Rectal adenocarcinoma with rhabdoid phenotype.

Tumour of the rectum was found in 50-year old man. Two different components were identified. The rectal wall was infiltrated by a tumour with rhabdoid phenotype which formed majority of tumour mass. This type of tumour grew under differentiated tubular and mucinous adenocarcinoma which was present in small extent. Ultrastructurally rhabdoid cells revealed clusters and whorls of intermediate filaments without myoblastic differentiation. Strong anti-vimentin positivity prevailed over the anti-cytokeratin positivity. The authors suggest that this is a case of an adenocarcinoma transforming into a poorly differentiated form with rhabdoid phenotype.