Discussion of Lipofibromatous hamartoma
- Proliferation of mature adipocytes within peripheral nerves resulting in a palpable yellow neurogenic mass.
- Mature fat infiltrates the nerve, separating axonal bundles sheathed in perineurium, which normally lie adjacent to each other.
- Lipofibromatous hamartomas are rare.
- Patients typically present in their third or fourth decade of life with a long history of painless swelling in the distal forearm that often was first noted in childhood.
- The median nerve is the most commonly involved peripheral nerve, with involvement of other peripheral nerves of the upper extremity reported less frequently.
- Patients with median nerve involvement commonly present with carpal tunnel syndrome.
- Before the widespread availability of MRI, the diagnosis of lipofibromatous hamartoma was confirmed after exploratory surgery and biopsy of the lesion.
 Imaging Findings for Lipofibromatous hamartoma
- The pathognomonic pattern is an enlarged nerve containing 15 or 16 coaxial "cables" or bundles of axons encased in epineural fibrous tissue.
- In the region of the carpal tunnel, the neural bundles were evenly interspersed with fat, such that the cross-sectional area of the median nerve is increased to 0.6-1.6 cm2.
- Sonography showed the characteristic hypoechoic coaxial cabling encased by an echogenic substratum.
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 References for Lipofibromatous hamartoma
- Toms, Andoni P., Anastakis, Dimitri, Bleakney, Robert R., Marshall, Thomas J. Lipofibromatous Hamartoma of the Upper Extremity: A Review of the Radiologic Findings for 15 Patients. Am. J. Roentgenol. 2006 186: 805-811