An inconspicuous pulmonary diffuse large B-cell lymphoma

Abstract

Abstract Background pulmonary primary diffuse large B-cell lymphoma is an extremely rare B cell lymphoproliferative disorder, and cases mimicking an unspecific pulmonary inflammatory lesion are even rarer, which can be easily misdiagnosed.Case presentation: We reported a 33-year-old female patient with multiple ground glass nodules in the lung on chest computed tomography (CT) and Positron emission tomography-computed tomography (PET-CT) scans. Pulmonary biopsy revealed tumor cells growing along the alveolar septum, hiding in an inflammatory background. Although some tumor cells invaded blood vessels, the majority of the tumor cells were distributed outside the vessels. Based on the morphology, immunohistochemistry, and molecular detection, the diagnosis was confirmed as pulmonary primary diffuse large B-cell lymphoma, anaplastic variant. The diagnosis of this type of tumor is challenging due to its clinical and pathological characteristics, requiring differentiation from inflammatory lesions and intravascular large B-cell lymphoma. Tumor cells expressed CD30 and CD20. The patient was treated with brentuximab vedotin (BV) combined with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone(R-CHOP) regimen for six courses, resulting in almost complete disappearance of the lesions. The patient had a good prognosis, with no involvement of other sites after a six-month follow-up.Conclusions This case emphasizes the rarity of pulmonary primary diffuse large B-cell lymphoma and the significance of being attentive to atypical imaging and pathological morphology that may lead to misdiagnosis. Treatment with BV combined with R-CHOP therapy resulted in complete remission of the lesions. Hence, clinicians and pathologists should carefully observe and consider this diagnosis in such cases.