대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Pyothorax Associated Lymphoma (PAL)

Radiologic Findings

Plain chest radiograph that was taken 2 years ago shows large mass-like lesion in the right hemithorax. This lesion has a wall calcification. CT taken at that time shows this is chronic empyema with wall calcifications (not shown). On plain chest radiogragh taken at admission, we can identify that the supero-medial portion of the empyema grows, and the wall calcification shifts downward and laterally by the newly occurring opacity. On CT image taken at admission, soft tissue mass occurs in the superomedial portion of the chronic empyema. This mass manifests itself as heterogenous attenuation.

Brief Review

Pyothorax-associated lymphoma (PAL) is a distinctive type of malignant lymphoma of mostly B-cell nature, strongly associated with EBV infection. PAL develops in the pleural cavity after a long-standing history of pyothorax. According to Nakatsuka et al’s study, 80% of the patients have a history of pyothorax resulting from artificial pneumothorax for treatment of pulmonary tuberculosis, and 17% of the patients have a tuberculous pleuritis.

Chest and/or back pain are the most common presenting symptoms, which are not features of chronic pyothorax. CT is recommended for follow-up of patients with chronic pyothorax and PAL, because mass can be detected in 85% of patients by CT. However, soft-tissue masses in chronic pyothorax may correspond to several disease processes. Acute reactivation of tuberculosis is one possibility, and other pathogen such as aspergillosis or microorganisms can cause superimposing infection. Neoplasms other than lymphoma, such as mesothelioma, squamous cell carcinoma, and soft-tissue sarcoma, have been associated with chronic tuberculous empyema. It is difficult to differentiate PAL from these other diseases by means of imaging alone, biopsy is needed to confirm the diagnosis. Percutaneous core biopsy is the simplest way of obtaining samples of tumors.

The symptom/sign and radiographic findings in PAL patients often suggest a diagnosis of lung cancer, especially small cell lung cancer. Moreover, the serum levels of NSE are occasionally elevated in PAL patients, which suggest the diagnosis of small cell lung cancer. The NSE levels in PAL decrease after chemotherapy in most cases; thus, the serum NSE levels can be a useful marker for monitoring the disease activity of PAL.

PAL usually shows a response to chemotherapy and radiotherapy. However, the overall prognosis is poor, with a 5-year survival of 21.6%. Those of patients who showed complete response to chemotherapy and/or radiotherapy were better (5-year survival of 49.0%).

References

1. Nakatsuka S, Yao M, Hoshida Y, Yamamoto S, Iuchi K, Aozasa K. Pyothorax-associated lymphoma: a review of 106 cases. J Clin Oncol 2002; 15; 20:4255-4260.

2. Brun V, Revel MP, Danel C, Fournier LS, Souilamas R, Frija G. Case report. Pyothorax-associated lymphoma: Diagnosis at percutaneous core biopsy with CT guidance. AJR Am J Roentgenol 2003; 180:969-971.

3. Jeung MY, Gangi A, Gasser B, et al. Imaging of chest wall disorders. RadioGraphics 1999; 19:617 ?637.

Keywords

Pleura, Lymphproliferative disorder, Lymphoma,