Hyalinosis cutis et mucosae (lipoid proteinosis, Urbach-Wiethe disease) is a rare syndrome with autosomal recessive inheritance. The disease is characterized by diffuse deposition of a hyalinelike substance in the dermis, submucosal connective tissue, and various internal organs. In this study, the patient demonstrated classic signs and symptoms of lipoid proteinosis except for gingival infiltration. Gingival infiltration is still an unexplainable feature of this disease. In the context of this case, the diagnostic significance of the microscopic findings of the gingival tissues and the possible factors playing a role in gingival hypertrophy, are discussed.