Significance of imaging and clinical features in the differentiation between primary and secondary pulmonary lymphoma

Pulmonary extranodal natural killer/T-cell lymphoma: clinical presentation, CT characteristics, and patient outcomes

Background

Due to the extreme rarity of pulmonary extranodal natural killer/T-cell lymphoma (ENKTCL), studies on this lymphoma type are limited. We aimed to investigate the clinical presentations, computed tomography (CT) findings, CT dynamic changes, and outcomes of patients diagnosed with pulmonary ENKTCL.

Methods

We conducted a retrospective cohort study on ENKTCL, nasal type, at West China Hospital, from January 2010 to January 2023. Out of 27 initial cases with pulmonary ENKTCL, we excluded 4 due to the lack of chest CT images, resulting in a final cohort of 23 patients. Our evaluation covered clinical features, laboratory findings, CT presentations, treatment strategies, and survival outcomes. Survival analyses were performed using the Kaplan-Meier method, with log-rank tests for survival curve comparisons. Given the small sample size, our interpretation of the data is mainly descriptive.

Results

The most common CT presentations in our institution was solitary or multiple nodules (7/23, 30.4%). The halo sign (78.3%) and floating vessels sign (83.3%) were commonly observed in pulmonary ENKTCL. Elevated lactate dehydrogenase (LDH) levels were observed in 20 (86.9%) patients. The median overall survival (OS) for pulmonary ENKTCL patients was 1 month; 3 cases displayed a favorable prognosis, maintaining complete remission (CR) status for 1.5-7 years after receiving chemotherapy. Chemotherapy led to improved prognosis, with a median survival of 5 months seen in patients who received chemotherapy. Patients with bilateral lung involvement had worse outcomes compared to those with unilateral lesions.

Conclusions

Pulmonary ENKTCL is a rare and aggressive disease, often misdiagnosed due to nonspecific clinical and CT features. Laboratory tests, failure of antibiotic treatment, and "floating vessels sign" on enhanced CT scans may aid in diagnosis. Timely chemotherapy may improve survival, emphasizing the importance of early detection and prompt treatment.

Role of 18F-FDG PET/CT in patients affected by pulmonary primary lymphoma

Background

Primary pulmonary lymphoma (PPL) is defined as clonal abnormal hyperplasia of lung parenchyma or bronchial lymphoid tissue originating from bronchial mucosal tissue. However, PPL is rare, which accounts for approximately 3-4% of extraneurotic lymphomas and 0.5-1% of all primary tumors in the lung. Owing to the lack of any typical clinical symptoms and radiological features, it is challenging to accurately diagnose PPL, which affects its clinical management and prognosis. Considering this, herein, we aim to raise awareness of this disease and help physicians understand the role of 18F-FDG PET/CT in the diagnosis of PPL.

Method

A retrospective analysis was performed on the clinical and 18F-FDG PET/CT imaging data of 19 patients diagnosed with PPL by biopsy pathology at our hospital from April 2014 to December 2021.

Results

Of the 19 PPL patients, 15 patients showed clinical symptoms with the most common being fever and cough. In addition, there were 4 cases that had no clinical symptoms, and all of them were MALT lymphoma. In fact, 16 patients were misdiagnosed as lobar pneumonia, lung cancer, tuberculosis, and diffuse interstitial inflammation, representing a misdiagnosis rate of 84.2%. Also, 73.7% were MALT lymphomas, representing the most common pathological pattern, along with 3 DLBCL and 2 T-cell lymphomas. With reguard to CT signs, the air-bronchial sign was found to be the most common, followed by the halo sign and the collapsed leaf sign. On the basis of the predominant radiologic features, lesions were categorized as pneumonic consolidation, nodular/mass type, diffuse interstitial type, and mixed type. The average SUVmax of lesions was 7.23 ± 4.75, the ratio of SUVmax (lesion/liver) was 3.46 ± 2.25, and the ratio of SUVmax (lesion/mediastinal blood pool) was found to be 5.25 ± 3.27. Of interest, the different pathological types of PPL showed different values of 18F-FDG uptake. The 18F-FDG uptake of DLCBL was the most prominent with a SUVmax of 15.33 ± 6.30 and was higher than that of MALT lymphoma with a SUVmax of 5.74 ± 2.65. There appeared similarity in 18F-FDG uptake between MALT lymphoma and T-cell lymphoma. For the SUVmax of lesion, we found statistical significance between MALT lymphoma and DLCBL (P value<0.001). In addition, we also found statistical significance (P value < 0.05) in SUVmax of lesions between pneumonic consolidation type and nodal/mass type, I stage, and other stages.

Conclusions

On 18F-FDG PET/CT images, certain features of PPL morphology and metabolism can be identified that may contribute to a better understanding of this disease. In addition, 18F-FDG PET/CT whole-body imaging has the potential to refine the staging of PPL. Most importantly, functional 18F-FDG PET/CT imaging can readily reflect tumor cell activity, thus allowing for the selection of an optimal biopsy site.

The characteristic computed tomography findings of pulmonary B-cell non-Hodgkin's lymphoma and their role in predicting patient survival

Background

To assess the value of characteristic computed tomography (CT) findings in predicting the survival of patients with pulmonary B-cell non-Hodgkin's lymphoma (NHL).

Methods

Eighty-four patients who were histopathologically confirmed with pulmonary B-cell NHL between 2004 and 2018 were retrospectively enrolled. All patients underwent chest CT scan at the time of initial diagnosis in our hospital. Characteristic CT findings and clinicopathological features of the patients were analyzed, and Cox regression models were used to determine the relationship of CT findings with overall survival (OS) and progression-free survival (PFS).

Results

Air bronchogram occurred more frequently in patients with early-stage disease, primary pulmonary lymphoma (PPL) and the indolent histological type of lymphoma than in patients with advanced-stage disease, secondary pulmonary lymphoma (SPL), and the aggressive histological type (all P<0.05). The halo sign was observed most in the SPL group (19/48, 40%; P=0.004), while the presence of cross-lobe sign was higher in patients with PPL (13/36, 36%; P=0.010). Pleural involvement and hilar/mediastinal lymphadenopathy were observed more in patients with SPL and the aggressive histological type (33/48 and 27/48; 31/46 and 26/46, respectively; all P<0.05). Survival analyses showed that the number of lung lesions, cross-lobe sign, and pleural involvement were independent prognostic factors for PFS, while the halo sign and pleural involvement were significantly correlated with OS (all P<0.05). More aggressive, advanced-stage cases and male patients showed worse outcomes.

Conclusions

The halo sign and pleural involvement are independent prognostic factors for OS, while the number of lung lesions, cross-lobe sign, and pleural involvement are correlated with PFS.

Primary Pulmonary Diffuse Large B Cell Lymphoma Mimicking Metastasis: A Case Report and Literature Review

Primary pulmonary diffuse large B cell lymphoma (PPDLBCL) is extremely rare, with fewer than 40 cases reported to date and a lack of systemic analysis. Herein, we present a case of PPDLBCL mimicking metastasis in a heavily treated patient with breast cancer. To our knowledge, this is the first reported case of PPDLBCL in a patient with breast cancer. A 66-year-old Chinese female diagnosed with breast cancer 7.5 years previously and multiple bone metastases 31 months later presented with a new-onset subpleural nodule in the inferior lobe of left lung detected by routine follow-up in November 2017. A 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography scan showed that the pulmonary nodule was hypermetabolic with a maximum standard uptake value of 14.9, consistent with lung metastasis in view of her history of breast cancer and multiple bone involvement. Surprisingly, pathologic investigation revealed primary lung DLBCL, staged IEA. Systemic chemotherapy with R-CDOP (rituximab, cyclophosphamide, vindesine, doxorubicin liposome, and prednisone) achieved complete remission with mild side effects. At the latest follow-up in August 2019, the patient had disease-free survival of 21 months. The findings from this case indicate that primary pulmonary lymphoma should be included in the differential diagnostic checklist of pulmonary occupancy, even in solid tumor patients treated with multiple modalities. When a newly developed lung nodule is identified in such patients, clinicians should not take for granted that it is lung metastasis. Pathology results are a prerequisite for making a correct diagnosis, choosing appropriate treatment, and improving patient prognosis.

Diagnostic and prognostic factors for patients with primary pulmonary non-Hodgkin's lymphoma: A 16-year single-center retrospective study

Primary pulmonary non-Hodgkin's lymphoma (PP-NHL) is a rare entity with non-specific symptoms and radiographic findings, as well as a difficult preoperative diagnosis. A limited number of studies have described PP-NHL in Chinese patients. The goal of the present study was to improve early diagnosis by examining prognostic factors in patients with PP-NHL. Therefore, a total of 29 patients with PP-NHL were included in the study between January 2001 and June 2017, including 14 with aggressive-type and 15 with indolent-type lymphomas (10 male, 19 female; median age, 50.3 years; range, 19-87 years). Pulmonary nodules and masses (55.2%) were the most common radiographic features. The diagnostic yield was 80% (12/15) by endobronchial biopsy or transbronchial lung biopsy and 100% by computed tomography (CT)-guided percutaneous needle lung biopsy (11/11) or surgery (8/8). Elevated lactate dehydrogenase levels and systemic symptoms were observed considerably more often in patients with aggressive disease than in those with indolent disease. The 1-, 3- and 5-year overall survival (OS) rates were 42, 32, and 21%, respectively, for all patients, 72, 57 and 43%, respectively, for patients with indolent lymphomas, and 13, 6 and 0%, respectively, for patients with aggressive lymphomas. The median OS rate for all patients was 12.0 months; however, the OS rate for patients with aggressive lymphomas was significantly shorter compared with those with indolent lymphomas (7.1 months vs. 16.6 months; P=0.002). Aggressive vs. indolent lymphoma status was indicated to be an independent prognostic factor for poor 5-year OS rate (hazard ratio, 5.98; P=0.014). In conclusion, bronchoscopic and CT-guided percutaneous needle lung biopsies were the most useful and least invasive procedures for diagnosing PP-NHL. Furthermore, aggressive PP-NHL was highly associated with poor 5-year OS rate and a poor prognosis.