Pulmonary lymphoid neoplasms. Role of immunohistology in the study of cellular immunotypes and in differential diagnosis.

Seven cases of lymphoid neoplasms presenting in the lung were evaluated by immunohistology for T and B cell antigens and immunoglobulin light chains in frozen tissue sections. Although follow-up was short or inconclusive in some patients with lymphoma and pseudolymphoma, it was concluded that evaluation of T and B cell antigens and immunoglobulin light chains in frozen tissue is helpful in classifying lymphocytic neoplasms, especially in cases without definite cytologic evidence of malignancy. As demonstrated in two additional cases, lymphocyte/leukocyte markers in paraffin-embedded tissue are important in the differential diagnosis of lesions with cytologic features of malignancy.