Well-differentiated lymphocytic lymphoma. A study of 47 patients with primary manifestation in the lung.

Forty-seven cases of primary well-differentiated lymphocytic lymphoma (WDL) of the lung were studied. Diagnosis was based on histologic identification of a lymphangitic pattern of infiltration and monomorphous (homogenous) cytologic composition. Nineteen cases (40%) had ancillary evidence supportive of a diagnosis of lymphoma including simultaneous or subsequent involvement of other organs, monoclonal immunologic markers, or a monoclonal serum gammopathy. The prognosis for the group as a whole was excellent; follow-up (median, 4 years) was available for 33 cases. Only one patient has died of lymphoma. The authors discuss the histologic differential diagnosis of lymphocytic infiltrates in the lung, propose criteria to distinguish reactive from neoplastic lymphocytic lesions, and discuss the significance of monoclonality in the management of these patients.