The correct answer is C: Leiomyoma
A 48-year-old African American female presents with severe uterine bleeding. Pelvic examination revealed an enlarged irregularly shaped uterus. A large mass was noted by ultrasonography and the uterus was removed. A section of the mass is evaluated.
Comment: Leiomyomas (fibroids) are very common benign uterine tumors. It is estimated that 25% of women in their reproductive years will develop fibroids. They rarely progress into a malignancy. Until recently, it was thought that both progesterone(Drug information on progesterone) and estrogen were the prime influencing factors in fibroid formation and there is considerable evidence that supports their involvement. Recent studies, however, indicate that other factors may also play key roles. These include an inherited component and also growth factors such as: transforming growth factor-beta, fibroblast growth factor, epidermal growth factor and platelet-derived growth factor.
The exact inherited component is unknown at this time but the fact that fibroids run in families is an indicator that one or more will be found. Further, a recent study demonstrated that 70% of fibroids exhibited mutations in MED12. These studies, and others, provide the current working hypothesis on fibroid development. There are most likely several factors involved: 1) A genetic predisposition, 2) hormones (including those of environmental origin), and 3) growth factors. Risk factors also include: obesity, diabetes, nulliparity, hypertension, and being of African American descent. Click here for the comparative pathology.
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References:
Hassan MH, Eyzaguirre E, Arafa HM, et al. Memy I: a novel murine model for uterine leiomyoma using adenovirus-enhanced human fibroid explants in severe combined immune deficiency mice. Am J Obstet Gynecol. 2008;199:156.e1-8.
PMID: 18468574
Mäkinen N, Mehine M, Tolvanen J, et al. MED12, the mediator complex subunit 12 gene, is mutated at high frequency in uterine leiomyomas. Science. 2011;334:252-255. PMID: 21868628
Maruo T, Ohara N, Wang J, Matsuo H. Sex steroidal regulation of uterine leiomyoma growth and apoptosis. Hum Reprod Update. 2004;10:207-220.
PMID: 15140868
Rein MS. Advances in uterine leiomyoma research: the progesterone hypothesis. Environ Health Perspect. 2000;108 Suppl 5:791-793. PMID: 11035984
Romagnolo B, Molina T, Leroy G, et al. Estradiol(Drug information on estradiol)-dependent uterine leiomyomas in transgenic mice. J Clin Invest. 1996;98:777-784. PMID: 8698870
Tanwar PS, Lee HJ, Zhang L, et al. Constitutive activation of Beta-catenin in uterine stroma and smooth muscle leads to the development of mesenchymal tumors in mice. Biol Reprod. 2009;81:545-552. PMID: 19403928
Tsuiji K, Takeda T, Li B, et al. Establishment of a novel xenograft model for human uterine leiomyoma in immunodeficient mice. Tohoku J Exp Med. 2010;222:55-61. PMID: 20814179
