A leiomyoma, also known as a fibroid, is a benign smooth muscle tumor that very rarely becomes cancer (0.1%). They can occur in any organ, but the most common forms occur in the uterus, small bowel, and the esophagus. Polycythemia may occur due to increased erythropoietin production as part of a paraneoplastic syndrome. The word is from leio- + myo- + -oma, "smooth-muscle tumor". The plural form can be either the English leiomyomas or the classical leiomyomata. Uterus
Uterine fibroids are leiomyomata of the uterine smooth muscle. As other leiomyomata, they are benign, but may lead to excessive menstrual bleeding (menorrhagia), often cause anemia and may lead to infertility. A rare form of these tumors is uterine lipoleiomyoma—benign tumors consisting of a mixture of adipocytes and smooth muscle cells. Uterine lipoleiomyomata have been observed together with ovarian and other pathologies and some of them may develop into liposarcoma. These tumors are monoclonal, and non-random chromosomal abnormalities have been seen in 40% of the tumors. Gallbladder
Mesenchymal neoplasms of the gallbladder are rare and in particular leiomyomas of the gallbladder have been rarely reported, all of them in patients with immune system disorders. However, a case was reported in absence of associated immunodeficiency at Monash Hospital in Melbourne, Australia, in a healthy 39-year-old woman with no symptoms.
Tumor was intertwined with quadriceps muscles, making identification and excision difficult. Tumor was successfully excised with only minor rehabilitation required. Familial leiomyoma
Associated with papillary variant of renal cell carcinoma and multiple cutaneous leiomyoma. Defect is in the fumarate hydratase gene in the long arm of chromosome 1. See also
Leiomyosarcoma
Elagolix/estradiol/norethindrone acetate

References
External links

Esophageal Leiomyoma at eMedicine