Diagnostic overlap between necrotic leiomyoma, adenomyoma and uterine sarcoma: an ultrasound challenge

Atypical myometrial lesions may represent a significant diagnostic challenge even for experienced sonographers, particularly when ultrasound and MRI findings overlap among benign, borderline, and malignant entities. Reporting these cases may contribute to improving pattern recognition and refining the diagnostic work-up in clinical practice. We report the case of a 47-year-old woman presenting with menometrorrhagia, severe anemia, chronic pelvic pain, and rapid enlargement of a myometrial lesion. Transvaginal ultrasound revealed a 9-cm atypical myometrial mass with uncertain echostructure, difficult to classify unequivocally according to the MUSA criteria due to its ambiguous nature of poorly structured solid ('cooked') appearance versus cystic content. MRI findings and radiologist's conclusions were also inconclusive. Concomitant deep infiltrating endometriosis further complicated the interpretation. Because malignancy could not be excluded, the patient underwent surgery. Histopathological examination revealed an apoplectic leiomyoma with extensive infarct-type necrosis and no cytological atypia or mitoticfigures. This case highlights the diagnostic complexity of atypical necrotic leiomyomas and the potential overlap of imaging features between benign degenerative lesions and malignant uterine tumors. In challenging cases, integration of ultrasound findings with MRI, clinical history, and histopathological examination remains essential.