A case of lymphocytic mastopathy requiring differential diagnosis from primary breast lymphoma

Mastitis in Autoimmune Diseases: Review of the Literature, Diagnostic Pathway, and Pathophysiological Key Players

Mastitis frequently affects women of childbearing age. Of all the pathological breast conditions requiring specific management, autoimmune mastitis is in the third position after infection and breast cancer. The aim of this literature review was to make a comprehensive description of autoimmune diseases targeting the mammary gland. Four main histological patterns of autoimmune mastitis are described: (i) lymphocytic infiltrates; (ii) ductal ectasia; (iii) granulomatous mastitis; and (iv) vasculitis. Our literature search found that all types of autoimmune disease may target the mammary gland: organ-specific diseases (diabetes, thyroiditis); connective tissue diseases (such as systemic erythematosus lupus or Sjögren’s syndrome); vasculitides (granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis, giant cell arteritis, polyarteritis nodosa, Behçet’s disease); granulomatous diseases (sarcoidosis, Crohn’s disease); and IgG4-related disease. Cases of breast-specific autoimmune diseases have also been reported, including idiopathic granulomatous mastitis. These breast-limited inflammatory diseases are sometimes the first symptom of a systemic autoimmune disease. Although autoimmune mastitis is rare, it is probably underdiagnosed or misdiagnosed. Early diagnosis may allow us to detect systemic diseases at an earlier stage, which could help to initiate a prompt, appropriate therapeutic strategy. In case of suspected autoimmune mastitis, we hereby propose a diagnostic pathway and discuss the potential pathophysiological pathways leading to autoimmune breast damage.

Two cases of diabetic mastopathy: MR imaging and pathological correlation

Diabetic mastopathy is a rare benign condition associated with long-standing diabetes mellitus and presents with breast lumps. This report describes two cases in which diffusion-weighted images (DWI) on magnetic resonance imaging were quite different from each other. In case 1, there were hyperintense lesions on DWI, and surgically removed specimens revealed ductitis with marked lymphocytic infiltration. In case 2, no abnormal intensity was depicted on DWI, and biopsy specimens showed dense stromal fibrosis with mild perivascular lymphocytic infiltration that corresponded to previous reports. Although it is reported that diabetic mastopathy is composed of dense fibrous tissue with low cellularity that results in no hyperintense lesion on DWI, in cases with marked lymphocytic infiltration, strong hyperintensity can be seen on DWI mimicking malignant breast tumors.

The clinical significance of recognizing distinct morphologic features of systemic diseases on breast biopsies

Prominent lymphocytic periductal inflammation has been previously described in association with diabetes mellitus type I and II, other autoimmune diseases such as lupus, thyroid disease, and connective tissue abnormalities, and even lymphomas. When incidentally detected in a breast biopsy and without evidence of systemic disease in the patient's history, it may be prudent to alert the treating clinician to the possibility of an underlying systemic disease process, in order to ensure recognition and appropriate clinical follow-up for these patients. The purpose of this review is to familiarize the reader with this commonly encountered incidental feature on breast biopsies and to emphasize the importance and clinical implications of recognizing possible underlying systemic disease and communicating these findings to the treating physicians.

FDG PET/CT manifestations of hematopoietic malignancies of the breast

Hematopoietic malignancies that can be encountered in the breast include lymphoma, leukemia, and multiple myeloma/plasmacytoma. These are readily imaged via [18]F-fluorodeoxyglucose position emission tomography (PET)/computed tomography (CT) and can manifest as unilateral, bilateral, single, multiple, round/oval masses, or diffuse. These malignancies can occasionally mimic primary breast cancers. Conversely, benign conditions, such as the lactating breast can resemble hematopoietic malignancies of the breast. Although uncommon, familiarity with hematopoietic malignancies of the breast is important for proper interpretation of PET/CT. In this pictorial review, the PET/CT imaging features of patients with hematopoietic malignancies of the breast will be described, including pathology-proven cases of acute myelogenous leukemia, diffuse B-cell lymphoma, follicular lymphoma, acute myeloid leukemia with neutropenic granulocytic) sarcoma, and plasmacytoma. In addition, potential pitfalls will be discussed.