Submucosal Fibroid (Answer D)
The most likely diagnosis is a submucosal fibroid, given the combination of prolonged heavy menstrual bleeding (menorrhagia) with pelvic pressure and bloating in this 42-year-old woman. 1
Clinical Reasoning Based on Symptom-Location Correlation
The key to this diagnosis lies in understanding which fibroid location causes which symptoms:
Heavy Menstrual Bleeding Points Specifically to Submucosal Location
Submucosal fibroids are specifically and strongly associated with menorrhagia because they project into the uterine cavity and directly affect the endometrial surface. 1
These fibroids cause abnormal uterine bleeding through multiple mechanisms including enlargement of the uterine cavity, impairment of blood supply to the endometrium, and endometrial atrophy and ulceration. 1
Menorrhagia is the most frequent symptom of uterine fibroids overall, often resulting in iron deficiency anemia. 2
Transvaginal ultrasound has excellent diagnostic accuracy for submucosal fibroids specifically, with 90% sensitivity and 98% specificity. 1, 3, 4
Why the Other Options Are Less Likely
Subserosal fibroids (Option C):
- Subserosal fibroids typically do not cause menorrhagia, but are more associated with bulk symptoms such as pelvic pressure alone. 1, 3
- While this patient has pelvic pressure, the dominant feature of prolonged heavy menstrual bleeding makes subserosal location unlikely. 1
Cervical fibroids (Option A):
- Cervical fibroids are rare, accounting for less than 5% of all uterine fibroids. 3
- They more commonly present with dyspareunia, urinary obstruction, or vaginal discharge rather than heavy menstrual bleeding. 3
- They have high treatment failure rates with interventions like uterine artery embolization and are not characteristically associated with menorrhagia as a primary presenting symptom. 1
Parasitic fibroids (Option B):
- Parasitic fibroids are extremely rare and represent fibroids that have detached from the uterus and obtained blood supply from other structures. 5
- They are commonly diagnosed as incidental findings during radiologic or surgical procedures, not as a cause of menorrhagia. 5
- This diagnosis would not explain the heavy menstrual bleeding pattern. 5
Diagnostic Confirmation
The ultrasound should be reviewed to confirm whether the fibroid distorts the endometrial cavity—this is the hallmark of submucosal location. 3
Intramural fibroids that abut the endometrium can cause menorrhagia, but the bleeding is typically less severe than that produced by true submucosal lesions. 3