AIM: An inherited deficiency of human lysosomal acid lipase (LAL) results in the rare conditions of Wolman disease and cholesteryl ester storage disease (CESD). We want to present the rare case of CESD in an adult. METHODS: We report about an adult female patient with severe chronic diarrhea and weight loss as a consequence of CESD. Clinical examination revealed signs of malabsorption and slightly elevated liver enzymes. RESULTS: Histopathologic changes in the liver tissue and DNA sequence analysis confirmed the diagnosis of CESD due to homozygosity for the most common CESD mutation, a G934A splice site defect encoded by exon 8 of the lysosomal acid lipase (LIPA) gene. CONCLUSION: It is the first case in the literature with diarrhea as a putative symptom of CESD in adult patients. AIM: An inherited deficiency of human lysosomal acid lipase (LAL) results in the rare conditions of Wolman disease and cholesteryl ester storage disease (CESD). We want to present the rare case of CESD in an adult. METHODS: We report about an adult Female patient with severe chronic diarrhea and weight loss as a consequence of CESD. Clinical examination revealed signs of malabsorption and slightly elevated liver enzymes. RESULTS: Histopathologic changes in the liver tissue and DNA sequence analysis confirmed the diagnosis of CESD due to homozygosity for the most common CESD mutation, a G934A splice site defect encoded by exon 8 of the lysosomal acid lipase (LIPA) gene. CONCLUSION: It is the first case in the literature with diarrhea as a putative symptom of CESD in adult patients.