A 39-year-old male presented with gradually increasing breast lumps on both sides for 1.5 years with no history of trauma. There was no past history of diabetes, hypertension, tuberculosis, pancreatitis, joint pains, fever or weight loss. On palpation, slightly tender subcutaneous masses measuring approximately 3 x 3  and 2 x 2 cm were noted in the left supra-areolar region and the right upper outer quadrant, respectively.
Ultrasonography in the regions of the palpable abnormality (Figure 1) revealed an ill-defined, hyperechoic, subcutaneous mass with internal vascularity measuring 25 x 7 mm in the left supra-areolar region and another mass measuring 22 x 9 mm in the upper outer quadrant of the right breast [breast imaging-reporting and data system (BI-RADS) 4a]. Multiple subcentimetre lymph nodes with a few showing an attenuated hilum were seen in both the axillae (more on the left side) and the cervical regions.
On mammography (Figure 2), an ill-defined, dense (compared with subcutaneous fat) mass was noted in the upper half of the left breast and upper outer quadrant of the right breast, with no evidence of calcification, architectural distortion or skin retraction (BI-RADS 4a).
Contrast-enhanced dynamic MRI of the breasts (Figures 3 and 4) showed focal areas of marked fat stranding with overlying skin thickening measuring 29 x 24 and 13 x 8 mm superolateral to the left nipple and the right upper outer quadrant, respectively. These areas were markedly hyperintense on T 2 weighted fat-suppressed sequence. On contrast administration, the lesions showed heterogeneous enhancement and predominantly Type I kinetic enhancement curves. No evidence of restricted diffusion was noted bilaterally. Both the lesions had similar morphological and kinetic features. The lesions were characterized as BI-RADS 4.
Since the imaging findings were inconclusive, histopathological evaluation was advised. Ultrasonography-guided core needle biopsy was performed on the larger lesion in the left breast. Histopathology (Figure 5) revealed fibrofatty tissue fragments infiltrated by lymphoplasmacytic cells arranged in a lobular and focally septal distribution. Few of the vessels showed sclerosis, intimal oedema and lymphocytic infiltration. Focally, the infiltrate revealed a few scattered, intermediate-sized, transformed lymphocytes/immunoblasts. There was no evidence of granulomatous or neoplastic pathology. On immunohistochemistry (CD2, CD5 and CD7), no loss of T-cell antigen was seen. Histopathological findings were suggestive of panniculitis, likely autoimmune related.
Quantitative serum antinuclear antibody (ANA) analysis (IgG immunodot assay) was carried out and SS-A/Ro 60-kD, sp100, M2 recombinant and M2 native turned positive with values of 100, 33, 28 and 37 U ml-1, respectively. The ANA HEp-2 was positive at 1 :  40 titre and showed a fine speckled pattern. Anti-dsDNA antibody was negative. The leukocyte count, erythrocyte sedimentation rate, renal and hepatic function tests, urine analysis and serum amylase and lipase were within normal limits.
Lupus mastitis or lupus panniculitis of male breast is a very uncommon condition that is a clinical and radiological mimicker of malignancy and in the absence of history of autoimmune disorder can lead to mismanagement of the disease as breast malignancy. The close clinical and radiological similarity of this condition with panniculitis-like T-cell lymphoma also adds to the diagnostic dilemma. However, histopathology, immunohistochemistry and serum markers for autoimmune disorders help in diagnosis.
Lupus mastitis is an unusual, benign disease that is very uncommon in males.
Imaging and clinical findings are non-specific as it mimics mastitis and malignancy.
Timely diagnosis with histopathological and serum analysis is the key to management.
Written informed consent for the case to be published (including images, case history and data) was obtained from the patient for publication of this case report, including accompanying images and is within the hospital records.