Computed Tomographic Manifestations of Pulmonary non-Hodgkin’s Lymphoma

The purpose of this study is to describe computed tomography (CT) findings of pulmonary non-Hodgkin’s lymphoma. Thirty-seven patients (24 to 92-years-old, mean 67, 27 males) with pulmonary non-Hodgkin’s lymphoma confirmed by pathology and encountered over a period of more than 10 years were reviewed. Pulmonary specimens were obtained by CT-guided core biopsy (n =16), transbronchial biopsy (n =15) and surgery (n =6). The pathological diagnoses were mucosa-associated lymphoid tissue (MALT) lymphoma (n=19), diffuse large B cell lymphoma (DLBCL) (n=13), anaplastic cell lymphoma (n=2), mantle cell lymphoma (n=2), and Burkitt’s lymphoma (n=1). The chest CT findings included consolidation (86.5 %), ground glass opacity (GGO) (78.4%), air-bronchograms (70.3%), lymphadenopathy (70.3%, of which 80.8% had hilar involvement), CT-halo sign (67.6%), lung nodule (54.1%), reticular opacities (48.6%) and pleural effusion (24.3%). Of 37 cases, 30 (81.1%) had concurrence of more than 3 findings and 26 patients (70.3%) had more than 4 findings. Mediastinal lymphadenopathy was found significantly more often in cases of non-MALT rather than MALT lymphoma (p = 0.03) and more often in cases of secondary or recurrent lymphoma compared to primary NHL (p < 0.05). It is concluded that the concurrence of more than 3 findings on chest CT images should alert one to consider the possibility of lymphoma. Correspondence Author to: Yung-Liang Wan Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital at Linkou, Healthy Aging Research Center, College of Medicine, Chang Gung University, Taoyuan, Taiwan No. 5, Fu-Xing Road, Gui-Shan, Taoyuan 333, Taiwan J Radiol Sci 2013; 38: 77-83 CT of pulmonary non-Hodgkin’s lymphoma 78 J Radiol Sci September 2013 Vol.38 No.3 MATERIALS AND METHODS Patients and Methods The institutional review board approved this retrospective study. Informed consent was obtained from all patients who underwent CT. Over a period of 10 years and 10 months from May 1999 to February 2010, 41 of 2535 cases of proven lymphoma were pulmonary lymphoma. Four of the 41 cases were excluded due to incomplete medical records or suboptimal imaging studies. The remaining 37 patients formed the basis of this study. The specimens of lung lesion for histopathology and immunohistochemistry to diagnose lymphoma subtypes were obtained by CT-guided core needle biopsy (n = 16), transbronchial biopsy (n = 15) or wedge resection or lobectomy (n = 6). The formalin and B5-fixed, hematoxylin and eosin-stained histologic sections, immunophenotyping studies and immunohistochemical (IHC) staining of the lung biopsy specimens were evaluated by pathologists using the WHO classification system [14]. Immunophenotyping studies were performed to support accurate diagnosis using antibodies to Ki-67, CD3, CD5, CD10, CD19, CD20, CD22, CD23, CD45 and CD79a selectively according to suspected subtype. Supplemental IHC staining using antibodies to CD4, CD8, CD21, CD30, CD43, CD56, cyclinD1, BCL-2, BCL-6, epithelial membrane antigen (EMA), anaplastic lymphoma kinase (ALK) and immunoglobulin was performed in selected cases when initial phenotyping failed to definitively support the specific diagnosis. Nineteen patients (51.4%) had MALT lymphoma, 13 (35.1%) had DLBCL, 2 each (5.4%) had anaplastic cell lymphoma and mantle cell lymphoma, and 1 (2.7%) had Burkitt’s lymphoma. The 37 patients were divided into two groups: MALT and non-MALT lymphoma. Patients with DLBCL, anaplastic cell lymphoma, mantle cell lymphoma and Burkitt’s lymphoma were all categorized as non-MALT lymphoma. The tumors were also categorized as primary (n = 15), secondary (n = 15) or recurrent (n = 7). Primary pulmonary lymphoma is defined as unilateral or bilateral lung lymphoma without past history of lymphoma and absence of extrathoracic disease up to 3 months after the initial diagnosis [3, 8, 13]. Secondary pulmonary lymphoma is defined as either pulmonary involvement during the course of the first 3 months of systemic lymphoma or pulmonary lymphoma induced by chemotherapy or radiation therapy [3, 13, 15]. Recurrence is defined as lung involvement that appeared after a therapy-induced disease-free period [8]. The four cases of lymphoma excluded in this report included primary in 3 cases (2 MALT lymphomas and 1 anaplastic B cell lymphoma) and recurrent diffuse large B cell lymphoma (DLBCL) in the fourth. CT images were assessed by two radiologists with 32 and 8 years of experience, respectively. Discordances were solved by consensus. Thoracic CT images of each patient were reviewed with respect to the following findings: consolidation, air-bronchograms, ground-glass opacity (GGO), CT-halo sign, lymphadenopathy, nodules, reticular opacities, and pleural effusion. Lymph nodes that were round in shape, with irregular borders, absent fatty hilum, heterogeneous or necrotic in content, and greater than 1 cm in their short-axis diameter were considered lymphadenopathy [16]. Statistical analysis All continuous variables were presented as median and inter-quartile ranges (IQR); categorical variables were presented as numbers and percentages. Differences in continuous variables between two groups were tested by the Mann–Whitney U test. The Kruskal Wallis test was used to analyze differences between continuous variables between more than two groups. Fisher’s exact test was used to test associations of categorical variables between two groups. A two tailed p-value of less than < 0.05 was considered statistically significant. All statistical analyses were performed with SAS 9.1 software (SAS Institute Inc, Cary, NC, USA).