From the Guidelines
The most appropriate diagnostic test to perform next is thoracoscopic pleural biopsy (option D). This patient presents with concerning features suggestive of malignant pleural mesothelioma, including a history of occupational asbestos exposure (ship refitter), weight loss, night sweats, and imaging showing pleural effusion, pleural thickening, nodularity, and pleural plaques. Although the initial cytology from thoracentesis was negative for malignancy, this does not rule out mesothelioma, which often requires tissue sampling for diagnosis 1. Thoracoscopic pleural biopsy provides direct visualization of the pleural surface and allows for targeted biopsies of suspicious areas, yielding a higher diagnostic yield than closed pleural biopsy. According to a study published in the American Journal of Respiratory and Critical Care Medicine, the diagnostic yield of medical thoracoscopy was 95%, compared to 62% for pleural fluid cytology and 44% for closed pleural biopsy 1.
The European Respiratory Society and the European Society of Thoracic Surgeons guidelines also recommend thoracoscopy as the best method to obtain a diagnosis of malignant pleural mesothelioma, except in cases of pre-operative contraindication or pleural symphysis (grade 1A) 1. This approach is superior to repeat thoracentesis, which is unlikely to provide additional information given the already negative cytology. While PET scanning might help identify metabolically active areas, it cannot provide a definitive diagnosis without tissue confirmation, and its use is not recommended for the diagnosis of mesothelioma (grade 1C) 1. Given the high clinical suspicion for mesothelioma in this patient with occupational exposure and concerning symptoms, obtaining adequate tissue samples through thoracoscopy is the most appropriate next step for establishing a diagnosis.
Some key points to consider in this case include:
- The patient's history of occupational asbestos exposure, which increases the risk of malignant pleural mesothelioma
- The presence of weight loss, night sweats, and imaging findings suggestive of pleural effusion, pleural thickening, nodularity, and pleural plaques
- The negative initial cytology from thoracentesis, which does not rule out mesothelioma
- The higher diagnostic yield of thoracoscopic pleural biopsy compared to closed pleural biopsy and pleural fluid cytology
- The recommendation of thoracoscopy as the best method to obtain a diagnosis of malignant pleural mesothelioma by the European Respiratory Society and the European Society of Thoracic Surgeons guidelines.
From the Research
Diagnostic Approach
The patient's symptoms and test results suggest a possible diagnosis of malignant pleural mesothelioma (MPM). The most appropriate diagnostic test to perform next would be:
- Thoracoscopic pleural biopsy (D): This procedure allows for complete visualization of the pleural cavity and provides high-quality biopsy samples, which is essential for diagnosing MPM 2, 3, 4.
Rationale
The patient's history of asbestos exposure as a retired ship refitter, combined with the presence of pleural plaques and a large pleural effusion, increases the suspicion of MPM. The cytology findings were negative for malignancy, but this does not rule out MPM. Thoracoscopic pleural biopsy is a minimally invasive procedure that can provide a definitive diagnosis and guide further treatment.
Comparison of Diagnostic Tests
The other options are less suitable for the following reasons:
- Closed pleural biopsy (A): This procedure may not provide sufficient tissue for diagnosis, especially in cases where the pleura is thickened or nodular 2.
- Fluorodeoxyglucose PET (B): While PET scans can help identify areas of increased metabolic activity, they are not specific for MPM and may not provide a definitive diagnosis 3.
- Repeat thoracentesis (C): Repeating the thoracentesis may not yield additional diagnostic information, especially if the initial cytology results were negative for malignancy 5.