Solid areas of the tumor are formed by different proportions of epidermoid (squamous) cells (red arrow), mucus cells (green arrow) and intermediate cells (yellow arrow) (histopathology, H&E stain, 10x).
The nuclear pattern of CM2B4 immunoreactivity in MCC tumor cells indicates MCPyV positivity. There is an absence of staining in the background nontumoral cells, including inflammatory, endothelial and stromal cells.
Case 1: lung; H&E staining, Fig 2A: polymorphous infiltrate in scanner view (40x). Fig 2B: lymphocytic vasculitis with infiltration of the vessel wall is seen (100x). Fig 2C: lymphocytic vasculitis with infiltration of the vessel wall is seen (200x). Fig 2D: angioinvasion by lymphoid cells in lymphomatoid granulomatosis (400x).
400x magnification image demonstrating a polymorphic lymphoid infiltrate with full maturation, ranging from small, mature lymphoid cells to intermediate to large sized immunoblastic cells. Scattered plasma cells and eosinophils are also seen.
Site: pancreatic head. Procedure: Whipple resection. Diagnosis: medullary pancreatic ductal adenocarcinoma. Histologic finding: neoplastic cells with syncytial growth and without gland formation (hematoxylin eosin, original magnification 10x). Molecular findings: microsatellite instability is very common in the case of medullary histology.