Clear Cell Chondrosarcoma in Association With Niemann-Pick Disease

Purpose: The purpose of this case report is to bring to light this unusual combination of two rare diseases, namely Neimann-Pick disease Type B and clear cell chondrosarcoma occurring in the same patient. This has not previously been reported in the world literature. Subject: Niemann-Pick disease (NPD) is a rare autosomal recessive inborn error of metabolism. Type B NPD is even rarer. It is a lysosomal storage disorder affecting children and adolescents often causing death in early childhood, although in milder form patients may survive up to adulthood, like our patient. Clear cell chondrosarcoma is a very rare type of chondrosarcoma affecting the epiphyseo-metaphyseal region of long bones. We present a patient suffering from a milder form of Neimann Pick disease who developed a clear cell chondrosarcoma. We investigated to find if there was likely to be any relationship between these two events. Results: NPD type B is caused by a three-base deletion in chromosome 11. Chondrosarcoma and multiple exostoses occur due to loss of tumour suppressor gene EXT 2 from centromeric region on chromosome 11, though it is difficult to establish the link between the two, as the two together have not yet been reported in the literature. NPD may present diagnostic difficulties when it occurs with chondrosarcoma. Discussion: We conclude that the two diseases have not been reported together in the world literature and there is some evidence to show that chromosome 11 is central to both diseases. More research is needed to see if one leads to the other.