Table of Contents
Definition / general | Terminology | Epidemiology | Etiology | Clinical features | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosisCite this page: Desouki M. Leiomyoma-general. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/uterusleiomyoma.html. Accessed January 22nd, 2021.
Definition / general
- Extremely common tumor
- At autopsy, present in uterus in 77% of females; 84% of tumors are multicentric
Terminology
- Also called fibroid, myofibroma, fibromyoma, leiomyofibroma, fibroma, myoma
Epidemiology
- Present in 25% of women during reproductive years
- More common in blacks than whites; usually multiple in blacks
- Clinically apparent lesions are more common in nulliparous, postmenopausal women
Etiology
- May be due to xenoestrogens, a diverse set of environmental compounds which exist naturally (genistein) or are synthetic (diethylstilbestrol / DES) and bind to estrogen receptor (ER) in myometrium
- Somatic mutations and molecular alterations in X chromosome must occur for initiation and subsequent development of myomas
- Oral contraceptives and progestin-only injectables are associated with a reduced risk, particularly with prolonged use of oral contraceptives
- Meat consumption may be a risk factor and green vegetables a protective factor (Obstet Gynecol 1999;94:395)
Clinical features
- Typically asymptomatic, but up to 30% of women experience abnormal uterine bleeding or lower abdomen pressure related symptoms
- May interfere with pregnancy or block ureters if large
- Rarely associated with polycythemia, which regresses when the tumor is excised
- Estrogen responsive, may regress after menopause or castration, and enlarge during pregnancy
- Difficult to diagnose from D & C since resembles superficial myometrium
Case reports
- 32 year old woman with vaginal bleeding for two weeks and well circumscribed uterine mass with hemorrhage foci (Case of the Week #429)
- 49 year old woman with hysterectomy for fibroid uterus (Case of the Week #345)
Treatment
- If symptomatic, treat with myomectomy, leuprolide acetate depot, or GNRH analog that shrinks the tumor; asymptomatic tumors do not require treatment
Gross description
- Sharply circumscribed, round, firm, grayish white, "raw silk" and whorled cut surface
- Often shells out
- Bulging and trabeculated cut surface
- Usually within myometrium (intramural), may be submucosal or subserosal
- May be multiple
- Sampling: sample myxoid areas extensively to rule out myxoid leiomyosarcoma; sample all leiomyomas that lack the classic gross appearance of leiomyomas and 3 largest tumors
Gross images
Microscopic (histologic) description
- Whorled (fascicular) pattern of smooth muscle bundles separated by well vascularized connective tissue
- Smooth muscle cells are elongated with eosinophilic or occasional fibrillar cytoplasm and distinct cell membranes
- May develop areas of degeneration if large including hyaline or mucoid change, calcification, cystic change or fatty metamorphosis
- Usually noninfiltrative, thick walled arteries throughout and cleft-like spaces
- May have extensive hyaline necrosis if protrudes into endometrial cavity
- Variable lymphocytes and mast cells
- Usually less than 5 mitotic figures per 10 high power fields in most mitotically active area, no significant atypia
- Rarely has focal skeletal muscle differentiation (Hum Pathol 1999;30:356) or tubules / glands
- Post lupron treatment: initially edema and necrosis, then hyalinization and mild lymphocytic infiltrate
- Smooth muscle proliferations with unusual growth patterns: disseminated peritoneal leiomyomatosis; benign metastasizing leiomyoma; intravenous leiomyomatosis; lymphangioleiomyomatosis
Microscopic (histologic) images
Scroll to see all images.
Case #429
AFIP images
Contributed by Dr. Mowafak Hamodat
Case #345
Images hosted on other servers:
AFIP images
Contributed by Dr. Mowafak Hamodat
Case #345
Images hosted on other servers:
Positive stains
- Smooth muscle actin, muscle specific actin, desmin, h-caldesmon, vimentin
- Focal cytokeratin in 25% - 30%, especially epithelioid cases
- Occasionally focal CD10
Electron microscopy description
- Smooth muscle cells with varying degrees of differentiation
- In central regions, cells are characterized by filaments sporadically located in the cytoplasm and well developed organelles
- In outer layer, myocytes are more mature and resemble normal myometrial cells
Molecular / cytogenetics description
- 40% have nonrandom tumor specific chromosomal abnormalities; other 60% have normal chromosomal profiles
- Most common chromosomal rearrangements are t(12;14)(q14-q15;q23-q24), deletion (7)(q22q32), rearrangement of 6-6p21 (Cancer Genet Cytogenet 2005;158:1)
- Less common are karyotypic abnormal rearrangements of 1p36, 3q, 10q22, 13q21 - 22, trisomy 12 and X chromosome
- Increase in transforming growth factor beta in leiomyomata tissue
- Patients with germline mutations in fumarate hydratase have increased risk for developing leiomyomas, as well as uterine leiomyosarcomas
Differential diagnosis
- Endometrial stromal sarcoma with smooth muscle metaplasia
- Leiomyosarcoma