Endometriosis

Summary

Endometriosis is a complex, estrogen-driven condition marked by ectopic endometrial tissue leading to chronic pain, infertility, and multi-organ involvement. Early diagnosis through clinical suspicion and imaging, followed by tailored medical or surgical treatment, is essential to improve quality of life and preserve fertility.

Definition

Endometriosis is a chronic, estrogen-dependent condition characterized by the presence of endometrial-like tissue outside the uterine cavity. These ectopic implants commonly involve pelvic organs such as the ovaries, fallopian tubes, and peritoneum, but may also affect extrapelvic sites including the bowel, bladder, diaphragm, and, rarely, the lungs. The ectopic endometrial tissue responds to cyclic hormonal changes, leading to inflammation, pain, and fibrosis, and is a major contributor to infertility in women of reproductive age.

Epidemiology

• Age of onset: Typically between 20 and 40 years

• Prevalence: Estimated to affect 2–10% of women of reproductive age

• Diagnosis: Often delayed by several years due to variability in presentation

• Ethnicity: No clear ethnic predilection, though access to diagnosis and treatment may differ globally

Etiology and Pathophysiology

The exact cause of endometriosis remains unclear, though multiple theories exist:

• Retrograde menstruation: Endometrial cells flow backward through the fallopian tubes and implant in the pelvis.

• Coelomic metaplasia: Peritoneal cells transform into endometrial-like cells under hormonal influence.

• Lymphatic or hematogenous spread: Dissemination of endometrial tissue to distant sites.

• Iatrogenic implantation: Transfer during gynecological procedures.

• Genetic predisposition: Family history increases risk.
  

Once implanted, ectopic endometrial tissue proliferates under estrogenic stimulation, provoking chronic inflammation, angiogenesis, and fibrosis. Over time, this leads to adhesions, anatomical distortion, and potential compromise of organ function.

Risk Factors

• Early menarche

• Late menopause

• Nulliparity

• Short menstrual cycles (<27 days)

• Heavy or prolonged menstrual bleeding

• Family history of endometriosis

• Congenital uterine or tubal anomalies
  

Common Sites of Involvement

• Pelvic organs: Ovaries (aka; chocolate cyst, most common), uterus, fallopian tubes, uterosacral ligaments, pouch of Douglas

• Urinary tract: Bladder, ureters

• Gastrointestinal tract: Rectum, sigmoid colon

• Extrapelvic sites (rare): Diaphragm, abdominal wall, lungs

Clinical Features

• While up to 25% of individuals may be asymptomatic, typical symptoms include:

• On a physical exam, findings may include adnexal tenderness, uterosacral ligament nodularity, fixed retroverted uterus, or adnexal masses.

Diagnosis

Imaging

• Transvaginal ultrasound (TVUS): First-line imaging to identify endometriomas or deep pelvic involvement

• MRI pelvis: Used when ultrasound is inconclusive or deep infiltrating disease is suspected

Laparoscopy

• Gold standard for diagnosis

• Allows direct visualization and biopsy of lesions

• Typical findings include “powder-burn” lesions, adhesions, and chocolate cysts (endometriomas)

Histology

Endometrial glands and stroma with hemosiderin-laden macrophages confirm diagnosis

Management

Medical Treatment

• Note: Medical therapy is effective for pain but does not improve fertility.

Surgical Treatment

• Laparoscopic excision or ablation: Indicated in refractory cases or for infertility

• Definitive surgery (hysterectomy with/without salpingo-oophorectomy): Reserved for severe cases with no desire for future fertility

Complications

• Infertility: Due to adhesions, distorted anatomy, or tubal dysfunction

• Chronic pelvic pain

• Adhesions and organ entrapment: Bowel obstruction, urinary retention

• Ectopic pregnancy: Increased risk due to tubal involvement

• Ovarian cancer: Slightly elevated risk, particularly with long-standing disease