Non-adherence to medical therapy in patients with end-stage kidney disease (ESKD) can lead to severe metabolic derangements rarely seen in the current medical era. Such complications may take the form of secondary hyperparathyroidism (HPT) leading to rare manifestations of bone mineral disease, and profound vitamin C deficiency from poor nutrition combined with removal of water-soluble vitamins during dialysis. Secondary HPT causes renal osteodystrophy which can lead to diffuse enlargement of the facial skeleton and morphological changes suggestive of leontiasis ossea. We report a 36-year-old, non-adherent woman on chronic dialysis for over 10 years who developed progressive, diffuse facial bone enlargement in the context of years of extreme HPT and newly diagnosed severe vitamin C deficiency. Imaging revealed diffuse hypertrophy of the maxillary and mandibular bones. Histopathology showed extensive fibro-osseous proliferation without evidence of Brown tumor, suggestive of uremic leontiasis ossea. In this report, we discuss the orofacial manifestations of secondary HPT and the possible potentiating role of vitamin C deficiency on the development of renal osteodystrophy through altered vitamin D metabolism. Non-adherent patients on chronic dialysis should be evaluated for vitamin C deficiency, and the development of uremic leontiasis ossea should be considered when such patients present with distortion of facial features in the context of severe secondary HPT.