Pyothorax-associated lymphoma is known to develop in patients who received an artificial pneumothorax for pulmonary tuberculosis some 30 to 40 years previously. Such patients exhibit large, immunoblastic lymphoma cells and often have a B-cell phenotype. We present a patient with an artificial pneumothorax and such a late developing lymphoma but with the unique finding of aberrant T- and B-cell phenotypes. Southern blot hybridization using immunoglobulin gene JH and T-cell receptor beta chain receptors revealed germline configurations. Lymphomas developing in immunocompromised patients, such as those with acquired immunodeficiency syndrome, may show such unusual phenotypes. The unusual phenotypes found in this patient provide evidence that his pyothorax-associated lymphoma was related to an immunocompromised state.