Invasive cribriform carcinoma of the breast: mammographic, sonographic, MRI, and 18 F-FDG PET-CT features.

Background: Invasive cribriform carcinoma (ICC) of the breast is a rare type of invasive carcinoma which shows a favorable prognosis and a lower frequency of axillary nodal metastases. Few imaging findings related to ICC have been reported.
Purpose: To evaluate imaging findings with multiple imaging techniques in ICC of the breast.
Material and Methods: Twenty-eight cases of histopathologically proven ICC of the breast were gathered for this study. We retrospectively reviewed the mammographic, sonographic, and magnetic resonance imaging (MRI) findings of ICC according to the American College of Radiology (ACR) breast imaging reporting and data system (BI-RADS) lexicon. 18 F-fluorodeoxyglucose positron emission tomography-computed tomography (18 F-FDG PET-CT) findings were also evaluated. Microscopic slides of surgical specimens were reviewed by a breast pathologist.
Results: The mean age of the patients was 51 years. The most common mammographic findings were irregular shape (72.8%), spiculated margin (63.7%), and a high density (81.8%) mass. Microcalcifications were noted in 9/28 cases. The most common shape was pleomorphic (66.7%). The most common sonographic findings were irregular shape (77.8%), spiculated margin (29.6%), hypoechogenicity (81.5%), and no posterior acoustic features (85.2%). On MRI, most ICCs presented as irregular shaped mass (62.0%) and irregular (42.9%) margin. All four patients (16.0%) who presented with non-mass-like enhancement pattern showed a segmental distribution. The 18 F-FDG PET-CT showed a mean maximum standardized uptake value (SUVmax) of 5.90. Axillary nodal metastases were found in 17.9% (5/28) of the surgical specimens. Immunohistochemical studies showed a high positivity for estrogen and progesterone receptor (100% and 87.5%, respectively).
Conclusion: The imaging features of invasive cribriform carcinoma are highly suggestive of malignancy and are not distinguishable from those of other breast cancers like infiltrating ductal carcinoma.
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