LAUSR

Rationale: Aggressive angiomyxoma (AAM) is a rare mesenchymal tumor primarily involving the lower genital tract of reproductive females. It often shares pathologic morphology with other mesenchymal lesions, which result in diagnostic difficulties for pathologists. Patient concerns and diagnoses: We described the case of a 32-year-old female presenting with a pelvic mass. Imaging examination showed a “swirling sign” within the mass. The mass was 10.2 × 10 × 7.7 cm, located in the right front of the uterus, with unclear demarcation from the surrounding organs and tissues. The gross appearance was grayish brown with a solid section and a myxedematous cut surface. Microscopically, it was a mesenchymal tumor with a presence of perivascular smooth muscle fibers radiating from the blood vessel and an infiltrative growth pattern. The pelvic AAM was diagnosed based on clinicopathologic and imaging features. Interventions and outcomes: A surgery with local excision of the mass was performed. The patient experienced 1 relapse during 2-year follow-up and underwent the radiation therapy. Lessons: When the pathological morphology of AAM overlaps with other mesenchymal lesions, the comprehensive understanding of tumor clinicopathological characteristics combined with imaging features is important for the accurate diagnosis of AAM.