Well-differentiated liposarcoma of the oesophagus: clinicopathological, immunohistochemical and array CGH analysis.

Liposarcoma develops extremely rarely in the oesophagus. Microscopically, it exhibits subtle atypia of H&E-stained features. Accordingly, immunohistochemical features and chromosomal alterations are used for its confirmatory diagnosis. However, cytogenetic analysis has not been performed for oesophageal liposarcoma. We studied chromosomal alterations using array comparative genomic hybridization (CGH), as well as endoscopic, radiological, H&E-stained and immunohistochemical features in the oesophageal well-differentiated liposarcoma of a 67-year-old man. Array CGH analysis revealed the presence of high-level amplifications at chromosomal locations 1p12-1q21.2, 12q13.2-12q15 and 12q21.33-12q23.1. At least 29 genes were highly amplified (log(2) ratio >2), among which CDK4 and MDM2 were the most highly amplified (log(2) ratio >4) and were accepted as major target genes. Moreover, the amplification of AMDHD1, HAL and LTA4H (log(2) ratio = 3.153) was a novel finding. This case suggests the presence of a characteristic profile of gene amplification in well-differentiated liposarcoma of the oesophagus. The amplified genes may be of pathogenic importance for primary oesophageal well-differentiated liposarcoma.