Pulmonary mucosa-associated lymphoid tissue lymphoma: CT findings and pathological basis

Usefulness and Limitations of Current Diagnostic Strategies for Pulmonary Mucosa-Associated Lymphoid Tissue Lymphoma: Lessons Learned From a Large Cohort

CONTEXT.—

The pathologic diagnosis of pulmonary extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) is challenging.

OBJECTIVE.—

To evaluate the diagnostic usefulness and limitations of current diagnostic strategies for pulmonary MALT lymphoma.

DESIGN.—

A retrospective review of 120 cases of pulmonary MALT lymphoma from 2014 through 2021 was performed.

RESULTS.—

Clinicoradiologic presentations overlapped with previous observations in patients with MALT lymphoma, such as a wide age range, female predominance, frequent association with autoimmune disease or immunodeficiency, and broad imaging findings. The histopathologic diagnosis was based on a combination of morphology, immunohistochemistry, and demonstration of B-cell lineage clonality. Two-thirds (76 of 113) of MALT lymphomas had lymphoplasmacytoid cytomorphology. Occasionally, MALT lymphomas were associated with granulomas/giant cells (29%, 35 of 120) or immunoglobulin deposition disease (21%, 25 of 120), including light chain/heavy chain deposition disease, amyloidosis, and/or crystal storing histiocytosis. While CD5, CD10, Bcl-2, and Bcl-6 rarely revealed aberrancies, aberrant CD43 expression either on B-cells or on plasma cells was detected in 42% (27 of 64) of cases, including cases for which proof of clonality could not be obtained. κ/λ in situ hybridization was particularly useful for tumors with lymphoplasmacytoid morphology but performed poorly in lymphomas having no plasmacytic differentiation. κ/λ immunohistochemistry showed no additional usefulness when applied together with κ/λ in situ hybridization. Immunoglobulin gene rearrangement studies by polymerase chain reaction achieved high detection rates of clonality in all cytomorphologic subgroups.

CONCLUSIONS.—

Our study offers a practical evaluation of common diagnostic tests in pulmonary MALT lymphoma. We offer recommendations for a diagnostic workup that takes into consideration the usefulness and the specific limitations of the various diagnostic strategies.

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.

Diagnostic Approach to Pulmonary B-Cell Lymphomas in Small Biopsies, with Practical Recommendations to Avoid Misinterpretation

Pulmonary lymphomas are rare. With the current less invasive approaches used to obtain material for diagnosis, the diagnosis of pulmonary lymphoma is now frequently established in a small biopsy rather than in a resection. Therefore, the diagnosis has become more challenging and requires correlation with the clinico-radiologic presentation and with ancillary studies (immunohistochemistry, flow cytometry, cytogenetics, and/or molecular analysis). Due to the rarity of pulmonary lymphomas, clinical suspicion of a lymphomatous process is low at initial presentation, and material may be only submitted for histopathology. For this reason, herein, we provide recommendations to arrive at the correct diagnosis of the most common lung B-cell lymphomas (marginal zone lymphoma of mucosa-associated lymphoid tissue, diffuse large B-cell lymphoma, intravascular large B-cell lymphoma, lymphomatoid granulomatosis) in the setting of small biopsies, utilizing only immunohistochemistry. The differential diagnosis varies according to the lymphoma subtype and includes reactive conditions, solid tumors, and other hematolymphoid malignancies. Although morphology and immunohistochemistry may be sufficient to establish a diagnosis, in some cases, the best recommendation is to obtain additional tissue via a VATS biopsy/wedge resection with material submitted for flow cytometry, cytogenetics, and/or molecular studies to be able to properly classify a pulmonary lymphoid process.

Evaluation of CT features for differentiating consolidation pattern of pulmonary MALT lymphoma from pneumonic-type lung adenocarcinoma

Purpose

In clinical practice, the consolidation pattern of pulmonary mucosa-associated lymphoid tissue (C-MALT) was often misdiagnosed as pneumonic-type lung adenocarcinoma (P-LADC). However, the mainstay of treatment and prognosis of these two diseases are different. The purpose of this study was to distinguish C-MALT from P-LADC by pre-treatment chest computed tomography (CT) features.

Patients and methods

A total of 31 patients with C-MALT (15 men and 16 women; mean age, 61.1 ± 11.2 years) and 58 patients with P-LADC (34 men and 24 women; mean age, 68.6 ± 7.4 years) confirmed by pathology who underwent contrast-enhanced chest CT were retrospectively enrolled from September 2014 to February 2023. Detailed clinical and CT characteristics of the two groups were evaluated. Logistic regression analysis was used to assess the effectiveness of statistically significant variables in distinguishing C-MALT from P-LADC.

Results

The average age of C-MALT was younger than P-LADC patients (p<0.001). With regard to CT features, bronchiectasis within the consolidation was more common in the C-MALT group than the P-LADC group [83.87% (26 of 31) vs 20.69% (12 of 58), p<0.001]; whereas lymph nodes enlargement [75.86% (44 of 58) vs 9.68% (3 of 31), p<0.001] and pleural effusion [43.10% (25of 58) vs 19.35% (6 of 31), p=0.025] were more frequently observed in the P-LADC group than C-MALT group. The predictors with p<0.05 (age, bronchiectasis, lymph node enlargement, and pleural effusion) were used to construct a logistic regression model in discriminating C-MALT from P-LADC, the area under curve (AUC), positive predictive value (PPV), negative predictive value (NPV), specificity, sensitivity, and accuracy were 0.9555, 86.67%, 91.53%, 83.87%, 93.10%, and 89.89%, respectively.

Conclusion

C-MALT and P-LADC have differential clinical and CT features. An adequate understanding of these different characteristics can contribute to the early accurate diagnosis of C-MALT and provide an appropriate therapeutic strategy.

Radiological and pathological analysis of the galaxy sign in patients with pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma

BACKGROUND

Pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma sometimes presents as large pulmonary nodules composed of small nodular opacities (galaxy sign) on computed tomography (CT). The aim of this study was to assess the presence, usefulness, and pathological characteristics of the galaxy sign on CT of pulmonary MALT lymphoma.

METHODS

From January 2011 to December 2021, chest CTs of 43 patients with pulmonary MALT lymphoma were reviewed by two radiologists for the galaxy sign and various other findings. Interreader agreement to characterize the galaxy sign and factors associated in making a correct first impression on CT prior to pathological diagnosis were assessed. Resected specimens were reviewed by two pathologists, and the proportion of peripheral lymphoma infiltrates was compared between lesions with and without the galaxy sign.

RESULTS

Of 43 patients, 22 patients (44.2%) showed the galaxy sign (κ = 0.768, p < 0.0001). The galaxy sign (p = 0.010) was associated with making a correct first impression on CT prior to pathological diagnosis. On pathological examination, lesions showing the galaxy sign on CT demonstrated a significantly higher proportion of peripheral lymphoma infiltrates (p = 0.001).

CONCLUSION

The galaxy sign can be seen on CT of pulmonary MALT lymphoma with a higher proportion of peripheral lymphoma infiltrates and may be useful in making a correct diagnosis of pulmonary MALT lymphoma.

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.

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.

Evaluation of HRCT for the Differential Diagnosis of Pneumonia-Like Consolidation Pattern of Pulmonary MALT Lymphoma from Lobar Pneumonia

Purpose

To assess the performance of high-resolution computed tomography (HRCT) in discriminating the consolidation pattern of pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma from lobar pneumonia.

Patients and Methods

This retrospective study comprised 26 patients with pathologically confirmed consolidation pattern of pulmonary MALT lymphoma (12 men and 14 women; mean age, 59.4±12.1 years) and 36 patients with lobar pneumonia confirmed by body fluids or respiratory secretion culture (16 men and 20 women; mean age, 41.8±26.3 years). Two radiologists independently evaluated the CT images. The effectiveness of these variables in distinguishing lobar pneumonia from MALT lymphoma was analyzed using logistic regression analysis.

Results

The average age of lobar pneumonia patients was younger than that of MALT lymphoma patients (p=0.002). The respiratory symptom was more common in lobar pneumonia than MALT lymphoma (p=0.002). Signs of bronchiectasis within the consolidation and bulging of interlobar fissure occurred significantly more often in MALT lymphoma than pneumonia (69.2% vs 11.1%, p<0.0001; 46.2% vs 19.4%, p=0.024). We used the predictors with p<0.05 (age, respiratory symptoms, bronchiectasis, and bulging of interlobar fissure) to construct a logistic regression model. The area under curve (AUC), negative predictive value (NPV), positive predictive value (PPV), sensitivity, specificity, and accuracy were 0.891, 84.21%, 83.33%, 88.89%, 76.92%, and 83.87% for discriminating lobar pneumonia from MALT lymphoma.

Conclusion

Middle-aged, presence of mild clinical symptoms, bronchiectasis and bulging of the interlobar fissure on chest CT images are potential markers to distinguish pulmonary MALT lymphoma from lobar pneumonia.