A retrospective study on the clinical characteristics and radiological features of primary pulmonary lymphoma

Differential clinical and CT imaging features of pneumonic-type primary pulmonary lymphoma and pneumonia: a retrospective multicentre observational study

INTRODUCTION

Pneumonic-type primary pulmonary lymphoma (PPL) is often misdiagnosed as pneumonia in clinical practice. However, this disease requires different treatments, which calls for a correct diagnosis.

MATERIALS AND METHODS

A total of 227 patients with pneumonic-type PPL (n=72) and pneumonia (n=155) from 7 institutions were retrospectively enrolled between January 2017 and January 2022. Clinical features (age, sex, cough, sputum, fever, haemoptysis, chest pain, smoking, weight loss and laboratory results (haemoglobin, white blood cell count, C reactive protein level and erythrocyte sedimentation rate)) and CT imaging characteristics (air bronchogram, bronchiectasis, halo sign, pleural traction, pleural effusion, lymphadenopathy, lesion maximum diameter and CT attenuation value) were analysed. Receiver operating characteristic curve analysis was performed for model construction based on independent predictors in identifying pneumonic-type PPL. In addition, we used a calibration curve and decision curve analysis to estimate the diagnostic efficiency of the model.

RESULTS

The patients with pneumonia showed a higher prevalence of sputum, fever, leucocytosis and elevation of C reactive protein level than those with pneumonic-type PPL (p=0.002, p<0.001, p=0.011 and p<0.001, respectively). Bronchiectasis, halo sign and higher CT attenuation value were more frequently present in pneumonic-type PPL than in pneumonia (all p<0.001). Pleural effusion was more commonly observed in patients with pneumonia than those with pneumonic-type PPL (p<0.001). Also, sputum, fever, elevation of C reactive protein level, halo sign, bronchiectasis, pleural effusion and CT attenuation value were the independent predictors of the presence of pneumonic-type PPL with an area under the curve value of 0.908 (95% CI, 0.863 to 0.942).

CONCLUSION

Pneumonic-type PPL and pneumonia have different clinical and imaging features. These differential features could be beneficial in guiding early diagnosis and subsequent initiation of therapy.

Development and validation of a CT-based radiomics model for differentiating pneumonia-like primary pulmonary lymphoma from infectious pneumonia: A multicenter study

BACKGROUND

Pneumonia-like primary pulmonary lymphoma (PPL) was commonly misdiagnosed as infectious pneumonia, leading to delayed treatment. The purpose of this study was to establish a computed tomography (CT)-based radiomics model to differentiate pneumonia-like PPL from infectious pneumonia.

METHODS

In this retrospective study, 79 patients with pneumonia-like PPL and 176 patients with infectious pneumonia from 12 medical centers were enrolled. Patients from center 1 to center 7 were assigned to the training or validation cohort, and the remaining patients from other centers were used as the external test cohort. Radiomics features were extracted from CT images. A three-step procedure was applied for radiomics feature selection and radiomics signature building, including the inter- and intra-class correlation coefficients (ICCs), a one-way analysis of variance (ANOVA), and least absolute shrinkage and selection operator (LASSO). Univariate and multivariate analyses were used to identify the significant clinicoradiological variables and construct a clinical factor model. Two radiologists reviewed the CT images for the external test set. Performance of the radiomics model, clinical factor model, and each radiologist were assessed by receiver operating characteristic, and area under the curve (AUC) was compared.

RESULTS

A total of 144 patients (44 with pneumonia-like PPL and 100 infectious pneumonia) were in the training cohort, 38 patients (12 with pneumonia-like PPL and 26 infectious pneumonia) were in the validation cohort, and 73 patients (23 with pneumonia-like PPL and 50 infectious pneumonia) were in the external test cohort. Twenty-three radiomics features were selected to build the radiomics model, which yielded AUCs of 0.95 (95% confidence interval [CI]: 0.94-0.99), 0.93 (95% CI: 0.85-0.98), and 0.94 (95% CI: 0.87-0.99) in the training, validation, and external test cohort, respectively. The AUCs for the two readers and clinical factor model were 0.74 (95% CI: 0.63-0.83), 0.72 (95% CI: 0.62-0.82), and 0.73 (95% CI: 0.62-0.84) in the external test cohort, respectively. The radiomics model outperformed both the readers' interpretation and clinical factor model ( P <0.05).

CONCLUSIONS

The CT-based radiomics model may provide an effective and non-invasive tool to differentiate pneumonia-like PPL from infectious pneumonia, which might provide assistance for clinicians in tailoring precise therapy.

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.

With the Increasing Health Awareness: Clinical and Computed Tomography Findings in Primary Pulmonary Mucosa-Associated Lymphoid Tissue Lymphoma Lymphoma

OBJECTIVE

The objective of this study is to investigate the clinical manifestations, computed tomography (CT) findings, and prognosis of primary pulmonary mucosa-associated lymphoid tissue lymphoma (MALToma) with the improved health awareness nowadays.

METHODS

Clinical data and CT images of patients with pathologically confirmed MALToma from October 2012 to October 2021 were retrospectively analyzed.

RESULTS

Eighteen MALToma patients were included in the study (8 men and 10 women; mean age, 56.17 years; range, 33-73 years). Six men had a long-term history of smoking (>20 years). One patient had an autoimmune disease (Sjögren syndrome). Eight patients (44.44%) were asymptomatic, and 10 (55.56%) had mild chest or systemic symptoms. Most lesions (88.89%) were subpleural or located along the bronchovascular tree. According to the CT characteristics, the lesions were divided into 4 groups: nodular type (n = 8; 44.44%, including 5 solid nodules and 3 ground-glass nodules), mass type (n = 4, 22.22%), patch or consolidate type (n = 5, 27.78%), and mixed type (n = 1, 5.56%). Air bronchogram (11/18, 61.11%) and angiogram sign (8/16, 50%) were the most frequent CT findings and may help differential diagnosis. The patients were misdiagnosed with lung cancer (n = 11, 61.11%), inflammatory or chronic inflammatory disease (n = 4, 22.22%), bronchiectasis accompanied by infection (n = 1, 5.56%), diffuse interstitial lung disease (n = 1, 5.56%), and granuloma or tuberculosis (n = 1, 5.56%). The prognosis of all patients was favorable; 1 patient was lost to follow-up.

CONCLUSIONS

Nowadays, patients with MALToma are usually asymptomatic or paucisymptomatic. Nodular lesions, including ground-glass nodules, are the most common presentation. Mucosa-associated lymphoid tissue lymphoma is most likely misdiagnosed as lung cancer. Lesions located in the subpleural areas or along the bronchovascular tree and presenting with an air bronchogram or angiogram sign could indicate a MALToma diagnosis.

Primary Pulmonary Small B-Cell Non-Hodgkin Lymphoma -Case Presentation-

Primary pulmonary non-Hodgkin lymphoma is a rare entity, accounting for 3-4% of extranodal non-Hodgkin lymphomas. Indolent primary pulmonary non-Hodgkin lymphomas are the most frequent types, with the MALT subtype representing majority of cases. Other indolent subtypes of B-cell primary pulmonary lymphomas are rare. We present the case of a 56-year-old patient, non-smoker, who presents for pain in the right hemithorax, worsened by deep inhales. Pulmonary X-ray showed a right paramediastinal superior and medial lobe homogenous opacity with faded contour. Thoracic computed tomography scan described a dense right superior mediastino-pulmonary tumoral mass, the absence of hilar or mediastinal adenopathies. In this context, an ultrasound-guided transbronchial needle aspiration was performed. Histopathology and immunohistochemistry confirmed the diagnosis of primary pulmonary small B-cell non-Hodgkin lymphoma. After 6 chemotherapy cycles, from a clinical and imagistic (thoracic CT scan) point of view, the response was favourable. Positron emission tomography (PET/CT) aspect indicated a complete metabolic response to treatment.