Primary lymphoproliferative conditions of lung.

The clinical, laboratory, and pathological features of six primary lymphoproliferative conditions of the lung are described. These comprise two patients with malignant lymphomas, one with pseudolymphoma, one with lymphoid interstitial pneumonia (LIP), one with lymphomatoid granulomatosis, and one with plasma cell granuloma. We recommend that the term 'premalignant lymphoma' be used for pseudolymphoma since the condition, although tending to remain localised, has a malignant potential. A combination of dyspnoea, cough, and pyrexia were the presenting features in our cases of premalignant and malignant lymphoma although they may often be discovered accidentally by chest radiography. The patient with LIP presented with the usual symptoms of dyspnoea and cough. The initial manifestations of the patient with lymphomatoid granulomatosis were skin radh and peripheral neuropathy nine months before the pulmonary symptoms, a not unusual occurrence. Plasma cell granuloma is often asymptomatic but our patient presented with cough, chest pain, haemoptysis. Premalignant lymphoma tends to pursue a benign course although exceptionally it may become disseminated. Malignant lymphoma may remain localised for many years but a significant proportion metastasise. Lymphomatoid granulomatosis and LIP have a varied course but both may terminate in malignant lymphoma. Plasma cell granuloma is always benign. The interrelationships of these conditions and their differential diagnosis are discussed.