Radiologic and clinical features of idiopathic granulomatous lobular mastitis mimicking advanced breast cancer

Abstract

Idiopathic granulomatous lobular mastitis (IGLM), also known as idiopathic granulomatous mastitis, is a rare chronic inflammatory lesion of the breast that can clinically and radiographically mimic breast carcinoma. The aim of this study was to describe the radiological imaging and clinical features of IGLM in order to better differentiate this disorder from breast cancer. We performed a retrospective analysis of the clinical and radiographic features of 11 women with a total of 12 IGLM lesions. The ages of these women ranged between 29 and 42 years, with a mean age of 34.8 years. Ten patients were examined by both mammography and sonography and one by sonography alone. The sites that were the most frequently involved were the peripheral (6/12), diffuse, (3/12), and subareolar (3/12) regions of the breast. The patient mammograms showed irregular ill-defined masses (7/11), diffuse increased densities (3/11), and one oval obscured mass. In addition, patient sonograms showed irregular tubular lesions (7/12) or lobulated masses with minimal parenchymal distortion (2/12), parenchymal distortion without definite mass lesions (2/12), and one oval mass. Subcutaneous fat obliteration (12/12) and skin thickening (11/12) were also observed in these patients. Contrary to previous reports, skin changes and subareolar involvement were not rare occurrences in IGLM. In conclusion, the sonographic features of IGLM show irregular or tubular hypoechoic masses with minimal parenchymal distortion. Both clinical information and the description of radiographic features of IGLM may aid in the differentiation between IGLM and breast cancer, however histological confirmation is still required for the proper diagnosis and treatment of the disorder.

Fig. 1

Mammogram and ultrasound of a 34-year-old woman 2 months after mass detection. A. The MLO mammogram shows an irregular, indistinct high density mass in the upper left breast. B. The ultrasonography shows an ill-defined, irregular tubular, heterogeneous hypoechoic lesion.

Fig. 2

The mammogram and ultrasound of a 33-year-old woman in 2 months after the detection of a palpable mass in the left breast. A. The mammogram shows a diffuse, increased density in the left breast, but without calcification. B. The ultrasound shows parenchymal distortion without a definite mass lesion. CT scan of a 33-year-old woman in 2 months after the detection of a palpable mass in the left breast. C. The axial CT scan shows heterogeneous enhancing mass lesion with prominent skin thickening.

Fig. 3

The ultrasound and mammogram of a 34 year-old woman 2 months after the detection of a mass in the right breast. A. Ultrasonography shows a well-defined, oval, heterogeneous hypoechoic mass. B. The MR mammogram shows an abscess-like lesion with a rim enhancement in the right breast.