Misdiagnosis of Primary Mucosa-Associated Lymphoid Tissue Lymphoma of the Pleura: Case Report and Literature Review.

Background:Mucosa-associated lymphoid tissue (MALT) lymphoma is an indolent B cell lymphoma. Its occurrence in the pleura is rare, with atypical clinical manifestations. MALT of the pleura is easily misdiagnosed. This is the first case report of pleural MALT lymphoma in China.Case Description:We report the case of a 54-year-old Chinese man with no notable medical history who complained of cough, sputum, and shortness of breath for 3 months. He had a positive purified protein derivative (PPD) test. An initial misdiagnosis of pleural tuberculosis was corrected, after 3 thoracoscopic biopsies and tests, to primary pleural MALT lymphoma. He received treatments of R-CHOP (rituximab, cyclophosphamide, epirubicin, vindesine and prednisolone) and traditional Chinese medicine. The patient was followed for 3 years until June 2022, with no obvious respiratory symptoms. Pleural MALT lymphoma is extremely rare, with only a few cases reported. This article describes our case, and includes an overview of 15 previously reported cases to summarize the characteristics, treatments, and prognosis of primary pleural MALT lymphoma.Conclusions:Pleural MALT lymphoma is rare, and a correct diagnosis depends on tissue biopsy, immunohistochemical staining, and detection of gene rearrangement. Thoracoscopy is important to diagnose this disease. Multiple thoracoscopic biopsies may be necessary.