What are the next steps for a patient who had an endometrial ablation and now presents with an irregular uterine contour, hypodensities, calcifications, and free fluid in the pelvis on computed tomography (CT) scan, as well as a possible small leiomyoma on ultrasound?

Post-Endometrial Ablation Complications: Evaluation and Management

This patient requires urgent gynecologic consultation and pelvic MRI with diffusion-weighted imaging to evaluate for post-ablation complications, specifically hematometra, adenomyosis, or endometrial carcinoma, given the concerning constellation of irregular uterine contour, pelvic free fluid, and calcifications.

Immediate Clinical Assessment

Endometrial sampling is mandatory in this patient despite prior ablation, as the presence of free pelvic fluid combined with irregular uterine contour raises concern for:

• Hematometra (fluid collection within the uterine cavity from obstructed outflow) 1
• Residual functioning endometrium that could harbor malignancy 1, 2
• Post-ablation endometrial syndrome 2

The CT findings of hypodensities, calcifications, and free fluid are not typical benign post-ablation changes and warrant aggressive investigation 1.

Recommended Diagnostic Algorithm

Step 1: Pelvic MRI with Specific Protocol

Order pelvic MRI with diffusion-weighted imaging immediately 3:

• MRI provides superior soft-tissue characterization compared to CT and can visualize the endometrium even in the presence of leiomyomas and post-ablation changes 3
• Diffusion-weighted imaging improves sensitivity and specificity for detecting endometrial pathology and can help differentiate leiomyosarcoma from benign leiomyoma 3
• MRI can identify hematometra, residual endometrial islands, and adenomyosis with high accuracy 1, 2

Step 2: Endometrial Sampling

Perform endometrial biopsy or hysteroscopy with directed sampling 4, 5:

• Post-ablation patients can still develop endometrial hyperplasia or carcinoma in residual endometrial tissue 1, 2
• Transvaginal ultrasound showing endometrial tissue or MRI confirming endometrial lining necessitates tissue diagnosis 4, 1
• Hysteroscopy allows direct visualization and is preferred over blind biopsy in post-ablation patients 6

Step 3: Evaluate for Specific Post-Ablation Complications

Assess for hematometra:

• Occurs in symptomatic post-ablation patients when cervical stenosis or endometrial scarring obstructs menstrual outflow 1
• Sonography can identify hematometra, though MRI provides better characterization 1
• Free pelvic fluid on CT may represent retrograde menstruation or uterine perforation 1

Evaluate for adenomyosis:

• Found in 40% of hysterectomies performed after failed endometrial ablation 2
• Adenomyosis is a common cause of persistent bleeding and pain post-ablation 2
• MRI is superior for diagnosing adenomyosis with characteristic junctional zone thickening 3

Consider leiomyosarcoma differentiation:

• While the ultrasound suggests a small leiomyoma, calcifications in a fibroid can represent either benign involution or rarely malignant degeneration 7
• Diffusion-weighted MRI helps differentiate leiomyosarcoma from benign leiomyoma 3

Critical Pitfalls to Avoid

Do not assume all post-ablation findings are benign:

• Endometrial ablation does not eliminate cancer risk; residual endometrial islands can undergo malignant transformation 1, 2
• Hysterectomies performed months to years after ablation show persistent endometrial lining in many cases 2

Do not rely on ultrasound alone:

• Post-ablation changes including fibrosis, necrosis, and scarring limit ultrasound visualization 3, 1
• CT is inadequate for characterizing endometrial pathology and should not guide management 3

Do not delay evaluation of free pelvic fluid:

• Free fluid in a post-ablation patient is abnormal and may indicate hematometra with retrograde flow, infection, or perforation 1
• This finding combined with irregular uterine contour requires urgent investigation 3

Expected Histologic Findings Post-Ablation

If hysterectomy becomes necessary, anticipate:

• Necrotic tissue of myometrial origin (28% of cases) 2
• Fibrosis and vascular changes, particularly in the first year post-ablation 2
• Zonation effect with variable tissue destruction 2
• Adenomyosis (40%) or extensive leiomyomas (12%) 2
• Residual endometrial lining, especially in hysterectomies performed >13 months post-ablation 2

Timing Considerations

The interval since ablation matters:

• Hysterectomies performed early (<5 months) show more prominent fibrosis 2
• Later hysterectomies (>13 months) more frequently show residual endometrial lining 2
• This patient's "few years" post-ablation status increases likelihood of residual functioning endometrium requiring evaluation 2

Definitive Management Options

If malignancy is excluded and symptoms persist:

• Repeat endometrial ablation can be considered but carries increased complication risk and should only be performed hysteroscopically with direct visualization 6
• Hysterectomy provides definitive resolution and is performed in 25-40% of patients within 5 years of initial ablation 8
• The presence of adenomyosis or extensive leiomyomas favors hysterectomy over repeat ablation 2