A case of uterus-like mass of the ovary associated with endometriosis.

•Coelomic metaplasia is considered to be one of the mechanisms resulting in endometriosis.•Intense ceolomic metaplasia resulted in a uterine like mass (ULM) acquiring the structural integrity of a miniature uterus.•ULM might be considered a rare manifestation in the spectrum of endometriosis development.