A 17-year-old spayed female Shih Tzu dog, weighing 5.0 kg, presented with frequent coughing and respiratory distress. Blood tests revealed mild thrombocytosis, and thoracic ultrasonography and radiography confirmed a significant amount of pleural effusion. However, the thoracic radiographs showed no radiopaque nodules or interstitial patterns indicative of thoracic tumors. Thoracentesis was performed to relieve effusion-induced thoracic pressure, yielding a hemorrhagic serosanguinous pleural fluid. The cytological analysis of this fluid revealed mesothelial cells, supporting the clinical diagnosis of mesothelioma in situ. To address the patient’s clinical symptoms, an aggressive management approach was implemented with chest tube placement to address recurrent pleural effusion after initial thoracentesis. During treatment, the patient exhibited stable health and adapted well to daily life. To the best of our knowledge, this is the first reported case of mesothelioma in situ with hemorrhagic malignant pleural effusion in South Korea. Using a chest tube as an aggressive treatment successfully alleviated dyspnea symptoms and provided symptomatic relief in a patient with mesothelioma in situ.

Malignant pleural effusion (MPE) and blood samples can be used as a practical source for detection of epidermal growth factor receptor (EGFR) mutations in patients with advanced non-small cell lung cancer. We compared EGFR mutation status of cell blocks, cell-free fluid of MPE, and plasma from patients with lung adenocarcinoma. We obtained paired samples of MPE and plasma from 14 pathologically-confirmed lung adenocarcinoma patients. Peptide nucleic acid (PNA)-mediated real-time polymerase chain reaction (RT-PCR) clamping was performed for determination of EGFR mutation status. EGFR mutations were detected in five (35.7%) cell blocks of MPE, which showed results identical to those of the corresponding cell-free fluid, whereas mutations were detected in the plasma of only two (40.0%) of the five patients. Of seven patients treated with EGFR tyrosine kinase inhibitors (TKIs), EGFR mutations were detected in cell blocks, cell-free fluid of MPE, and plasma for only one of the four patients who responded to EGFR TKIs, while mutations were detected only in cell blocks of MPE and cell-free fluid of the three remaining patients. Our results suggest that detection of EGFR mutations in cell-free pleural fluid from lung adenocarcinoma patients using highly sensitive methods may be feasible, but that analysis of free plasma may lead to undetected mutations and misdiagnosis.

A paradoxical response in tuberculosis is defined as clinical and radiological worsening of previous lesions or development of new lesions after initial improvement during the process of anti-tuberculous treatment. The authors report on a patient who developed massive pleural effusion as a paradoxical response after 8 weeks of anti-tuberculous treatment. The patient’s symptoms were improved with thoracostomy without any change of anti-tuberculous medications. If symptoms worsen during the process of anti-tuberculous treatment, drug resistance, non-compliance, or other diseases should be excluded first. If it is regarded as a paradoxical response, the treatment plan need not be changed except for additional conservative treatment.