A parasitic leiomyoma is a considered a type of extra-uterine leiomyoma and presents as peritoneal pelvic benign smooth-muscle masses separate from the uterus.
It likely originates as a pedunculated subserosal leiomyoma that twists and torses from its uterine pedicle. The contact with the uterus is then lost.
Once free in the peritoneal cavity, it then survives by recruiting neo-vascularisation from adjacent structures. The originating pedunculated fibroid likely develops pre-menopausally, whereas the parasitic leiomyoma may become clinically evident either before or after menopause.
Occasionally a broad ligament leiomyoma is also classified under parasitic leiomyomas 4.
On imaging, a parasitic leiomyoma shows tissue characteristics similar to uterine leiomyoma.
Treatment and prognosis
With behaviour similar to uterine leiomyoma, a parasitic leiomyoma may recur after resection or, conversely, may show hormone-responsive behaviour, including size stability or even shrinkage with natural, surgical, or chemical menopause.
Surgery is usually performed for symptomatic relief or to prevent impingement of vital structures.
The differential for a parasitic leiomyoma varies with its location can include
- 1. Cohen DT, Oliva E, Hahn PF et-al. Uterine smooth-muscle tumors with unusual growth patterns: imaging with pathologic correlation. AJR Am J Roentgenol. 2007;188 (1): 246-55. doi:10.2214/AJR.05.1070 - Pubmed citation
- 2. Lurie S, Gorbacz S, Caspi B et-al. Parasitic leiomyoma: a case report. Clin Exp Obstet Gynecol. 1991;18 (1): 7-8. - Pubmed citation
- 3. Fasih N, Prasad shanbhogue AK, Macdonald DB et-al. Leiomyomas beyond the uterus: unusual locations, rare manifestations. Radiographics. 28 (7): 1931-48. doi:10.1148/rg.287085095 - Pubmed citation
- 4. Rader JS, Binette SP, Brandt TD et-al. Ileal hemorrhage caused by a parasitic uterine leiomyoma. Obstet Gynecol. 1990;76 (3 Pt 2): 531-4. - Pubmed citation