# Anatomic Distribution and Clinical Presentation of Pulmonary Carcinoids: A Single-institutional Study

## TL;DR

This study finds that lung carcinoid tumors are now often found incidentally in peripheral areas, likely due to increased imaging use.

## Contribution

The study provides contemporary data showing a shift in the anatomic distribution and detection pattern of pulmonary carcinoid tumors.

## Key findings

- Most PCTs were detected incidentally and located peripherally in the lung.
- The likelihood of PCTs being peripheral and asymptomatic increased over the study period.
- PCTs are now more commonly found incidentally on imaging rather than causing obstructive symptoms.

## Abstract

Pulmonary carcinoid tumors (PCTs) have historically manifested predominantly as central lung lesions causing postobstructive symptoms. However, nearly all case series of PCTs to date evaluate cohorts in years before 2010. Because an increased volume of cross-sectional imaging studies results in more frequent detection of incidental lung nodules, we sought to evaluate whether the nature of this cancer’s clinical characteristics may be evolving by studying a contemporary series of patients.

The study analyzed all patients with a diagnosis of PCT at Thomas Jefferson University Hospital (Philadelphia, PA) between 2006 and 2020. The study evaluated tumor location within the bronchial tree (ie, central or peripheral), the presence or absence of symptoms at diagnosis, patient demographics, and nodule characteristics on computed tomography.

A total of 73 PCTs were analyzed in 72 patients. Most PCTs were detected incidentally (48 of 72; 95% CI: 55%-77%) and located peripherally (41 of 67; 95% CI: 49%-73%). Logistic regression analysis demonstrated that the likelihood of PCTs having these features increased over the study period.

PCTs manifested predominantly as peripheral lung lesions detected incidentally on computed tomography, which contrasts with the existing literature. This may reflect the changing nature of PCT diagnosis as cross-sectional imaging volume has increased. Clinicians should be mindful that incidental solitary pulmonary nodules detected on chest imaging may represent PCT, especially if the lesions are slow growing.