Imaging Spectrum of Typical and Atypical Adenomyosis.

Adenomyosis, characterized by heterotopic endometrial tissue within the myometrium, is a common yet poorly understood condition affecting patients of childbearing age. Although typical features of adenomyosis are extensively discussed in the literature, there is no consensus on its imaging classification. The Morphological Uterus Sonographic Assessment (MUSA) consensus statement is a valuable tool for identifying and describing typical adenomyosis imaging features at US. However, for MRI, there is still no standardized consensus for descriptors and subtypes. The diverse atypical manifestations of adenomyosis are a diagnostic challenge. Familiarity with these manifestations is essential for accurate diagnosis, avoiding misdiagnosis, and ensuring optimal clinical management. The authors examine the imaging appearances of typical and atypical adenomyosis at US and MRI, encompassing focal adenomyosis, diffuse adenomyosis, adenomyomas (solid and cystic types), polypoid adenomyomas, adenomyosis during pregnancy, and malignant transformation. The discussion includes clinical, surgical, and pathologic aspects in the differential diagnosis, with consideration of uterine contractions, deep endometriosis with myometrial infiltration, leiomyomas, and accessory cavitated uterine masses. Practical tips are provided to assist radiologists in distinguishing adenomyosis from other conditions. ©RSNA, 2025 Supplemental material is available for this article.