Tumor-simulating retrorectal heterotopia of bone marrow

Area of Science:

• Hematology
• Pathology
• Surgical Oncology

Background:

• Extramedullary hematopoiesis (EMH) is the formation of blood cells outside the bone marrow.
• Retrorectal masses can present diagnostic challenges, potentially mimicking neoplastic conditions.

Observation:

• A 40-year-old woman presented with uterine bleeding and was found to have a retrorectal mass.
• The mass was diagnosed as extramedullary hematopoiesis.
• The patient had iron deficiency anemia, which was corrected post-operatively.

Findings:

• The retrorectal mass of extramedullary hematopoiesis was completely excised.
• The patient remained disease-free with no hematologic abnormalities six years post-surgery.
• Wright's-stained imprints confirmed trilineage hematopoiesis within the mass.

Implications:

• This case suggests heterotopic marrow formation as a potential cause of retrorectal masses.
• Recognizing EMH is crucial for accurate diagnosis and appropriate management of retrorectal masses.
• Surgical excision can be an effective treatment for symptomatic EMH presenting as a mass.