[A case of leiomyomatosis in pelvic lymph nodes].

We report a rare case of leiomyomatosis in iliac lymph nodes, which was found in a woman operated with a diagnosis as keratinizing epidermoid carcinoma of the cervix. A 39-year-old Japanese female, married, who had received hormonal therapy in her past history, visited the Department of Obstetrics and Gynecology at Kinki University Hospital, with a chief complaint of bloody discharge. Colposcopy and biopsy suggested a diagnosis of keratinizing epidermoid carcinoma of the cervix. A radical hysterectomy and bilateral salpingo-oophorectomy with pelvic lymph nodes dissection was performed. Histopathological examination showed a keratinizing epidermoid carcinoma of the cervix. An intramural leiomyoma nodule (0.5cm in diameter) was detected in the fundus of the uterus. Histopathologically, this was a typical benign leiomyoma. The lymph nodes were free of neoplasms. But bilateral iliac lymph nodes were enlarged up to soybean size. Microscopically, the iliac lymph nodes contained a large amount of well differentiated smooth muscle tissue (11/30). Immunohistochemical investigation showed a positive reaction for smooth muscle actin and desmins in the spindle cells proliferated in the lymph nodes; no cytokeratin positivity was detected. Leiomyomatosis of lymph node may rise through metaplasia of intranodal decidua or endometriosis by myofibroblasts or smooth muscle cells, reflecting the multipotentiality of the pelvic subcoelomic mesenchyme that can be found in the peripheral sinus of lymph nodes.