Role of

Background: Primary pulmonary lymphoma (PPL) is a rare form of primary pulmonary malignancy. The clinical significance of Methods: A total of 22 patients with PPL who underwent PET/CT examination before treatment were included in this study. Their clinicopathological parameters and PET/CT parameters were analyzed. Results: Twenty-two patients were retrospectively included, of whom 20 patients presented with respiratory symptoms. The most common imaging finding was consolidation; 40.9% of patients presented with one or more major CT signs divided into the mixed type. A total of 72.7% of the patients had associated CT signs, and air bronchograms were the most common symptom. The imaging findings did not significantly differ between mucosa-associated lymphoid tissue (MALT) lymphoma patients and non-MALT lymphoma patients. Diffuse large B-cell lymphoma (DLBCL) patients had the highest median maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), and total lesion glycolysis (TLG), whereas MALT lymphoma patients presented the highest metabolic tumor volume (MTV). Ten patients underwent posttreatment PET/CT evaluation, which revealed consistent results across the Deauville scale, ∆SUVmax, ∆MTV, and ∆TLG, with more than half of the patients remaining PET positive. After a median follow-up of 48.7 months, 2 patients had died. PPL presents distinct imaging features and metabolic characteristics across pathological subtypes. Although PPL generally has a favorable prognosis, its response to treatment is limited. Conclusions: The various pathological types of PPLs differ in their metabolic characteristics. PPL has a good prognosis but is not sensitive to treatment. PET/CT is integral in the diagnosis, staging, and evaluation of treatment efficacy in PPL and should be considered in clinical decision-making.