Lymph node granulomatous inflammation is a known, but fairly uncommon finding in patients with underlying malignancy undergoing endobronchial ultrasound transbronchial needle aspiration (EBUS-TBNA). Literature reports associate certain types of malignancies, such as lymphomas, testicular seminomas  and renal cell carcinomas with a higher incidence of sarcoid-like response.

We aimed to investigate the characteristics of patients with underlying malignancy that underwent EBUS-TBNA, in whom a granulomatous inflammatory response was identified prior to establishing a diagnosis of malignancy.

Out of N=891 cases from our EBUS-TBNA registry, N=168 (18.9%) of cases had a primary cytological finding of granulomatous inflammation. In N=23 (13%) cases with granulomatous inflammation, an underlying neoplasia was later found. The median (Q1-Q3) age was 62 (52-59) years and 69% of these patient were women. The most common primary underlying diseases were breast (26%) and colorectal (26%) carcinomas, followed by non-small cell lung carcinoma (13%) and then by renal (8%) and ovarian (8%) cancers. Other malignancies with an initially observed lymph node granulomatous inflammation were neuroendocrine pancreatic tumor, tonsillar squamous cell carcinoma, papillary thyroid carcinoma and Hodgkin's lymphoma. Of these 23 cases, no patient had a concomitant tuberculosis infection.

Our registry identified that in over a tenth of patients with lymph node granulomatous inflammation identified by EBUS-TBNA, a diagnosis of underlying malignancy was subsequentlly made. These findings call for further caution when differentiating granulomatous inflammation.