Granulomatosis with polyangiitis with breast involvement mimicking metastatic cancer: Case report and literature review

Abstract

Granulomatosis with polyangiitis (GPA) is a systemic inflammatory disease, characterized by the presence of necrotizing vasculitis of small and medium-sized vessels, granulomatous inflammation and anti-neutrophil cytoplasmic antibodies (ANCAs). The diagnosis can be challenging due to the variable clinical presentation and possible involvement of virtually all organ systems. A correct diagnosis is indispensable for a timely start of medical treatment and to avoid unnecessary surgery. Therefore, cooperation with and the input of the pathologist is crucial. We report a case of a woman presenting with suspected metastatic cancer. The diagnosis of GPA was made mainly based on breast biopsy, and the patient was treated accordingly, with full recovery. This report provides a case description and a brief review of the literature.

Figure 1. a–c

Transaxial fused PET-CT (a), CT (b), and PET (c) images show a strongly hypermetabolic nodular lesion in the right breast.

Figure 2. a, b

Core needle biopsy of the breast. The H&E stained section (50× magnification) shows (a) mammary parenchyma diffusely infiltrated by a dense, mixed inflammatory infiltrate involving the adipose tissue and sparing the ducts, and the presence of some multinucleated giant cells (Touton cells), localized mostly at the periphery of the inflammatory infiltrate and (b) extensive zones of infarct and necrosis of the breast parenchyma.

Figure 3. a, b

Core needle biopsy of the breast. The H&E stained section (400× magnification) shows (a) involvement of a small artery in a zone of fat necrosis, with thickening of the vessel wall, infiltration by inflammatory cells and focal fibrinoid necrosis, and (b) two small veins showing thickening of the vessel wall and infiltration by a mixed inflammatory infiltrate.

Figure 4

Kidney core needle biopsy. Jones’ staining (methenamine silver-Periodic acid- Schiff stain; 200× magnification) shows a crescent formation within the glomerulus.