Immunoglobulin-G4 related mastitis: A case report.

INTRODUCTION: IgG4-related mastitis (IgG4-RM) is exceedingly rare with only ten cases reported in the literature to date. Organs that are affected with IgG4-related disease (IgG4-RD) all share the same histopathological hallmarks consisting of dense lymphocytic infiltration, storiform fibrosis and obliterative phlebitis. PRESENTATION OF CASE: This case report highlights a case of IgG4-RM found incidentally in a 52-year-old woman during a routine breast screen and it explores the current literature about IgG4-RM and IgG4-RD. DISCUSSION: IgG4-RM and IgG4-RD, in general, is a new entity in the field of medicine and its aetiology is not well understood. In the literature, IgG4-RM often presents as a painless palpable breast lump in isolation or with other systemic manifestations. IgG4-RM is considered benign and has excellent prognosis post-conservative treatment with steroid or surgical excision. CONCLUSION: IgG4-RM is diagnosed exclusively on histological analysis. It is hard to distinguish IgG4-RD from malignant breast lesions purely on clinical examination and imaging studies. Increasing awareness of this condition among clinicians will assist them in managing patients better. Extensive whole body imaging is not recommended unless symptomatic.

Cell cycle marker expression in benign and malignant intraductal papillary lesions of the breast.

AIMS: The diagnosis of intraductal papillary lesions of the breast on core biopsy remains challenging in pathology, with most patients requiring formal surgical excision for a definitive diagnosis. The aim of this study was to determine whether a representative panel of proliferative cell cycle immunohistochemical markers (cyclin A2, cyclin B1 and cyclin D1) could improve the specificity of pathological diagnosis of these lesions. METHODS: A series of 68 surgically excised intraductal papillary lesion cases were retrospectively selected, and immunohistochemistry for cyclin A2, cyclin B1 and cyclin D1 was performed. RESULTS: Cyclin B1 (OR 1.80, 95% CI 1.01 to 3.2, p=0.046) and cyclin D1 (OR 1.13, 95% CI 1.05 to 1.22, p=0.002) expression was independently associated with a diagnosis of malignancy in papillary lesions, although expression was frequently heterogeneous and only focal. Cyclin A2 expression (OR 0.76, 95% CI 0.41 to 1.4, p=0.38) was not associated with a malignant diagnosis in multivariable logistic regression models. All three cyclins displayed high sensitivity (80%-95%) for a diagnosis of malignancy, although cyclin B1 showed a superior specificity of 72.7% compared with the low specificity of cyclins A2 and D1. CONCLUSIONS: Our study has identified for the first time that the expression of key cell cycle markers differs between benign and malignant papillary breast lesions and identified changes to the mitotic marker, cyclin B1, as particularly significant. However, given the low level and heterogeneous nature of expression of these markers, there remains a significant risk of undersampling in core biopsies and thus they are unlikely to be useful in routine clinical practice.