A 35-year-old woman from Mumbai presents with progressive menorrhagia over 3 years. She reports heavy, prolonged menses (8–9 days) with severe dysmenorrhea. On examination, the uterus is diffusely enlarged, boggy, and tender. Pelvic ultrasound shows a heterogeneous, thickened myometrium (>12 mm) with poor definition of the endometrial–myometrial interface. Serum β-hCG is negative. Endometrial biopsy shows basalis layer invasion. What is the most likely diagnosis?

Explanation

## Diagnosis: Adenomyosis ### Clinical Presentation **Key Point:** Adenomyosis is characterized by the triad of menorrhagia, dysmenorrhea, and a diffusely enlarged, boggy, tender uterus in women aged 30–50 years. ### Pathophysiology 1. **Definition:** Ectopic endometrial glands and stroma invade the myometrium (>2.5 mm depth from endometrial–myometrial junction) 2. **Mechanism of bleeding:** - Disrupted endometrial–myometrial interface → abnormal hemostasis - Increased local prostaglandins and vasopressin resistance - Impaired myometrial contractility - Increased angiogenesis and vascular fragility 3. **Mechanism of pain:** Increased uterine peristalsis and myometrial contractions due to elevated oxytocin receptors ### Diagnostic Criteria **High-Yield:** Adenomyosis diagnosis requires histopathology (endometrial biopsy or hysterectomy specimen) showing invasion of basalis layer endometrium into myometrium. | Finding | Adenomyosis | |---------|-------------| | **Uterine size** | Diffusely enlarged (usually <14 cm) | | **Uterine texture** | Boggy, tender, soft | | **Ultrasound** | Heterogeneous myometrium, poor endo-myometrial interface, junctional zone >12 mm | | **MRI** | Best imaging modality; shows junctional zone abnormality, myometrial heterogeneity | | **Histology** | Basalis layer invasion, increased endometrial glands/stroma in myometrium | | **Cycle pattern** | Regular or irregular | | **Age** | Typically 40–50 years (but can occur earlier) | **Clinical Pearl:** Adenomyosis is often called the "disease of the perimenopausal woman," but it is increasingly recognized in younger women, especially those with prior uterine instrumentation (D&C, curettage, hysteroscopic procedures). ### Imaging Hierarchy 1. **Transvaginal ultrasound (TVS):** First-line imaging; sensitivity 60–90% depending on operator and adenomyosis severity 2. **MRI:** Gold standard for diagnosis; superior soft-tissue contrast; sensitivity >90% 3. **Hysterosalpingography or hysteroscopy:** Not diagnostic but may show irregular endometrial cavity **Mnemonic:** **ADENOMYOSIS** = **A**bnormal **D**ysmenorrhea, **E**ctopic **N**ormal endometrium **O**ccupying **M**yometrium, **Y**oung-to-old women, **O**pen **S**pace (poor junctional zone definition), **I**nvasion **S**hown on histology ### Why Not Leiomyomas? **Warning:** While adenomyosis and fibroids can coexist, the key distinction is: - **Fibroids:** Discrete, hypoechoic masses; uniformly enlarged, firm uterus - **Adenomyosis:** Diffuse, heterogeneous myometrial involvement; boggy, tender uterus; poor endo-myometrial interface The clinical presentation and imaging findings here are classic for adenomyosis alone.