The concurrence of lung malignancies and organizing pneumonia

SESSION TITLE: Lung Cancer Posters 6 SESSION TYPE: Original Investigation Posters PRESENTED ON: 10/11/2023 12:00 pm - 12:45 pm PURPOSE: Nearly 240,000 individuals were diagnosed with lung cancer in 2022 through countless tissue sampling procedures. Along with the advent of increasingly sophisticated interventional bronchoscopy tools, there is increasing comfort and utilization of non-surgical lung biopsies for pulmonary nodule diagnoses. Organizing pneumonia (OP) is considered a benign histologic finding during tissue analysis. However, secondary OPs can be incited by other factors, including the presence of an underlying lung malignancy. The diagnosis of a secondary OP by bronchoscopic biopsy may lead to a missed or delayed diagnosis of lung malignancy. We hope to provide a sense of diagnostic accuracy and management guidance for the finding of OP on lung tissue samples from pulmonary nodules. METHODS: Through an IRB-exempt protocol, we accessed Indiana University Health’s patient data from 1/1/2010 to 1/1/2023 for patients with concurrent OP and primary or metastatic lung malignancies using a word search for “organizing”, “pneumonia” and “carcinoma”. 70 charts were reviewed and 13 subjects were excluded who did not accurately meet the criteria of having both carcinoma and OP. We collected age, race, specimen type, final histology/pathology, other benign pathologies (i.e. granulomas), location of OP relative to their primary tumor, tumor size (surgical pathology and/or CT as available), stage, time to death from pathologic diagnosis and findings on preceding tissue samplings procedures. RESULTS: 57 individuals were found to have concurrent lung cancer and OP on histopathology. 51.0% were female, 66.7% were white individuals, and the median age was 66.0. 87.7% of our samples were from surgical resections, while 3.5% were from core biopsies, 5.3% from transbronchial biopsies, 3.5% from fine needle aspirations and 1.8% from rigid bronchoscopy samples. The most common concurrent lung malignancies were primary non-small cell lung cancers (NSCLCs) with 36.8% lung adenocarcinomas and 45.6% squamous cell carcinomas. No incidents of small cell lung cancers with OP were found in our cohort. In 82.4% of cases the concurrent OP was described in the same lobe as their lung malignancy. CONCLUSIONS: OP is more often observed concurrently with NSCLCs than other malignancies and typically is described in the same lobe. Both lung adenocarcinoma and squamous cell histologies were associated with concurrent OP, with the latter being more prevalent than what would be expected based on typical NSCLC histologic distribution. CLINICAL IMPLICATIONS: Caution should be maintained in attributing benignity to tissue biopsies yielding OP; concurrent lung cancer should be considered in those in whom there is a high degree of clinical suspicion for lung cancer. DISCLOSURES: No relevant relationships by Nawar Al Nasrallah No relevant relationships by Ahmed Alomari No relevant relationships by Catherine Sears No relevant relationships by Srikanth Vedachalam