Secondary pulmonary lymphoma diagnosed by minimal residual disease detected in bronchoalveolar lavage fluid: A case report.

The present study reports 2 cases of non-Hodgkin's lymphoma (NHL) that achieved complete remission following cyclophosphamide, hydroxydaunorubicin (doxorubicin), oncovin (vincristine) and prednisone chemotherapy. Both patients subsequently developed respiratory distress and rapid progression. The initial diagnosis was pulmonary infection, based on the symptoms of cough, white sputum and fever, abnormal laboratory results of high white blood cells, C-reactive protein and procalcitonin and most notably, chest CT scans showing ground-glass opacities and patchy shadows. Following treatment with a number of antibiotics, the pulmonary symptoms of the patients and their imaging manifestations improved at first. The repeated negative results of sputum culture and next-generation sequencing of bronchoalveolar lavage fluid (BALF) confirmed that the pathogens were eliminated. However, later, the symptoms and signs of both patients continued to progress. Secondary pulmonary lymphoma was not confirmed until the discovery of lymphocytes with abnormal phenotypes following minimal residual disease (MRD) testing in BALF. Both patients ultimately succumbed to respiratory failure. The present report outlines the first 2 reported cases of NHL diagnosed through MRD detection in BALF alongside a review of the relevant literature.