Case discussion
01Clinical context
MRI was performed for a patient with multiple bilateral breast cysts, some showing complicated features and indeterminate cytology from right breast fine needle aspiration (FNA).
02Key imaging findings
Multiple bilateral simple and complicated breast cysts are present, more numerous on the left. Several cysts show smooth, uniformly enhancing walls up to 3.5 mm thick on the right and 2.5 mm on the left, consistent with benign reactive or inflammatory changes, possibly related to duct ectasia. No definite irregular enhancing mural nodules or intracystic solid components are seen. Dynamic kinetic analysis shows negligible enhancement within cystic regions, supporting benign cystic nature. Mildly prominent right axillary lymph node with cortical thickening up to 4.5 mm but preserved fatty hilum is noted. An incidental 6 mm probable benign hepatic cyst is also seen. MRI shows no definite enhancing solid breast malignancy, but the indeterminate right breast FNA cytology raises concern for possible underlying neoplasm that MRI alone cannot exclude.
03Diagnostic reasoning
The diagnosis was based on MRI sequences demonstrating multiple bilateral breast cysts with variable proteinaceous or hemorrhagic content. The smooth, uniformly enhancing cyst walls without irregular mural nodules or intracystic solid components suggested benign reactive or inflammatory changes, likely related to duct ectasia. Dynamic contrast-enhanced kinetic analysis showed negligible enhancement within cysts, supporting their benign nature. The presence of an indeterminate right breast FNA cytology raised concern for occult neoplasm, which MRI could not exclude. Additional ultrasound correlation and histopathological assessment were recommended to clarify the diagnosis.
04Questions for clinical practice
What is the significance of the smooth wall enhancement in breast cysts? Smooth, uniform wall enhancement typically indicates benign reactive or inflammatory changes rather than malignancy. How should indeterminate FNA cytology be managed? Indeterminate cytology requires histopathological confirmation, often via core needle biopsy or surgical excision, to exclude neoplasm. When should targeted ultrasound be performed? Targeted ultrasound is recommended to correlate MRI findings with specific cysts, especially those with prominent wall enhancement or indeterminate cytology, to guide biopsy or further management. Does MRI exclude malignancy in complicated cysts? MRI cannot definitively exclude an underlying neoplasm in complicated cysts with indeterminate cytology; tissue diagnosis remains essential.
05Teaching point
MRI can characterize multiple simple and complicated breast cysts and identify features suggestive of benign reactive changes such as smooth wall enhancement and lack of suspicious solid components. However, MRI cannot definitively exclude an underlying cyst-associated neoplasm when cytology is indeterminate. Histopathological correlation remains essential, especially when fine needle aspiration results are inconclusive. Imaging findings should guide but not delay tissue diagnosis and surgical consultation.
Shown for education. De-identified — no identifiable patient data. A radiology report is a specialist opinion and must be read with the full clinical context by the treating physician.
