Background: Granulomatous angiopanniculitis (GAP) is a rare benign condition of the breast of unknown etiology. Clinically and by fine needle examination, GAP may simulate breast carcinoma. The cytologic characteristics have not been described before.
Case: A 63-year-old female exhibited a palpable mass in her left breast. The fine needle aspirate contained both epithelioid and stromal elements. The epithelioid component consisted of dissociated individual cells and small groups and clusters of atypical cells. The stromal component showed a uniform, not-atypical pattern. The lumpectomy specimen showed nonnecrotizing granulomatous panniculitis and lymphoid angiitis without involvement of ducts or lobules.
Conclusion: Granulomatous lesions should be borne in mind in the differential diagnosis of breast cancer in fine needle aspiration cytology. GAP must be histopathologically distinguished from granulomatous inflammation in the breast of autoimmune or infectious origin as specific medical therapy may be available for these latter diseases.