probable.\"
Initial screening revealed a total of 2465 papers. After exclusions, 281 publications reported cases with a definite diagnosis of LN and 120 articles reported cases with a probable diagnosis of LN. The authors identified 618 definite and 407 probable cases of LN. Sex distribution was balanced (51% female). Early diagnosis was common, with two-thirds of patients having symptoms in the 1st decade of life. The most commonly affected nerve was the median nerve (n = 391). Nerve-territory overgrowth was common (62% definite LN; 78% combined cases); overgrowth was exclusive to the territory of the affected nerve in all cases but 5.
The authors present a comprehensive review and analysis of the literature of LN cases. One of the main findings was the nerve-territory overgrowth was associated with LN, especially when present earlier in life. The authors believe that all cases of LN associated with overgrowth can be explained on anatomical grounds, even in the few reported cases in which this is not immediately obvious.

Neural fibrolipomas are exceedingly rare benign tumors composed of hypertrophied fibrofatty tissue intermixed with nerve tissues. Our review of the published data identified only 15 cases of this tumor involving the foot and/or ankle region. An otherwise healthy 35-year-old male was referred for evaluation of a painless soft tissue mass present in the anterior left ankle. The mass had been present for approximately 6 to 7 years and had recently increased in size. Physical examination demonstrated a prominent, fluctuant mass present in the left ankle measuring 4 cm in diameter. The mass was not well-defined, was immobile, and did not transilluminate. No gross pedal deformity was present. Radiographic imaging revealed increased soft tissue prominence and density to the anterior ankle without bone involvement. Magnetic resonance imaging demonstrated a mass isointense to fat on all sequences without contrast enhancement, suggestive of a lipoma. Surgical excision was performed; the mass was yellow and lipomatous in nature. The mass was intimately associated with the superficial peroneal nerve, which had to be sacrificed during excision. The pathologic examination of the mass revealed findings consistent with a neural fibrolipoma. The patient healed uneventfully without recurrence. His only complaint was of some residual numbness in the medial foot.