Cotyledonoid dissecting leiomyoma with intravascular growth pattern and intra-tumoural endometrial glands and stroma: A case report

Cotyledonoid dissecting leiomyoma (CDL) is a rare variant of leiomyoma which shows a dissecting growth pattern of smooth muscle cells within the myometrium, with or without extra-uterine extension, and a macroscopic appearance resembling placenta. We present a unique case of CDL with both intravascular growth and presence of endometrial glands and stroma within the tumour. A 35-year-old female patient presented with menorrhagia. Ultrasound examination revealed a bulky anteverted uterus with a prolapsed submucosal leiomyoma and an intramural leiomyoma. In the interest of preserving fertility, she underwent myomectomy together with laparoscopic resections of the uterine wall deposit and myometrial tissue. The tumour was soft and pink, with a resemblance to placental tissue, and histology demonstrated nodules of neoplastic smooth muscle cells with areas of oedema and myxoid change dissecting into the surrounding myometrial tissue, which is consistent with the features of CDL. Also seen were non-neoplastic endometrial glands cuffed by stroma located within the smooth muscle tumour as well as in the non-neoplastic myometrium. There were foci of intravascular luminal growth confirmed by positive CD31 immunohistochemical staining of the endothelial cells lining the vascular lumina. The present case demonstrates that CDLs may have a unique histological appearance resembling adenomyoma and an intravascular growth pattern. It is important for pathologists, gynaecologists and radiologists to recognize such smooth muscle tumour variants and hence prevent misdiagnosis of malignancy and overtreatment.