Seven Years of 700 Cholesterol Without Coronary Atherosclerosis: A Lean Mass Hyper-Responder Case Report

Background: While reducing LDL cholesterol (LDL-C) remains central focuses of conventional preventive cardiology, substantial heterogeneity exists in the cardiovascular risk associated with even extreme LDL-C elevations, likely depending heavily on the broader metabolic context. Specifically, the lean mass hyper-responder (LMHR) phenotype—characterized by markedly elevated LDL-C with elevated high-density lipoprotein cholesterol (HDL-C) and low triglycerides in the setting of a ketogenic diet—has recently been described, though its long-term risk profile remains poorly defined. Case Presentation: We describe a male in his 30s without any congenital dyslipidemia who adopted a ketogenic diet for the management of ulcerative colitis and who subsequently exhibited a sixfold increase in LDL-C from a baseline of 95 mg/dL to 574 mg/dL, with total cholesterol of up to 705 mg/dL, HDL-C at 124 mg/dL, and triglycerides at 34 mg/dL. Despite maintaining these extreme lipid levels for nearly seven years, he demonstrated no coronary plaque or stenosis on coronary computed tomography angiography (CCTA; CAD-RADS = 0). Additionally, quantification of coronary plaque as assessed by AI-guided quantified analysis by Heartflow® identified 0 mm3 plaque in any vessels, placing him in the lowest percentile for atherosclerotic plaque. Conclusions: This case represents an extreme and extensively characterized example of the LMHR phenotype and highlights the limitations of extrapolating cardiovascular risk from LDL-C levels alone without consideration of broader patient context and the etiology of hypercholesterolemia. While a single case cannot redefine clinical practice, this well-characterized case is consistent with emergent literature on LMHR, and careful study of such individuals may provide valuable insights into lipid metabolism, atherosclerosis biology, and precision cardiovascular risk assessment.