- Macrodactyly, usually of the 2nd and 3rd digits, that is associated with fibrolipomatous hamartoma of the plantar nerve (lower extremity) or median nerve (upper extremity)
- Characteristic MRI findings: soft tissue and osseous overgrowth of digit with increased surrounding fat deposition, lateral bowing and osteoarthritic changes of affected digits, thickening of plantar nerve (lower extremity) or median nerve (upper extremity)
- Surgical management chosen to correct cosmetic abnormalities and minimize functional impairment
- Macrodystrophia lipomatosa is a rare congenital form of localized gigantism of the digits that is characterized by overgrowth of all mesenchymal elements, particularly fibroadipose tissue.
- Although the pathogenesis of this disorder remains unknown, lipomatous degeneration, alterations in fetal circulation, trophic influences of tumified nerve, and local suppression of growth limiting factors, have been suggested as possible etiologies.
- Clinical manifestations usually present in early childhood as macrodactyly in a median or plantar nerve distribution with progressive enlargement of the involved digits occurring until puberty.
- The phalanges are long and broad, and lateral bowing resulting from excessive tissue overgrowth along the volar and distal aspects of the affected digits may result in pain due to premature secondary osteoarthritis.
- Other disorders which can produce overgrowth of the digits include neurofibromatosis-1, Klippel-Trenaunay-Weber syndrome, hemangiomatosis, Ollier's disease, and Maffucci's syndrome. However, MR imaging using fat sensitive sequences which demonstrate fibrolipomatous thickening of the median or plantar nerve and enlarged digits surrounded predominantly by normal fatty tissue usually secures the diagnosis.
- Though controversial, surgical management is advocated to correct the cosmetic deformities and minimize functional limitations in affected patients, especially in adolescents and young adults.
Reference: Murphey MD, Smith WS, Smith SE, et al. Imaging of musculoskeletal neurogenic tumors: radiologic-pathologic correlation. Radiographics. 1999;19:1253-1280.
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