A 28-year-old Indian woman presents with severe dyspareunia and infertility of 2 years duration. She reports cyclic pelvic pain that is worse during menstruation and radiates to the lower back. On examination, the uterus is normal-sized and mobile. Transvaginal ultrasound reveals a 4 cm left ovarian cyst with internal echoes and a retroverted uterus with peritoneal adhesions. Diagnostic laparoscopy shows multiple peritoneal implants, chocolate cysts on both ovaries, and dense adhesions involving the bowel. What is the most likely diagnosis?

Explanation

## Diagnosis: Endometriosis ### Clinical Presentation **Key Point:** Endometriosis is characterized by the **triad of dyspareunia, dysmenorrhea, and infertility**. Pain is typically **cyclic** and worsens during menstruation. Infertility affects 30–50% of women with endometriosis. ### Pathophysiology Endometriosis is the presence of **ectopic endometrial glands and stroma outside the uterus**, most commonly on: - Ovaries (most frequent site) - Peritoneum (peritoneal surface) - Pouch of Douglas - Bowel and other pelvic organs **Mnemonic: SAMPSON** — Sampson's theory of retrograde menstruation (menstrual blood flows backward through fallopian tubes into the peritoneal cavity). ### Clinical Features | Feature | Endometriosis | |---------|---------------| | **Dyspareunia** | Deep dyspareunia (pain with deep penetration) — hallmark | | **Dysmenorrhea** | Cyclic, begins days before menses, worsens during period | | **Infertility** | 30–50% of women with endometriosis are infertile | | **Pelvic pain** | Chronic, cyclic, radiating to lower back and legs | | **Uterine size** | Normal or slightly enlarged | | **Uterine consistency** | Normal or tender | | **Nodularity** | Uterosacral ligaments may be nodular and tender | ### Imaging Findings **High-Yield:** Transvaginal ultrasound in endometriosis: - **Ovarian endometriomas** ("chocolate cysts") — cysts with homogeneous low-level echoes - Retroverted uterus (common) - Peritoneal adhesions - Pouch of Douglas obliteration **Clinical Pearl:** The presence of **bilateral ovarian cysts with internal echoes** (chocolate cysts) is highly suggestive of endometriosis. ### Laparoscopic Findings (Gold Standard) **Key Point:** Diagnostic laparoscopy is the gold standard for endometriosis diagnosis. Findings include: - **Peritoneal implants** (red, white, or black lesions) - **Chocolate cysts** (endometriomas) on ovaries - **Dense adhesions** involving bowel, ovaries, and peritoneum - Pouch of Douglas obliteration - Nodular uterosacral ligaments ### Staging (rASRM Classification) **High-Yield:** Endometriosis is staged I–IV based on extent of disease: - **Stage I (Minimal):** Superficial peritoneal lesions, small ovarian cysts - **Stage II (Mild):** Deeper peritoneal involvement, larger ovarian cysts - **Stage III (Moderate):** Multiple implants, significant adhesions - **Stage IV (Severe):** Extensive disease, dense adhesions, large endometriomas This patient's findings (bilateral chocolate cysts + dense adhesions + peritoneal implants) suggest **Stage III–IV disease**. ### Differential Diagnosis | Feature | Endometriosis | Adenomyosis | Ovarian Cancer | TB | |---------|---------------|-------------|----------------|----| | **Dyspareunia** | Deep dyspareunia (yes) | No | No | No | | **Uterine size** | Normal | Uniformly enlarged, boggy | N/A | Normal | | **Ovarian cysts** | Endometriomas (chocolate) | None | Solid/cystic, irregular | Ascites | | **Peritoneal implants** | Yes | No | Possible | Adhesions, ascites | | **CA-125** | Often elevated (>35) | Mildly elevated | Markedly elevated (>200) | Normal/mild | | **Laparoscopy** | Peritoneal lesions, adhesions | N/A | Malignant cells | Caseating granulomas | **Warning:** Do not confuse adenomyosis (within myometrium, uniformly enlarged uterus) with endometriosis (ectopic lesions outside uterus, normal-sized uterus). ### Management **Key Point:** First-line treatment for endometriosis: 1. **NSAIDs** for pain management 2. **Hormonal contraceptives** (continuous or cyclic) to suppress ovulation 3. **Progestins** (oral, injectable, or intrauterine) to induce endometrial atrophy 4. **GnRH agonists** for severe disease or inadequate response to hormonal therapy 5. **Surgical excision/ablation** for stage III–IV disease or infertility