Lipoma of the uterus: clinical and ethiopathological approach of 7 cases with immunohistochemical study of histogenesis

Lipoleiomyoma of the uterus (LLU) is an extremely rare, benign, uterine tumour. This rare disease was unknown for a long time. Their histogenesis remains controversial. To describe the clinical and pathological aspects of uterine lipoleiomyoma and to try to specify, by an immunohistochemical study, its degenerative or tumoral nature. 7 cases of LLU were identified represented by 2 pure Lipoma and 5 Lipoleiomyoma. We performed an immunohistochemical study including anti-vimentin, anti-smooth muscle actin, anti PS-100, anti-desmin, anti-factor VIII and anti-HMB- 45. The results were correlated with the pathogenesis of this lesion. Immunohistochemical analysis showed an expression of PS 100 only in lipocytes whereas leiomyomatous cells express only smooth muscle actin. Our study supports the benign tumoral nature of the fatty uterine lesions. Lipoleiomyomatous cells may originate from the transformation of a totipotent mesenchymal cell and not from a degenerative process.