A 15-year-old girl comes to the office due to pelvic and crampy lower abdominal pain that seems to recur at the beginning of each month and resolves after a day or two. The pain began approximately 6 months ago and has significantly worsened each month. The patient has never had a menstrual period. She has never had sexual intercourse. Weight, height, and BMI are average for age and sex. Breast and pubic hair development are at sexual maturity rating (Tanner stage) 5. Digital rectal examination reveals a palpable mass anterior to the rectum. A pregnancy test is negative. Which of the following is the most likely diagnosis?

Question

A 15-year-old girl comes to the office due to pelvic and crampy lower abdominal pain that seems to recur at the beginning of each month and resolves after a day or two.  The pain began approximately 6 months ago and has significantly worsened each month.  The patient has never had a menstrual period.  She has never had sexual intercourse.  Weight, height, and BMI are average for age and sex.  Breast and pubic hair development are at sexual maturity rating (Tanner stage) 5.  Digital rectal examination reveals a palpable mass anterior to the rectum.  A pregnancy test is negative.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec160b_3572_a661_9249_b1d9d201d756_MD0001_00 This 15-year-old girl has never menstruated (ie, primary amenorrhea), which can result from functional (eg, hypothalamic amenorrhea) or anatomic abnormalities. In adolescents with normal secondary sexual characteristics (which suggest intact hormonal function) and cyclic abdominopelvic pain (which suggests menstruation), the most likely cause is genital tract outflow obstruction (eg, imperforate hymen). An imperforate hymen occurs due to incomplete degeneration of the hymen prior to birth. At menarche, blood accumulates behind the hymen, and the expanding collection with each menstrual period causes increasing pressure on the pelvic organs (eg, defecatory/urinary dysfunction) and worsening abdominopelvic pain with no apparent menstrual bleeding. As a result of pooled blood behind the hymen, physical examination typically reveals a smooth vaginal bulge (hematocolpos) and a palpable mass anterior to the rectum (ie, the distended vagina). Treatment is with hymenal incision and drainage, which resolves the obstruction and amenorrhea. (Choice A) Androgen insensitivity syndrome causes primary amenorrhea due to the lack of müllerian structures. Patients are 46,XY males but appear phenotypically female (ie, no external male genitalia) due to an androgen receptor defect. These patients have normal breast development due to peripheral aromatization of testosterone to estrogen and may have palpable prostate tissue (eg, mass anterior to the rectum). However, unlike this patient, they usually have minimal axillary or pubic hair due to androgen resistance. (Choice B) Asherman syndrome, the development of intrauterine adhesions, can obstruct uterine outflow and cause abdominopelvic pain and amenorrhea (typically secondary amenorrhea). However, patients usually have a history of uterine infection or intrauterine surgery (eg, dilation and curettage), and there is no association with a palpable mass on digital rectal examination. (Choice C) Endometriosis, the ectopic implantation of endometrium outside the uterus, can cause worsening, cyclic abdominopelvic pain and rectovaginal nodularity (eg, endometrial implants in the pouch of Douglas) that may be palpable on digital rectal examination. However, endometriosis is not associated with amenorrhea. (Choice E) Kallmann syndrome can present with primary amenorrhea due to the impaired synthesis of gonadotropin-releasing hormone in the hypothalamus; therefore, in contrast to this patient with normal secondary sexual characteristics, those with Kallmann syndrome typically have no secondary sexual characteristics. Educational objective: Adolescent girls with primary amenorrhea, normal secondary sexual characteristics, and progressively worsening abdominopelvic pain may have an imperforate hymen. Examination typically shows a smooth vaginal bulge (hematocolpos) and a palpable mass anterior to the rectum.

A 15-Year-Old Girl Comes to the Office Due to Pelvic