Radiological and clinical features of adult non-puerperal mastitis

Abstract

Objective: To describe the radiological and clinical features of adult non-puerperal mastitis and to determine the most accurate method of preventing unnecessary surgical procedures.

Methods: Clinical and imaging findings were retrospectively reviewed in 51 females with non-puerperal mastitis, which was confirmed by biopsy/surgical pathology. All 51 patients had pre-operative MRI; 45 patients also had sonograms and 25 also had mammograms, pre-operatively.

Results: Of the 51 cases with non-puerperal mastitis, 94.1% (48/51) were confirmed as having acute or chronic inflammation, and the other 3 had plasma cell mastitis; areola papillaris inflammation was found in 39.2% (20/51) of the cases. Overall, 6 of the 25 cases that were examined with mammography and 2 of the 45 cases that were examined with sonography appeared normal, but all 51 lesions were positively identified on MRI. Asymmetrical density (12/25) on mammograms and solitary or separated/contiguous, clustered, hypoechoic mass-like lesions (31/45) on ultrasound were the most common signs of non-puerperal mastitis. On enhanced MRI, 90.2% (46/51) of patients showed non-mass-like enhanced lesions. Multiple regional enhancements in the pattern of distribution (32/46) and separated or contiguous, clustered, rim-like enhancements in the pattern of internal enhancement (29/46) were the most common manifestations in non-mass-like enhanced lesions. Of the 51 patients, mastitis Type 1 and Type 2 in the time-signal intensity curve were detected in 47.1% and 51.0% of the patients, respectively. The breast imaging reporting and data system categories with the highest number of patients were Category 0 (9/25) on mammography, Category 4a on sonography (18/45) and Category 4a on MRI (29/51).

Conclusion: The findings from mammography and ultrasound are non-specific; therefore, using MR can be helpful in the diagnosis, especially in the presence of non-mass-like enhancements that are multiple, regional, separated, or contiguous, clustered and rim-like.

Advances in knowledge: Mastitis is often neglected because of the lack of typical clinical signs and symptoms. This study has assessed and described the clinical features and imaging findings of adult non-puerperal mastitis on mammograms, sonograms and MRI and found that MRI is more specific in the diagnosis of disease.

Figure 1.

Female, 43 years old, chronic mastitis. Mammography showed a focal asymmetrical density in the right breast (arrows).

Figure 2.

Female, 34 years old, chronic mastitis. Mammography demonstrated an ill-defined, high-density mass in the left breast (arrows).

Figure 3.

Female, 40 years old, acute/chronic mastitis. Sonogram showed a hypoechoic, mass-like lesion in the left breast, and the lesion was clustered but separate.

Figure 4.

Female, 43 years old, chronic mastitis. Sonogram revealed a hypoechoic, mass-like lesion in the right breast, and the lesion showed a contiguous, clustered appearance.

Figure 5.

Female, 39 years old, chronic mastitis. Enhanced MR images showed multiple, separated, clustered, rim-like enhancements in the right breast.

Figure 6.

Female, 47 years old, acute/chronic mastitis. Enhanced MR image showed multiple, contiguous, clustered, rim-like enhancements in the left breast (a); Type 1 time–signal intensity curves were obtained (b, c) and the sagittal MR image showed a non-mass-like enhanced lesion directed to the nipple along the breast ducts (d).

Figure 7.

Female, 24 years old, acute mastitis. Enhanced MR images showed patchy enhancements.

Figure 8.

Female, 39 years old, chronic mastitis. A gross blood vessel was found behind the heterogeneous enhanced lesion on enhanced MRI (arrow).

Figure 9.

Female, 66 years old, chronic mastitis. MR images showed a subareolar, irregular shaped, homogeneous, enhanced mass in the right breast.

Figure 10.

Female, 54 years old, chronic mastitis. Enhanced MR images showed that the chest wall was involved in the inflammatory lesion.

Figure 11.

Female, 42 years old, acute/chronic mastitis. Mammogram showed diffuse asymmetrical density but with a Type IV mammary gland (≥75% dense tissue) (a); mammary sonogram revealed a multiple, contiguous, tubular hypoechoic lesion (b); enhanced MR images showed multiple, separated, clustered, rim-like enhancements in the left breast (c, d).