Non-specific pleuritis in patients with active malignancy

Background and objective: Pleuroscopy is the test of choice for patients with suspected malignant pleural effusion and negative cytology. Biopsies negative for malignancy are frequently attributed to non-specific pleuritis, which poses a dilemma in patients with a known active malignancy, raising concern for a false-negative result. Our primary objective was to determine the outcomes of patients with active malignancy who had a non-malignant diagnosis on pleuroscopy. Methods: Retrospective review of all pleuroscopy cases from January 2005 to January 2015 at our institution was conducted. Biopsies were categorized by histopathology as malignant, eosinophilic or non-specific pleuritis. Malignant histopathology was considered a true positive. Eosinophilic or non-specific pleuritis was categorized as malignant, if malignancy was later identified during follow-up, or chemotherapy induced, possible radiation induced, other paramalignant, other benign or idiopathic. Results: Of the 199 pleuroscopy cases reviewed, 172 (86%) had a history of active malignancy. On histopathology, 73 (42%) had malignancy, 9 (5%) had eosinophilic pleuritis and 90 (52%) had non-specific pleuritis. Three patients with non-specific pleuritis were diagnosed with malignancy at follow-up. Pleuritis in 24 patients was chemotherapy induced, 27 were possibly radiation induced, 11 were other paramalignant and 3 were other benign. Idiopathic pleuritis was diagnosed in 31 patients. Patients were monitored for a mean of 23 ± 11 months. Conclusion: The prevalence of malignant pleural disease was lower than expected for our patient population. Patients with no malignancy on histopathology were most likely to have non-specific pleuritis, a cause for which was identified in a majority of patients after clinical review.