Non-nodule-forming malignant lymphoma developing in the wall of chronic pyothorax: a case report

We report a case of non-nodule-forming malignant lymphoma developing in the pyothoracic wall following artificial pneumothorax. A 69-year-old man, who had undergone an artificial pneumothorax for pulmonary tuberculosis 48 years earlier, was admitted to our hospital for left chest pain. The chest radiograph and CT scan showed a thickened and calcified pyothoracic wall, but no definite tumor mass was revealed in the wall. Pulmonary decortication was performed. Although no discrete tumor tissue was found macroscopically surround the resect ed pyothoracic wall, histological examination revealed that anaplastic large cell lymphoma cells proliferated diffusely in the pyothoracic wall. Immunohistochemical examination of the tumor cells indicated null cell characteristics. Epstein-Barr virus mRNA was found in the tumor tissue specimens by in situ hybridization. Considering that according to previously reported cases of pyothorax-associated lymphoma, the most common presenting symptoms were unrelenting chest pain and a rapidly growing mass, the present case showed a rare growth pattern. Malignant lymphoma should be considered when there is chronic empyema following artificial pneumothorax even if nodular growth was not found in radiological examinations.