A 42-year-old woman, gravida 4 para 4, comes to the office due to heavy and painful menstrual bleeding over the past 3 months. The patient's last menstrual period was 3 weeks ago. Menarche was at age 10, and menstrual periods last for 3-5 days and occur every 30 days. She is sexually active with her husband and does not have pain with intercourse. The patient had a bilateral tubal ligation 3 years ago after the birth of her last child. She takes no medications and has no allergies. BMI is 24 kg/m2. Vital signs are normal. On bimanual examination, the uterus is uniformly enlarged and tender. Urine β-hCG is negative. Which of the following is the most likely cause of this patient's symptoms?
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This patient has adenomyosis, a disorder caused by an abnormal collection of endometrial glands and stroma within the uterine myometrium. Adenomyosis is common in multiparous women, and prior uterine surgery (eg, cesarean delivery) is a risk factor.
Although the exact pathogenesis is unclear, adenomyosis may occur due to endometrial invagination into the myometrium during periods of myometrial weakening or changes in vascularity at the endomyometrial interface (eg, pregnancy, uterine surgery). The clinical features of adenomyosis reflect its pathophysiology:
Definitive therapy is with hysterectomy, which allows for histologic diagnosis.
(Choice A) Leiomyomas (ie, uterine fibroids) are benign myometrial smooth muscle cell tumors. Although fibroids can cause regular, heavy menses (also due to increased endometrial surface area), the uterus is typically nontender and irregularly enlarged rather than tender and uniformly enlarged.
(Choice B) An ectopic pregnancy most commonly occurs due to abnormal blastocyst implantation in the fallopian tube. Although prior tubal surgery (eg, bilateral tubal ligation) is a risk factor, ectopic pregnancy is unlikely in this patient with a negative urine β-hCG. In addition, uterine enlargement would not be seen.
(Choice D) Endometrial polyps are benign, intracavitary, focal hyperplastic growths of endometrial tissue. In contrast to adenomyosis, endometrial polyps cause painless intermenstrual bleeding rather than painful, cyclic, heavy menses. There is also no associated uterine tenderness or enlargement.
(Choice E) Patients with endometrial hyperplasia have unregulated endometrial gland proliferation with increased gland-to-stroma ratio; the thickened endometrial lining may slightly increase uterine size and cause heavy menses. However, endometrial hyperplasia does not typically cause dysmenorrhea or uterine tenderness. In addition, the most common risk factor is unopposed estrogen from chronic anovulation and/or obesity; this patient has regular menses and a normal BMI.
Educational objective:
Adenomyosis is the abnormal presence of endometrial glands and stroma within the uterine myometrium. Affected patients are typically multiparous women with dysmenorrhea, heavy menses, and a uniformly enlarged uterus.