Multinucleate cell angiohistiocytoma is a benign fibrohistiocytic and vascular proliferation that was first reported by Smith and Wilson Jones in 1985.  Multinucleate cell angiohistiocytoma occurs predominantly on the extremities of middle-aged and elderly women.
The pathogenesis of multinucleate cell angiohistiocytoma is unknown. Some authors consider it a connective-tissue disorder, while others categorize it as a vascular tumor. Wilson Jones concluded that multinucleate cell angiohistiocytoma is a chronic inflammatory disorder of unknown cause manifested by vascular hyperplasia and connective-tissue cells that have lost their function after prolonged stimulation. Cesinaro et al argue for a role played by estrogen in the development of this lesion. 
The frequency of multinucleate cell angiohistiocytoma in various races has not been reported.
The female-to-male ratio of persons affected with multinucleate cell angiohistiocytoma is approximately 5:1.
Reported cases of multinucleate cell angiohistiocytoma have occurred in patients aged 24-74 years. Most cases of multinucleate cell angiohistiocytoma occur in middle-aged and elderly women.
Multinucleate cell angiohistiocytoma is a benign condition. Spontaneous resolution is uncommon. No morbidity or mortality is associated with multinucleate cell angiohistiocytoma.