Cryogenic insulated cylinders are extensively used for the storage and transportation of liquefied gases in industrial, medical, and aerospace applications. Among their structural components, the neck tube plays a critical role by providing mechanical support while simultaneously limiting heat leakage between the inner and outer vessels. Due to severe temperature gradients and complex loading conditions, the neck tube region is highly prone to thermal stress concentration and structural degradation. This review paper presents a comprehensive assessment of existing research on thermal stress analysis, heat transfer characteristics, and structural behavior of neck tubes in vertical cryogenic insulated cylinders, with a particular focus on finite element–based studies using ANSYS software. Previous numerical and experimental investigations related to temperature distribution, heat leakage, stress concentration, material behavior at cryogenic temperatures, and reinforcement techniques are systematically discussed. The review highlights the influence of geometric parameters, material properties, and loading conditions on neck tube performance. The findings summarized in this paper aim to provide useful design insights and identify research gaps for improving the safety, efficiency, and reliability of cryogenic storage systems.