The aim of our study was to investigate the correlation between volumes of thoracic fat distributed in different compartments and geometry of vulnerable coronary plaques assessed by coronary computed tomography angiography (CCTA), in patients with acute chest pain. Methods: This was a non-randomized, observational, single-center study, including 50 patients who presented in the emergency department with acute chest pain who underwent 128-slice single-source CCTA. Plaque geometry was evaluated in transversal and longitudinal planes, and the assessment of adipose tissue was performed using the Syngo.via Frontier (Siemens AG, Healthcare Sector, Forchheim, Germany) research platform. Results: Eccentric plaques presented a significantly higher incidence of spotty calcification (40% vs. 22%, p = 0.018), whereas positive remodeling, volume of low attenuation plaque, and incidence of napkin-ring sign were not significantly different between the study groups or in ascending versus descending plaques. The volume of pericoronary fat around the plaque was significantly larger near eccentric lesions (707.68 ± 454.08 mm3 vs. 483.25 ± 306.98 mm3, p = 0.046) and descendent plaques (778.26 ± 479.37 mm3 vs. 473.60 ± 285.27 mm3, p = 0.016). Compared to ascending lesions, descendent ones presented a significantly larger volume of thoracic fat (1,599.25 ± 589.12 mL vs. 1,240.71 ± 291.50 mL), while there was no significant correlation between thoracic fat and cross-sectional eccentricity. Conclusions: The phenotype of plaque distribution and geometry seems to be associated with a higher vulnerability of coronary lesions and may be influenced by the local accumulation of inflammatory mediators released by the pericoronary epicardial adipose tissue.