To analyze the mammographic, MRI, and clinicopathological characteristics of primary breast lymphoma (PBL).

Clinicopathological characteristics were retrospectively reviewed and analyzed in 32 patients with histopathologically proven PBL. All cases were female (mean age, 50 years; median age 46 years; range, 30-68 years).

In the 32 cases, there were bilateral tumors in 5 cases and 27 cases of unilateral involvement. The patients presented with a painless mass in 25 cases and with pain in 7 cases. Rapid enlargement was observed in 6 cases. Mammograms of 17 tumors showed a round, circumscribed mass with high density or iso-density in 9, asymmetry in 7 and no abnormality was found in one. 37 lesions were detected on dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) in 29 patients, among which 25 (67.6%) lesions appeared as enhancing masses and 12 (32.4%) lesions as non-mass enhancements. All lesions showed iso- or hypo-intense signal on the T1WI and hyper-intense signal on the T2W1. Analysis of the enhancing masses based on the 2013 ACR BI-RADS lexicon revealed that among the mass descriptors in 25 lesions, the most common features were circumscribed or irregular margin in 24 (96.0%) and homogeneous internal pattern in 19 (76.0%). Of the 12 non-mass enhancing lesions, the most common descriptors included regional or multiple regional distribution in 6 (50.0%), and heterogeneous internal pattern in 8 (66.7%). The tumors showed early enhancement with penetrating vessels on DCE-MRI in 16 lesions, associated with skin thickening in 14, and axillary lymphadenopathy in 19. The time-signal intensity curve (TIC) in 14 patients was mainly of type Ⅲ (7/14, 50.0%).

Some imaging features may alert the diagnosis of primary breast lymphoma, but final diagnosis depends on histopathology. Early diagnosis is helpful for selecting appropriate treatment regimens.

Lymphoma; Breast neoplasms; Neoplasms, multiple primary; Radiography; Magnetic resonance imaging