Case: AP146
Contributor's Comment: This is the peritoneal biopsy of the mesothelioma previously put up as AP135 (cytology case). The malignant cells are positive for calretinin, cytokeratin and vimentin but not for CEA, Leu M1, BerEP4, S-100 protein, HMB 45, actin, desmin, heppar 1, CD 45 and ALK-1, hence confirming their mesothelial nature.

Most participants score full marks, except 246 and 663 whose comments are not specific enough.