Medusa Head Aspect of the Thoracic Duct in <scp>CCLA</scp> Patients: Anatomical Variation or Pathological Marker? A Multicenter Case–Control Study

Central conducting lymphatic anomaly (CCLA) is a rare condition characterized by central lymphatic dysfunction and lacking diagnostic criteria. In clinical practice, we observed a distinct imaging feature in CCLA patients: a plexiform configuration of the thoracic duct, described as the "Medusa head" pattern. This study aimed to determine whether this pattern is associated with CCLA. We conducted a retrospective multicenter case-control study including 31 CCLA patients and 103 healthy controls who underwent magnetic resonance imaging. Imaging findings were reviewed to assess thoracic duct anatomy, including the presence of the "Medusa head" pattern. This pattern was identified in 81% of CCLA patients compared to only 1.2% of controls, with a strong association with CCLA (odds ratio 337.5, 95% CI: 38.8-2938.2; p < 0.001). Our findings suggest that the "Medusa head" configuration of the thoracic duct is not merely an anatomical variant but rather a pathological marker of CCLA. This feature, highly specific but not universal, could help refine diagnostic criteria and guide management of CCLA. Further studies are needed to explore its role in diagnostic algorithms and future classification systems.