Nonspecific pleuritis: optimal duration of follow-up.

BACKGROUND: Nonspecific pleuritis (NSP) is a frequent diagnosis after parietal pleural biopsy, but the clinical significance of this finding and need for further follow-up have not been firmly established. Previous reports suggest that 5% to 25% of patients with NSP are subsequently diagnosed with pleural malignancy. METHODS: Our pathology database was queried for patients with histologic evidence of NSP from January 01, 2001, to December 31, 2012 (n = 413). Patients with less than 1 year of follow-up after biopsy, diagnosis of empyema, tuberculous pleuritis, active systemic connective tissue disease or vasculitis, or active malignancy were excluded (n = 327). The remaining patients were included and their medical records were reviewed. RESULTS: Eighty-six patients were included. Mean follow up was 1,824 ± 1,032 days (range, 409 to 4,599 days). Three of the 86 patients with NSP (3.5%) were subsequently diagnosed with pleural malignancy. All 3 patients were found to have mesothelioma with a mean time from biopsies to diagnosis of 205 ± 126 days (range, 64 to 306 days). Twenty-two of 86 patients (25.5%) had a possible identifiable cause of pleural inflammation (benign disease). After exclusion of these 22 patients, the incidence of malignancy was 3 of 64 (4.7%). CONCLUSIONS: The incidence of subsequent pleural malignancy (mesothelioma) among patients found to have NSP based on pleural biopsy was 3.5%. Occult mesothelioma in patients with NSP will most likely be diagnosed within 1 year of the initial pleural biopsy; therefore, these patients should be followed for a minimum of 1 year to allow for timely detection of occult pleural malignancy.