Pyothorax-Associated Lymphoma: Imaging Findings

Pictorial Review of Pleural Disease: Multimodality Imaging and Differential Diagnosis

The pleura is a thin, smooth, soft-tissue structure that lines the pleural cavity and separates the lungs from the chest wall, consisting of the visceral and parietal pleurae and physiologic pleural fluid. There is a broad spectrum of normal variations and abnormalities in the pleura, including pneumothorax, pleural effusion, and pleural thickening. Pneumothorax is associated with pulmonary diseases and is caused by iatrogenic or traumatic factors. Chest radiography and US help detect pneumothorax with various signs, and CT can also help assess the causes. Pleural effusion occurs in a wide spectrum of diseases, such as heart failure, cirrhosis, asbestos-related diseases, infections, chylothorax, and malignancies. Chest US allows detection of a small pleural effusion and evaluation of echogenicity or septa in pleural effusion. Pleural thickening may manifest as unilateral or bilateral and as focal, multifocal, or diffuse. Various diseases can demonstrate pleural thickening, such as asbestos-related diseases, neoplasms, and systemic diseases. CT, MRI, and fluorodeoxyglucose (FDG) PET/CT can help differentiate between benign and malignant lesions. Knowledge of these features can aid radiologists in suggesting diagnoses and recommending further examinations with other imaging modalities. The authors provide a comprehensive review of the clinical and multimodality imaging findings of pleural diseases and their differential diagnoses. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Case 322: Pyothorax-associated Lymphoma

HISTORY

An 81-year-old man living in South Korea was referred to the pulmonology clinic because of abnormal findings at routine surveillance CT. His past medical history included right radical nephroureterectomy for ureteral cancer in 2016, transurethral resection of a bladder tumor in 2015, and tuberculous pleurisy in his third decade of life that was complicated by a chronic calcified empyema. He had been doing well clinically until 6 months prior, when he presented to an outside hospital with progressive right-sided chest pain and dyspnea and was found to have active tuberculosis. During that hospitalization, he underwent chest CT and CT-guided biopsy of an incidentally found thoracic lesion, which revealed chronic active inflammation. His symptoms improved after initiation of antituberculous medication, and he was discharged home to complete treatment. Because of interval growth of this lesion noted on a subsequent surveillance CT scan, he was referred to pulmonology for further evaluation. Laboratory tests obtained during his visit revealed mild leukocytosis (1258 cells × 109/L; normal range, 4000-10 000 cells × 109/L) with neutrophilic predominance (82% neutrophils; normal range, 50%-75% neutrophils), and a mildly elevated C-reactive protein level (3.17 mg/dL; normal range, 0-0.5 mg/dL). A sputum culture was negative for tuberculosis. The patient reported mild chest discomfort and dyspnea. Liver MRI was performed to further evaluate an abnormal lesion seen at CT. Given the patient's recent nonspecific biopsy results and tuberculosis treatment, no further work-up was pursued. Contrast-enhanced chest CT was performed 6 months later because the patient developed worsening chest pain and dyspnea. He remained afebrile, with persistent leukocytosis (1485 cells × 109/L) and an elevated C-reactive protein level (3.56 mg/dL). On the basis of the imaging findings, repeat CT-guided biopsy and PET/CT were performed, thereby enabling confirmation of the diagnosis, and appropriate treatment was initiated.

Primary pleural epithelioid angiosarcoma manifesting as a loculated hemothorax: A case report and literature review focusing on CT findings

Primary pleural angiosarcoma (PPA) is an extremely rare and clinically aggressive tumor. We report the case of a 66-year-old man having PPA with chest computed tomography (CT) scan showing a large oval-shaped, nonenhancing high attenuation cystic mass in the left hemithorax. Morphological and immunohistochemical findings supported the diagnosis of epithelioid angiosarcoma. Pleural angiosarcoma should be considered in the differential diagnosis of spontaneous hemothorax manifesting as high attenuation loculated pleural fluid on CT.

Sarcomatoid carcinoma associated with chronic empyema and early lung and pleural metastases: A case report

INTRODUCTION

The relationship between chronic empyema and malignant tumors, most of which are lymphoma, has been recognized for many decades. Sarcomatoid carcinoma associated with chronic empyema is extremely rare, may metastasize to other organs in the early stage, and rapidly progresses to death. As far as we know, this was the first case report on sarcomatoid carcinoma associated chronic empyema.

THE PATIENTS MAIN CONCERNS AND IMPORTANT CLINICAL FINDINGS

A 59-year-old man presented to our hospital with a 9-year history of chronic empyema and a chief complaint of left chest wall pain for 5 months. The diagnostic contrast-enhanced computed tomography (CT) showed a large irregular soft tissue mass located on the left lower hemithorax at the margin of the empyema cavity extending to the adjacent chest wall and lung parenchyma. In addition, CT revealed pleural and pulmonary metastases surrounded by ground glass opacity.

THE MAIN DIAGNOSIS, THERAPEUTICS INTERVENTIONS, AND OUTCOMES

The patient underwent CT guided percutaneous core needle biopsy (PCNB). The histopathological evaluation showed carcinomatous proliferation of pleomorphic spindle cells with extensive necrosis. Immunohistochemically, tumor cells were positive for cytokeratin and vimentin. The final histopathological diagnosis was sarcomatoid carcinoma underlying chronic empyema. The tumors showed rapid progression on serial simple radiography. Palliative treatments were performed, but the patient still developed severe dyspnea and died shortly after on day 16.

CONCLUSION

Sarcomatoid carcinoma can occur very rarely as a complication of chronic empyema, and is more aggressive than usual. Early detection of developing malignancy during the follow-up of chronic empyema is an important factor for patient prognosis.

Primary Mediastinal Nodal and Extranodal Non-Hodgkin Lymphomas: Current Concepts, Historical Evolution, and Useful Diagnostic Approach: Part 1

Primary mediastinal non-Hodgkin lymphomas (PM-NHLs) represent ~5% of all NHLs and comprise lymphomas of B-cell and T-cell origin. PM-NHLs are defined as involvement of mediastinal lymph nodes, thymus, and/or mediastinal organs (heart, lung, pleura, pericardium) by NHL without evidence of systemic disease at presentation. The clinical scenario is variable and depends on the lymphoma subtype. The radiologic presentation is also variable ranging from a mediastinal mass with or without superior vena cava syndrome, a pleural or a cardiac mass associated with an effusion, or as an effusion only. The diagnosis of PM-NHLs can only be established by microscopic evaluation, and therefore, general pathologists should be aware of these tumors and familiar with their diagnostic approach. The most common anterior mediastinal NHLs (90% to 95%) are primary mediastinal large B-cell lymphoma and T lymphoblastic lymphoma. Thymic marginal zone lymphoma and mediastinal gray zone lymphoma are very rare. The remainder PM-NHLs involving middle or posterior mediastinum include diffuse large B-cell lymphoma (DLBCL) and rare cases of T-cell lymphoma, including anaplastic large cell lymphoma and breast implant-associated anaplastic large cell lymphoma extending to the anterior mediastinum. Primary pleural and cardiac NHLs are mostly DLBCLs. Other rare subtypes of PM-NHLs include DLBCL associated with chronic inflammation/pyothorax-associated lymphoma, fibrin-associated DLBCL (both EBV), and pleural and/or pericardial primary effusion lymphoma (HHV-8/EBV). We review the historical aspects, epidemiology, clinico-radiologic features, histopathology, immunohistochemistry, differential diagnosis, and relevant cytogenetic and molecular features of PM (thymic) LBCL, PM "nonthymic" DLBCL, BCL, unclassifiable, with features intermediate between DLBCL and classic Hodgkin lymphoma (mediastinal gray zone lymphoma), DLBCL associated with chronic inflammation (pyothorax-associated lymphoma), fibrin-associated DLBCL, and primary effusion lymphoma. This review represents the first part of 2 manuscripts covering PM-NHLs.

Diagnostic Performance of ¹⁸F-Fluorodeoxyglucose Positron Emission Tomography/CT for Chronic Empyema-Associated Malignancy

OBJECTIVE

The purpose of this study was to evaluate the diagnostic performance of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) for chronic empyema-associated malignancy (CEAM).

MATERIALS AND METHODS

We retrospectively reviewed the ¹⁸F-FDG PET/CT images of 33 patients with chronic empyema, and analyzed the following findings: 1) shape of the empyema cavity, 2) presence of fistula, 3) maximum standardized uptake value (SUV) of the empyema cavity, 4) uptake pattern of the empyema cavity, 5) presence of a protruding soft tissue mass within the empyema cavity, and 6) involvement of adjacent structures. Final diagnosis was determined based on histopathology or clinical follow-up for at least 6 months. The abovementioned findings were compared between the ¹⁸F-FDG PET/CT images of CEAM and chronic empyema. A receiver operating characteristic (ROC) analysis was also performed.

RESULTS

Six lesions were histopathologically proven as malignant; there were three cases of diffuse large B-cell lymphoma, two of squamous cell carcinoma, and one of poorly differentiated carcinoma. Maximum SUV within the empyema cavity (p < 0.001) presence of a protruding soft tissue mass (p = 0.002), and involvement of the adjacent structures (p < 0.001) were significantly different between the CEAM and chronic empyema images. The maximum SUV exhibited the highest diagnostic performance, with the highest specificity (96.3%, 26/27), positive predictive value (85.7%, 6/7), and accuracy (97.0%, 32/33) among all criteria. On ROC analysis, the area under the curve of maximum SUV was 0.994.

CONCLUSION

¹⁸F-FDG PET/CT can be useful for diagnosing CEAM in patients with chronic empyema. The maximum SUV within the empyema cavity is the most accurate ¹⁸F-FDG PET/CT diagnostic criterion for CEAM.

Primary Extranodal Lymphoma of the Thorax

Primary pulmonary lymphomas represent a pathologically heterogeneous group of disorders that often share imaging features, which include peribronchovascular nodules and masses or areas of nonresolving consolidation. Primary mediastinal B-cell lymphoma is an extranodal non-Hodgkin lymphoma seen in younger patients that has imaging and pathologic features that demonstrate some degree of overlap with Hodgkin lymphoma. Primary lymphomas of the pleural space are rare and associated with concomitant viral infections.

Diffuse Large B-cell Lymphoma Arising from Chronic Tuberculous Empyema

Pyothorax-associated lymphoma is a relatively rare type of lymphoma that occurs in patients who have long histories of tuberculous pleuritis or induced pneumothorax. It is a type of non-Hodgkin’s lymphoma of mainly the B-cell phenotype and is strongly associated with Epstein–Barr virus infection. A majority of these cases have been reported in Japan, although some cases have occurred in Western countries. Here, we describe a case of pyothorax-associated lymphoma in a patient with a 30-year history of chronic tuberculous empyema. The patient underwent decortication under the impression of chronic empyema with fistula. The histopathologic diagnosis was a diffuse large B-cell lymphoma associated chronic inflammation.

Multimodality imaging of cardiothoracic lymphoma

Lymphoma is the most common hematologic malignancy and represents approximately 5.3% of all cancers. The World Health Organization published a revised classification scheme in 2008 that groups lymphomas by cell type and molecular, cytogenetic, and phenotypic characteristics. Most lymphomas affect the thorax at some stage during the course of the disease. Affected structures within the chest may include the lungs, mediastinum, pleura, and chest wall, and lymphomas may originate from these sites as primary malignancies or secondarily involve these structures after arising from other intrathoracic or extrathoracic sources. Pulmonary lymphomas are classified into one of four types: primary pulmonary lymphoma, secondary pulmonary lymphoma, acquired immunodeficiency syndrome-related lymphoma, and post-transplantation lymphoproliferative disorders. Although pulmonary lymphomas may produce a myriad of diverse findings within the lungs, specific individual features or combinations of features can be used, in combination with secondary manifestations of the disease such as involvement of the mediastinum, pleura, and chest wall, to narrow the differential diagnosis. While findings of thoracic lymphoma may be evident on chest radiography, computed tomography has traditionally been the imaging modality used to evaluate the disease and effectively demonstrates the extent of intrathoracic involvement and the presence and extent of extrathoracic spread. However, additional modalities such as magnetic resonance imaging of the thorax and (18)F-FDG PET/CT have emerged in recent years and are complementary to CT in the evaluation of patients with lymphoma. Thoracic MRI is useful in assessing vascular, cardiac, and chest wall involvement, and PET/CT is more accurate in the overall staging of lymphoma than CT and can be used to evaluate treatment response.

Crosstalk between the mesothelium and lymphomatous cells: insight into the mechanisms involved in the progression of body cavity lymphomas

The peculiar localization of body cavity lymphomas implies a specific contribution of the intracavitary microenvironment to the pathogenesis of these tumors. In this study, primary effusion lymphoma (PEL) was used as a model of body cavity lymphoma to investigate the role of mesothelial cells, which line the serous cavities, in lymphoma progression. The crosstalk between mesothelial and lymphomatous cells was studied in cocultures of primary human mesothelial cells (HMC) with PEL cells and a xenograft mouse model of peritoneal PEL. PEL cells were found to induce type 2 epithelial–mesenchymal transition (EMT) in HMC, which converted into a myofibroblastic phenotype characterized by loss of epithelial markers (pan cytokeratin and E-cadherin), expression of EMT-associated transcriptional repressors (Snail1, Slug, Zeb1, Sip1), and acquisition of α-smooth muscle actin (α-SMA), a mesenchymal protein. A progressive thickening of serosal membranes was observed in vivo, accompanied by loss of cytokeratin staining and appearance of α-SMA-expressing cells, confirming that fibrosis occurred during intracavitary PEL development. On the other hand, HMC were found to modulate PEL cell turnover in vitro, increasing their resistance to apoptosis and proliferation. This supportive activity on PEL cells was retained after transdifferentiation, and was impaired by interferon-α₂b treatment. On the whole, our results indicate that PEL cells induce type 2 EMT in HMC, which support PEL cell growth and survival, providing a milieu favorable to lymphoma progression. Our findings provide new clues into the mechanisms involved in lymphoma progression and may indicate new targets for effective treatment of malignant effusions growing in body cavities.

A case of chronic expanding hematoma resulting in fatal hemoptysis

An 80-year-old woman presented with a huge intrathoracic mass which had increased in size over 4 years. Computed tomography showed a thick calcified capsule and early-enhanced streaks inside the mass. Needle biopsy aspirated pure blood and fibrous connective tissue. F-18 fluorodeoxyglucose positron-emission tomography showed moderate FDG uptake at the periphery with central photon defects. Gallium-67 scintigraphy showed no abnormal uptake. On suspicion of chronic expanding hematoma, we recommended surgical resection, but the patient requested only follow-up. One year later, she was hospitalized with cardiac tamponade and subsequent massive hemoptysis. Repeated embolization was ineffective, and the patient soon succumbed.

Tuberculosis versus lymphoma in the abdominal lymph nodes: a comparative study using contrast-enhanced MRI

PURPOSE

The purpose of this study was to determine the differential characteristics on MRI between tuberculosis and lymphoma in abdominal lymph nodes.

MATERIALS AND METHODS

We conducted a retrospective analysis for the counter, size, signal intensity, enhancement patterns, and anatomic distribution of lymph nodes in 57 consecutive patients with documented tuberculosis (28 patients; 49.1%) and newly diagnosed, untreated lymphoma (29 patients; 50.9%).

RESULTS

Twenty-four cases (85.7%) in the tuberculosis group were hyperintense on T2-weighted images and either hypointense or isointense on T1-weighted images with respect to the abdominal wall muscle. All cases in the lymphoma group were hyperintense on T2-weighted images and isointense on T1-weighted images with respect to the abdominal wall muscle. Concerning the main anatomic distribution of lymph nodes, the lymph nodes in the lower paraaortic region were more frequently involved in the lymphoma group (48.3%) than in tuberculosis (17.9%, p<0.05). Moreover, mesenteric lymph nodes were more often involved in tuberculosis (32.1%) than in lymphoma (6.9%, p<0.05). Tuberculous lymphadenopathy showed predominantly peripheral enhancement, frequently with a multilocular appearance; whereas lymphomatous adenopathy often demonstrated uniform homogeneous enhancement (all p<0.001).

CONCLUSION

Contrast-enhanced MRI can be useful in differentiation between these two entities.

Usefulness of (18)F-FDG positron emission tomography/computed tomography for the diagnosis of pyothorax-associated lymphoma: A report of three cases

Pyothorax-associated lymphoma (PAL) is a unique and rare non-Hodgkin's lymphoma developing in the pleural cavity following a long-standing history of chronic pyothorax (CP). The development of F-18 2'-deoxy-2fluoro-D-glucose (FDG) positron emission tomography combined with computed tomography (PET/CT) has contributed to the evaluation of lymphoma staging. However, only a few studies describing FDG-PET/CT findings in PAL have been published. This study reported three cases of PAL; all 3 patients had previously undergone artificial collapse therapy for pulmonary tuberculosis. Both the first case (an 84-year-old male) and second case (an 83-year-old male) complained of abdominal pain. An ultrasound scan revealed a mass shadow in the left chest wall without abnormal findings in the abdomen, and the CT and magnetic resonance imaging scans suggested malignant lymphoma of the left chest. FDG-PET/CT imaging showed extremely intense FDG uptake only in the left pleura and chest wall. Diagnosis was CP in the two patients, showing a high maximum standardized uptake value (SUVmax: early, 14.8 and delayed, 19.4 in the first case; early, 20.8 and delayed, 27.3 in the second case, respectively). Histopathological analysis of the specimens obtained by biopsy of the PET/CT-positive pleural mass showed non-Hodgkin's, diffuse large B cell lymphoma in the two cases. The third case was a 79-year-old male with relapse after right pleuropneumonectomy for PAL (diffuse large B cell lymphoma) 4 years earlier. PET/CT showed intense FDG uptake (SUVmax: early, 19.9 and delayed, 35.7) in the right pleura and chest wall. Diagnosis was CP, suggesting the recurrence of PAL. Furthermore, abnormal intense FDG uptake was noted in the hilar, mediastinal and supraclavicular lymph nodes, as well as in the spleen. In conclusion, FDG-PET/CT imaging is useful in the evaluation of the area of invasion in PAL.