Multinucleated cell angiohistiocytoma: independent entity or variant of dermatofibroma? Rosettes and shiny white lines as new dermoscopic findings

Multinucleated cell angiohistiocytoma: independent entity or variant of dermatofibroma? Rosettes and shiny white lines as new dermoscopic findings Dear Editor, Multinucleated Cell Angiohistiocytoma (MCA) is an unusual benign vascular and fibro-histiocytic proliferation, predominantly affecting women aged 40 to 70 years. 1Clinically, it presents as asymptomatic violaceous or brownish papules, either solitary or clustered, primarily located on the dorsal hands and extremities, although generalized forms have also been described. 1,2These lesions may resemble annular granuloma, sarcoidosis, Kaposi sarcoma, lichen planus, or dermatofibroma. 1raditionally, MCA has been described as a vascular cutaneous tumor.Although its pathogenesis remains unclear, recent observations suggest it may instead represent a fibrohistiocytic process or a chronic inflammatory condition with fibrohistiocytic and vascular hyperplasia. 2,3Controversial hypotheses propose MCA as a particular variant of dermatofibroma, while others argue that it is a distinct entity with unique clinical, histological, and immunohistochemical characteristics. 2,4The influence of female hormones on its pathogenesis has also been suggested, supported by the identification of estrogen receptor alpha in interstitial and multinucleated cells, which may explain its higher prevalence in women. 5istologically, MCA is characterized by a proliferation of capillaries and venules in the superficial and mid-dermis, accompanied by prominent endothelial cells.Thickened collagen fibers parallel to the epidermis and frequent acanthosis of the epidermis are also observed.The most striking finding, although not pathognomonic, is the presence of multinucleated giant cells, typically positive for vimentin and factor XIIIa, with variable positivity for CD68.These