Uterine inflammatory myofibroblastic tumor

Area of Science:

• Oncology
• Pathology
• Genetics

Background:

• Inflammatory myofibroblastic tumor (IMT) is a neoplasm of unknown cause, often linked to ALK gene abnormalities.
• Uterine IMTs are rare, challenging to diagnose due to histological overlap with other tumors.
• Existing data primarily comes from case reports and small series, necessitating comprehensive reviews.

Purpose of the Study:

• To comprehensively review and describe the characteristics of uterine inflammatory myofibroblastic tumors.
• To highlight the diagnostic challenges and the importance of ALK gene analysis.
• To identify factors associated with an aggressive clinical course.

Main Methods:

• Comprehensive literature review of uterine inflammatory myofibroblastic tumors.
• Analysis of diagnostic criteria, clinical presentation, and histopathological features.
• Review of ALK gene status and associated fusion partners.

Main Results:

• Uterine IMTs present across a wide age range (median 39 years) with symptoms similar to leiomyomas.
• IMTs constitute a small percentage of leiomyomas (0.1%) but are more frequent in pregnant women (10%) and STUMP (14%).
• ALK positivity is common, with TIMP3 fusions prevalent in pregnancy-associated cases; aggressive features include older age, larger size, and specific histological findings.

Conclusions:

• Systematic ALK immunohistochemistry is crucial for tumors excised during pregnancy, STUMPs, and leiomyosarcomas.
• ALK abnormalities represent a targetable feature in IMTs.
• Approximately 25% of patients experience an aggressive course, associated with specific clinical and pathological indicators.