Pseudolymphoma of the breast. I. In a study of 8,654 consecutive tylectomies and mastectomies

Pseudolymphoma is a benign pathological process that morphologically resembles malignant lymphoma. Its occurrence in the mammary tissue has been described but has not been well investigated. We conducted a prospective and retrospective study of 8,654 consecutive mastectomies and tylectomies of the breast and found only 9 cases (0.1%) of primary lymphoreticular lesions. Of these 9, 5 were pseudolymphomas; 3, histiocytic lymphomas; and 1, Hodgkin's disease. Clinically, pseudolymphoma of the breast was described as an enlarging mass giving a dull, aching sensation. A history of physical trauma to the affected area could be traced in 3 patients with certainty. The mean patient age of the entire series was 36 years. Grossly, the tumor was a solid, firm nodule without any evidence of fibrocystic disease. Microscopically, it showed a lymphoid infiltrate with a nodular pattern. Three of the 5 cases revealed distinct germinal centers. Atypical lymphoid cells were not observed in any of these cases. After local excision, no patients had recurrence over a period of two to eight years. In view of a history of trauma, accompany fat necrosis in some cases, IgG gammopathy, it is postulated that pseudolymphoma of the breast, probably akin to pseudolymphoma of the lung, may represent an overwhelming local response to an injury. This lesion, reactive in nature, should be differentiated from a malignant lymphoma so that patients are not subjected to unnecessary mastectomy, radiation, or chemotherapy.