A 35-year-old woman from Mumbai presents with a 3-month history of prolonged, heavy menstrual bleeding (12–14 days per cycle) with passage of large clots. She denies dysmenorrhea or intermenstrual bleeding. Pelvic examination is unremarkable with a normal-sized uterus. Transvaginal ultrasound shows a thickened endometrium (14 mm) with heterogeneous echotexture and small cystic spaces within the myometrium. Hemoglobin is 9.1 g/dL. Coagulation studies and thyroid function are normal. What is the most likely diagnosis?

Explanation

## Clinical Diagnosis: Adenomyosis ### Key Findings **Key Point:** The combination of prolonged heavy menstrual bleeding, a normal-sized uterus on examination, and a heterogeneous thickened endometrium with small myometrial cystic spaces (adenomyotic cysts) on ultrasound is diagnostic of adenomyosis. ### Pathophysiology of Adenomyosis Adenomyosis is characterized by: 1. **Ectopic endometrial glands and stroma** invading the myometrium (>2.5 mm depth) 2. **Abnormal myometrial contractility** and increased prostaglandin production 3. **Increased myometrial vascularity** with impaired hemostasis 4. **Junctional zone abnormalities** visible on advanced imaging ### Diagnostic Criteria: Adenomyosis vs. Fibroids vs. Hyperplasia | Feature | Adenomyosis | Fibroids | Endometrial Hyperplasia | | --- | --- | --- | --- | | **Uterine size** | Normal or uniformly enlarged (≤12 cm) | Enlarged, irregular, nodular | Normal | | **Uterine consistency** | Boggy, tender, soft | Firm, irregular, nodular | Normal | | **Endometrial thickness** | Thickened (≥12 mm), heterogeneous | Normal or distorted | Thickened (≥4 mm), uniform | | **Myometrial appearance** | Heterogeneous, adenomyotic cysts, junctional zone abnormality | Discrete hypoechoic/isoechoic masses | Normal | | **Age group** | 40–50 years (can occur earlier) | 35–50 years | 40–60 years | | **Dysmenorrhea** | Present (progressive) | Absent or mild | Absent | | **Bleeding pattern** | Prolonged HMB, regular cycles | Heavy HMB, regular cycles | Irregular, prolonged, heavy | | **Diagnosis** | Imaging + clinical; confirmed by hysterectomy pathology | Imaging (ultrasound/MRI) | Endometrial biopsy/D&C | **High-Yield:** Adenomyosis is confirmed only on hysterectomy pathology, but transvaginal ultrasound with junctional zone abnormalities and adenomyotic cysts is >80% sensitive and specific. ### Ultrasound Features of Adenomyosis ```mermaid flowchart TD A[Adenomyosis on Ultrasound]:::outcome --> B[Junctional Zone Abnormality]:::action A --> C[Adenomyotic Cysts]:::action A --> D[Heterogeneous Myometrium]:::action A --> E[Thickened Endometrium]:::action B --> F[Irregular, indistinct junctional zone]:::outcome C --> G[Small cystic spaces in myometrium]:::outcome ``` **Clinical Pearl:** The presence of **small cystic spaces within the myometrium** (adenomyotic cysts) is highly specific for adenomyosis and distinguishes it from fibroids, which show discrete hypoechoic masses. ### Management 1. **Medical (first-line):** NSAIDs, tranexamic acid, combined oral contraceptives, progestins (levonorgestrel IUS, medroxyprogesterone) 2. **Surgical (if refractory):** Hysterectomy (definitive); endometrial ablation (less effective in adenomyosis) **Mnemonic:** **ADENOMYOSIS = Abnormal Dysmenorrhea + Enlarged Nodular Ominous Myometrium + Young-to-Old age + Osis (invasion)** ### Why This Patient Has Adenomyosis - Age 35 (adenomyosis can present earlier, especially in multiparous women) - **Normal-sized uterus** (rules out fibroids) - **Prolonged HMB with regular cycles** (classic presentation) - **Thickened, heterogeneous endometrium** (≥12 mm) - **Adenomyotic cysts** (small myometrial cystic spaces) - Normal coagulation and thyroid function (excludes systemic causes) - **No dysmenorrhea mentioned**, but adenomyosis can present without it **Citation:** Garcia-Solares J, et al. Pathogenesis of uterine adenomyosis: an update. Fertil Steril. 2018; also Park 26e Ch 10.