Pulmonary lymphomas and other pulmonary lymphoid lesions. A clinicopathologic and immunologic study of 64 patients.

Sixty-four patients with lymphoid lesions involving the lung were separated into three groups. In 32 patients, the predominant lymphoid cell population consisted of small, mature-appearing round lymphocytes with or without plasmacytoid features. This group, designated small lymphocytic proliferation (SLP), represents a heterogeneous group of pulmonary lymphocytic lesions including small lymphocytic lymphoma, lymphocytic interstitial pneumonia, and lymphoid hyperplasia (pseudolymphoma). Thirteen SLP patients were identified as having small lymphocytic lymphoma on the basis of monoclonality, progressive disease in other sites, or both. This group was morphologically identical to the remainder of the SLP patients, except for a higher incidence of plasmacytoid features (P = 0.003) and a greater degree of mast cell infiltration (P less than 0.05). Four of these 13 patients subsequently developed an aggressive large cell lymphoma resulting in death in three patients. The median survival for all of the SLP patients has not yet been reached. Patients in whom a monoclonal cell population could be established showed a slightly worse prognosis of borderline statistical significance (P = 0.09); however, the presence of a serum monoclonal gammopathy conveyed a significantly worse prognosis (P = 0.003). The remaining two groups of patients had various forms of malignant lymphoma other than the small lymphocytic type. One group of 12 patients, designated as having presumed primary lymphoma limited to one or both lungs (PL), had a prolonged course with a median survival of 117 months. The remaining 20 patients had disseminated lymphoma also involving lung (DL); DL patients had a shorter median survival of 33 months.