Mesometrial smooth muscle as an origin of female retroperitoneal (pelvic) leiomyomas

Abstract

Retroperitoneal (pelvic) leiomyomas have recently come to be recognized as distinctive lesions. Retroperitoneal leiomyomas occur almost exclusively in women, and past studies on these invariably emphasized a striking similarity between their histological features, with those of uterine leiomyoma, whereas their origin remains unknown. In this study, we took notice of mesometrial smooth muscle, which has been little known either clinically or pathologically, as a possible origin of tumor. Anatomically, the mesometrial smooth muscle was an accumulation of thin bundles (approximately 1 mm in thickness) that ran parallel to the oviduct. It was connected broadly with the lateral wall of the uterine body and ended in the pelvic floor. The mesometrial smooth muscle was present just beneath the serosal surface of the anterior aspect of the mesometrium and continuously transited from the smooth muscle bundles of the outer layer of the uterine myometrium. The muscle cells were immunopositive for smooth muscle cell markers and estrogen/progesterone receptors. In all of the six female retroperitoneal leiomyomas examined, hormone receptor-positive nontumorous smooth muscle layers were present in the periphery of the tumors, seemingly representing the mesometrial smooth muscles. In conclusion, we believe most retroperitoneal (pelvic) leiomyomas in females arise from the mesometrial smooth muscle.

Giant abdominopelvic retroperitoneal leiomyoma

“…Pelvic leiomyomas are thought to be separate primary lesions of mesometral tissue origin of about 1 cm bundles located parallel to the Fallopian tube with expansion toward the free pelvic space. Constructed of smooth muscle cells may have estrogen/progesteron receptors (ER/PR) [3]. Chronic pelvic pain, dysmenorrhea, abdominal enlargement, problems with urination (urinary retention, hy- droureteronephrosis) or defecation and constipation are the most common signs of pelvic tumor formation that is most commonly associated with myomatous uterus or adnexal pelvic mass [2].…”

Leiomyoma in the Retzius space

“…Other authors think that extraperitoneal leiomyomas originate from the remains of the Müllerian or Wolffian ducts or from the smooth muscles cells of the vascular walls [ 7 , 14 ]. In 40% of cases retroperitoneal leiomyomas co-exist with uterine leiomyomas or can be related to past hysterectomy [ 3 , 15 ].…”

A Rare Case of Retroperitoneal Leiomyoma

“…The most common sites of fibroid are uterus and GIT; however, it can originate wherever smooth muscle cells exist [4, 6, 7]. The extrauterine leiomyoma presentations mentioned in the literature are benign metastasizing leiomyoma, disseminated peritoneal leiomyomatosis, intravenous leiomyomatosis, parasitic leiomyomata, and retroperitoneal growth, and the unusual sites of origin include the vulva, ovaries, urinary bladder, and urethra.…”