Fibrolipomatous gigantism, hemihyperplasia multiple lipomatosis syndrome


Phenotypes from the spectrum of PIKCA-related circumscribed overgrowth syndromes (PROS) with a predominant soft tissue component in the form of lipomatous/fibroadipose overgrowth and frequent skeletal involvement. The vascular changes are quite subordinate and, if present, mostly occur as capillary malformations (CM). If large vessels are involved in the form of vascular malformations, the clinical picture is assigned to CLOVES syndrome. A minimal variant of fibrolipomatous gigantism is macrodactyly fibrolipomatosis.

Clinical presentation

Asymmetry from birth due to circumscribed overgrowth in the extremities (mostly feet) in fibrolipomatous gigantism or overgrowth of one half of the body in hemihyperplasia multiple lipomatosis syndrome (HHML). Subcutaneous, visceral, muscle-infiltrating regional lipomatosis (circumscribed fat hyperplasia), rarely lipomas. During adolescence a major growth phase, often progression of fibrolipomatous overgrowth. In HHML, growth tends to be proportional and not exuberant, whereas in fibrolipomatous overgrowth the clinical picture is characterized by circumscribed, disproportionately progressive gigantism.


  • Multidisciplinary and symptomatic
  • Primarily conservative
  • Careful with surgical overgrowth tissue reductions and orthopedic measures
  • Possibility of excessive dysregulated tissue hyperplasia after surgical resection is described
  • In the case of massive progressive hyperplasia, consider mTOR inhibition