INCIDENTAL RENAL CYSTS ON CHEST CT: A RETROSPECTIVE ANALYSIS OF PREVALENCE AND IMAGING CHARACTERISTICS

Abstract

Introduction: Chest computed tomography (CT) frequently includes portions of the upper abdomen, allowing incidental visualization of renal structures. Renal cysts are among the most common incidental abdominal findings.

Purpose: To determine the prevalence, imaging characteristics, and clinical significance of incidental renal cysts detected during routine chest CT examinations.

Material and Methods: This retrospective study reviewed 1,448 consecutive adult chest CT examinations performed over a seven month period from May-November 2025. Radiology reports were screened for renal findings, and images were re-evaluated when necessary. Renal cysts were categorized using the Bosniak classification. Demographic data and cyst characteristics were recorded. Descriptive and comparative statistical analyses were conducted, and interobserver agreement was evaluated using Cohen’s kappa.

Results: Incidental renal cysts were identified in 370 patients (25.6%). The prevalence was higher in men than in women (30.6% vs 19.4%, p < 0.001). The highest number of cases were recorded in the 45–65-year age group (54.6%). Cysts were unilateral in 63.8% and bilateral in 36.2% of patients. Cortical cysts predominated (52.2%), while 11.6% were cortico-medullary. Mild hydronephrosis was found in 9.5% of patients. Most patients (55.4%) had a single cyst. Interobserver agreement was substantial (κ = 0.66). Only 2,5 % of patients had cysts requiring follow-up (Bosniak II-III).

Conclusion: Incidental renal cysts are common on chest CT and increase with age. Most are simple, unilateral, and benign. Routine reporting of incidental renal cysts is recommended to ensure appropriate follow-up when clinically warranted.