The purpose of this paper is to present the rare occurrence of clear cell chondrosarcoma in a patient suffering from Niemann-Pick disease (NPD).

NPD is a rare autosomal recessive inborn error of metabolism. It is a lysosomal storage disorder affecting children and adolescents often causing death in early childhood although in milder form patient may survive up to adulthood. Although chondrosarcoma is a relatively common malignant bone lesion, these lesions rarely affect patients suffering from Niemann-Pick disease. This article presents the case of a 50-year-old man with a chondrosarcoma in the olecranon of the left ulna who also suffered from milder form of Niemann-Pick disease. Radiography and MRI showed cortical disruption and an expansile lesion. Histologically, the tumour was classified as grade 2 clear cell chondrosarcoma with classical differentiation according to the American Joint Committee of Cancer pathologic staging system. Amputation of an above elbow type was performed to obtain clear surgical margins. A case report and discussion of this rare association of a patient suffering from milder form of NPD who developed a clear cell chondrosarcoma is presented here. NPD and clear cell chondrosarcoma are rare diseases and together their occurrence was not found reported in the literature. NPD patients rarely live to the age of 50 years. This raises a possibility that if Niemann-Pick patients survived long enough they might develop chondrosarcoma. Alternatively this could just be coincidental. More research is needed to clarify this possibility.