In a patient with uterine fibroids and a history of excessive uterine bleeding who now has an elevated red cell mass, what diagnostic workup and management should be undertaken?

Diagnostic Workup and Management of Elevated Red Cell Mass in a Patient with Uterine Fibroids and Excessive Bleeding

This patient requires immediate evaluation for Myomatous Erythrocytosis Syndrome (MES), a rare but serious condition where large uterine fibroids produce ectopic erythropoietin, causing secondary polycythemia despite chronic bleeding. 1, 2

Initial Diagnostic Workup

Critical Laboratory Tests

• Complete blood count with differential - Confirm elevated hemoglobin/hematocrit (typically Hgb >17 g/dL, Hct >52%)
• Serum erythropoietin level - Will be elevated in MES (unlike primary polycythemia vera)
• JAK-2 mutation testing - Must be negative to exclude polycythemia vera
• Iron studies - Paradoxically may show normal or elevated iron despite bleeding history
• Arterial oxygen saturation - Rule out hypoxia-driven erythrocytosis

Imaging Assessment

• Transvaginal ultrasound is the first-line imaging modality to characterize fibroid size, number, and location 3, 4
• MRI pelvis with diffusion-weighted imaging if:
  • Ultrasound cannot completely visualize the uterus/endometrium
  • Fibroids are very large (>10 cm)
  • Surgical planning is needed
  • Need to differentiate from leiomyosarcoma 3, 4

Key imaging finding in MES: Fibroids are typically very large (often >20 cm) with markedly increased vascularity 1, 2

Understanding the Paradox

This clinical scenario represents a diagnostic paradox: chronic uterine bleeding should cause anemia, not erythrocytosis. When you encounter elevated red cell mass in a patient with bleeding fibroids, MES must be your primary consideration. In the largest case series, 85% of MES patients had progressive abdominal mass enlargement, 65% had pelvic pain, and only 35% reported abnormal bleeding 2. The erythrocytosis occurs because large fibroids produce erythropoietin, which activates the JAK-2 pathway and drives red blood cell production that overwhelms the losses from bleeding 1.

Management Strategy

Preoperative Preparation (Critical for Safety)

Before any surgical intervention, you must reduce thromboembolic risk:

• Low-molecular-weight heparin prophylaxis
• Aggressive intravenous hydration to reduce blood viscosity
• Consider phlebotomy if hematocrit >60% to reduce thrombotic risk 1

Definitive Treatment

Hysterectomy is the definitive treatment for MES and provides complete resolution of erythrocytosis in 100% of cases with available follow-up 2. Erythrocytosis normalizes within 2-6 weeks post-hysterectomy 1, 2.

Myomectomy can be considered if fertility preservation is desired, but carries significant risks:

• Substantially increased fibroid vascularity leads to massive intraoperative bleeding
• High risk of severe postoperative hemorrhage (up to 1800 mL/24 hours reported) 1
• May require reoperation for hemostasis
• Erythrocytosis will resolve if all fibroid tissue is removed 1

Alternative Approaches (If Surgery Contraindicated)

If the patient refuses surgery or has prohibitive surgical risk:

1. Uterine artery embolization (UAE) - May reduce fibroid size and erythropoietin production, though no specific data exists for MES 5

2. Medical management is NOT definitive for MES but can temporize:

   • First-line: Progestin-containing IUD or combined oral contraceptives for bleeding control 5
   • Second-line: GnRH antagonists (relugolix, elagolix) with add-back therapy to reduce fibroid volume 5
   • Tranexamic acid for bleeding episodes 5

Critical Perioperative Complications

Thromboembolism Risk

The hyperviscosity from erythrocytosis creates extreme thrombotic risk. Maintain prophylactic anticoagulation throughout the perioperative period 1.

Hemorrhage Risk

Despite the erythrocytosis, these patients face paradoxical massive bleeding risk due to:

• Markedly increased uterine and fibroid vascularity
• Large fibroid size requiring extensive dissection
• Potential for delayed postoperative hemorrhage 1

Prepare for massive transfusion protocol availability and have interventional radiology on standby for potential uterine artery embolization if hemorrhage occurs.

Follow-Up

• Hemoglobin/hematocrit monitoring at 2,4, and 6 weeks post-surgery
• Expect normalization by 6 weeks; persistent erythrocytosis suggests incomplete fibroid removal or alternative diagnosis 1, 2
• Pathology confirmation of leiomyoma (not leiomyosarcoma) is essential 1

Common Pitfalls to Avoid

1. Assuming anemia based on bleeding history without checking CBC - this delays MES diagnosis
2. Proceeding to surgery without hematologic workup - risks catastrophic thromboembolism
3. Inadequate preoperative anticoagulation - MES patients have suffered fatal pulmonary emboli
4. Underestimating bleeding risk - the increased vascularity is dramatic and unexpected
5. Attempting conservative management when hysterectomy is appropriate - MES does not respond to medical therapy alone