Granulomatous angiopanniculitis of the breast

The clinical and pathologic features of six examples of nonnecrotizing granulomatous angiopanniculitis (GAP) of the breast are reported. The patients presented with a solitary ill-defined breast mass causing clinical suspicion of carcinoma. Histopathologically, all lesions consisted of multiple nonnecrotic, noncaseous granulomas with a giant cell component predominantly involving the subcutaneous adipose tissue, extending into the underlying mammary tissue without affecting lobules or ducts. A nonleukocytoclastic lymphocytic angiitis involved small vessels and capillaries. None of the patients had a history of an autoimmune disorder or had previous diagnoses of erythema nodosum or multiforme, leukocytoclastic or nonleukocytoclastic vasculitis, or Weber-Christian disease. Treatment was limited to biopsy in all six patients. Studies for infectious agents on specimens were negative. Five of the six patients developed one or more recurrences in the breast or elsewhere on the body. Four patients experienced spontaneous regression of their recurrent lesions. GAP appears to be a self-limited disorder of uncertain etiology which involves the breast and other sites. It may represent a variant of Weber-Christian disease, as the two diseases share similar clinical and histologic features. GAP must be distinguished from causes of granulomatous inflammation of the breast for which specific medical therapy is available.