PPL is insufficient to be diagnosed
PPL is insufficient to be diagnosed with radiology alone. The imaging manifestations of pulmonary MALT lymphoma are various and often presented as multiple and bilateral disease. The most frequent findings are consolidations, followed by nodules and masses . Similar results were confirmed in our study. In consolidative forms, bronchial dilatation is a common feature . Unexpected persistence or progression of consolidation lesions during appropriate antibiotic therapy may indicate PPL. Moreover, although pneumonia may produce mediastinal or hilar nodal enlargement, internal mammary nodal enlargement is rare and is highly suggestive of lymphoma . Imaging manifestations of SPL are similar to those of PPL. Nodules, masses, and mass-like consolidation are common and may cavitate, particularly in aggressive lymphoma . Metabolic activity at PET/CT may also be helpful. Pulmonary lymphoma is FDG avid in most cases and FDG is correlated with tumor size [14,16,17]. Secondary pulmonary involvement should be considered in patients with known extrapulmonary lymphoma, particularly in the disseminated disease. Various therapeutic modalities have been applied in clinical practice, such as surgery, chemotherapy, immunotherapy, and Cycloheximide therapy (alone or in combination), but currently no optimal management of pulmonary MALT lymphoma has been defined. Surgery may provide diagnostic purpose and therapeutic resection. Some investigators suggest surgical resection for patients with localized or peripherally located lesions [1,12]. In our study, the majority of enrolled cases presented with extensive disease or symptoms. Under these circumstances, patients received chemotherapy alone at diagnosis, or following partial surgical resection. Response to first-line treatment of primary MALT lymphoma was similar to a previous study reported by the International Extranodal Lymphoma Study Group (IELSG) , with a CRR of 54% and ORR of 78%. R-CHOP is recognized as the standard regimen for DLBCL, resulting in 70%–80% of CR [18,19]. Forty-two cases of primary pulmonary DLBCL with stage IE, age 65 years or younger were reported. All patients were IPI 0–2, of which 91% with IPI 0-1. Upon R-CHOP treatment, 83% of patients achieved CR . To our knowledge, our study represents the first series of Chinese primary pulmonary DLBCL patients in the literature. More than 50% of patients presented with advanced stage (59%) and intermediate-high or high risks of IPI (IPI 3–5, 53%). The CRR and ORR were 76% and 82%, respectively, suggesting primary pulmonary DLBCL may respond well to R-CHOP. However, the response was poor in secondary pulmonary DLBCL, with a CRR and ORR of only 53% and 71%, respectively. Because of the different clinical course of indolent NHL and aggressive NHL, we performed the survival analysis separately. Since pulmonary involvement is selected as a predictive factor in NCCN-IPI , whether NCCN-IPI can still perform well in pulmonary lymphoma is unknown. We found that NCCN-IPI only predicted survival in aggressive PPL. Patients with intermediate-high or high risks of NCCN-IPI experienced significantly worse outcomes than patients with low or low-intermediate risks of NCCN-IPI. This tendency was not presented in aggressive SPL. Our study further explored prognostic factors in aggressive SPL. Age is an important predictive factor in several clinical prognostic indexs, including IPI and NCCN-IPI. Elderly patients often experienced poor prognosis. Recent studies indicated that inflammatory status is essential on lymphoma progression and associated with inferior outcome in lymphoma. The inflammatory-IPI model was first proposed to predict prognosis in DLBCL based on inflammatory factors (LDH, ALC, serum ALB, CRP, β2-MG, and ferritin) . In terms of β2-MG, Nonrepetitive DNA is related to tumor burden in many tumors and has been reported as an adverse prognostic factor in various subtypes of lymphoma [22,23]. β2-MG level was likely to add significant predictive information in aggressive SPL.