A 32-year-old Indian woman presents with severe dysmenorrhea and chronic pelvic pain for the past 3 years. She reports that pain begins 1–2 days before menstruation and persists throughout her cycle, worsening during menses. On examination, the uterus is uniformly enlarged, tender, and boggy. Transvaginal ultrasound shows a heterogeneous myometrium with ill-defined junctional zones and small cystic spaces within the myometrium. Her serum CA-125 is mildly elevated at 42 U/mL. What is the most likely diagnosis?

Explanation

## Diagnosis: Adenomyosis ### Clinical Presentation **Key Point:** Adenomyosis classically presents with **secondary dysmenorrhea** (pain that develops after years of pain-free menses) and **chronic pelvic pain** that worsens during menstruation. The pain typically begins days before menses and continues throughout the cycle. ### Physical Examination Findings **Clinical Pearl:** On bimanual examination, the uterus is: - Uniformly and symmetrically enlarged (typically 12–14 weeks size) - Tender and boggy - Mobile (unlike fibroids, which may be fixed) - Diffuse enlargement (not nodular) This patient's **uniformly enlarged, tender, boggy uterus** is pathognomonic for adenomyosis. ### Imaging Features **High-Yield:** Transvaginal ultrasound findings in adenomyosis include: - Heterogeneous myometrium - **Ill-defined junctional zone** (>12 mm thickness or poor definition) - Small cystic spaces within the myometrium (adenomyotic cysts) - Asymmetric myometrial thickening MRI is the gold standard (T2-weighted shows low-signal junctional zone with high-signal foci), but TVS is first-line. ### Laboratory **Key Point:** Serum CA-125 may be mildly elevated (>35 U/mL) in adenomyosis, but is neither sensitive nor specific. It is more commonly elevated in endometriosis. ### Pathophysiology Adenomyosis results from **invagination of basalis layer endometrium into the myometrium**, causing: - Myometrial hyperplasia and hypertrophy - Increased prostaglandin production → dysmenorrhea - Abnormal uterine peristalsis - Altered junctional zone contractility ### Differential Diagnosis | Feature | Adenomyosis | Endometriosis | Fibroid | |---------|-------------|---------------|--------| | **Uterine size** | Uniformly enlarged | Normal or slightly enlarged | Nodular, asymmetric | | **Uterine consistency** | Boggy, tender | Normal or tender | Firm, hard | | **Pain pattern** | Dysmenorrhea + chronic pelvic pain | Dyspareunia, cyclic pain, infertility | Usually asymptomatic | | **Junctional zone** | Ill-defined, thickened | Normal | Normal | | **Imaging** | Heterogeneous myometrium | Ovarian cysts, peritoneal lesions | Well-defined mass | | **CA-125** | Mildly elevated | Often markedly elevated | Normal | **Warning:** Do not confuse adenomyosis (endo**my**osis = within myometrium) with endometriosis (endo**met**riosis = outside uterus, typically on peritoneum and ovaries). ### Definitive Diagnosis **Key Point:** Histopathology is the gold standard: presence of endometrial glands and stroma **within the myometrium** (beyond the junctional zone) with surrounding myometrial hyperplasia.