Differentials
Adenomyosis
SIGNS / SYMPTOMS
Symptoms may be identical to those of endometriosis.
INVESTIGATIONS
Preoperative MRI findings may show diffuse or focal widening of the junctional zone (inner myometrium), islands of endometrial tissue or cystic dilation of glands or hemorrhage, linear striations radiating out from the endometrium into the myometrium, mass within the myometrium (adenomyoma).
Laparoscopy may reveal a normal pelvis or concurrent endometriosis.
Histopathologic evaluation of the uterus after hysterectomy shows endometrial glands/stroma in the myometrium.
Interstitial cystitis
SIGNS / SYMPTOMS
Symptoms primarily localized to the bladder, such as urinary frequency and urgency. Women complain of pain with a full bladder that is relieved upon voiding.
Diffuse chronic pain and dyspareunia are common and often indistinguishable from endometriosis.
INVESTIGATIONS
Cystoscopy with hydrodistention shows glomerulations (pinpoint mucosal hemorrhages) and Hunner ulcers as distention medium is released.
Potassium chloride sensitivity test: after instilling a dilute solution of potassium chloride into the bladder with a catheter, the woman will note a change in urinary urgency and frequency scores.
Pelvic inflammatory disease (PID)
SIGNS / SYMPTOMS
Fever, nausea, acute pain along with malodorous vaginal discharge and cervical motion tenderness/adnexal tenderness is typical for acute PID.
Chronic PID may be indistinguishable from endometriosis.
INVESTIGATIONS
Cervical cultures for Neisseria gonorrhea or Chlamydia trachomatis may be positive.
Pelvic ultrasonography may show complex adnexal masses as distinguished from homogeneous, low-level echoes typically seen with endometrioma.
Irritable bowel syndrome
SIGNS / SYMPTOMS
Change in bowel habits (alternating constipation and diarrhea; bloating) may help differentiate. Dyschezia more typical of endometriosis.
INVESTIGATIONS
Diagnosis is usually clinical and based on an absence of ultrasound, MRI or laparoscopic findings of endometriosis.
Ovarian cyst (benign)
SIGNS / SYMPTOMS
May be asymptomatic with an incidental pelvic mass or present with acute rather than chronic pain, such as in the case of hemorrhagic cysts.
INVESTIGATIONS
Transvaginal ultrasound: enlarged ovary with a simple or complex cystic structure emanating from the ovary as distinguished from homogeneous, low-level echoes typically seen with endometrioma. Ultrasound is ideal for differentiating liquid from solid material.
Ovarian cancer, epithelial
SIGNS / SYMPTOMS
Typical symptoms represent advanced-stage cancer, and include weight gain despite lack of appetite, increased abdominal girth and altered bowel habits.
Endometriosis may be an uncommon risk factor for developing epithelial ovarian cancer.
INVESTIGATIONS
Transvaginal ultrasound: complex adnexal mass (solid and cystic) with multiple loculations or thick septa; ascites. Most women present with advanced-stage disease.
Histopathology: there are many cell types and various stains can be used to verify/differentiate.
Pelvic floor tension myalgia
SIGNS / SYMPTOMS
May be unable to differentiate clinically.
Clinically, women have chronic pelvic pain and dyspareunia (or inability to have intercourse due to spasm and pain).
An experienced clinician can elicit focal spasm and tenderness on pelvic and rectovaginal exam.
INVESTIGATIONS
No diagnostic test available. Lack of positive findings on other investigations.
Neuropathic pain
SIGNS / SYMPTOMS
Burning, shock-like pain associated with paresthesia or dysesthesia.
INVESTIGATIONS
No diagnostic test available. Lack of positive findings on other investigations.
Uterine myoma (fibroids)
SIGNS / SYMPTOMS
Many are asymptomatic, but often present with heavy and/or irregular menstrual bleeding.
Pelvic exam may show an enlarged, nodular pelvic mass that can vary in size and shape.
INVESTIGATIONS
Transvaginal ultrasound: concentric, solid, hypoechoic (dark) mass or masses within the endometrium (submucosal), myometrium (intramural) or external (subserosal). Small myoma may be isoechoic, but if calcified, myoma can also appear hyperechoic (bright).
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