Gastric antral mucosal biopsy
All three specimens (A,B and C) are similar, showing ulcerated mucosa extensively infiltrated by small malignant cells with basophilic nuclei and high N/C ratios. The malignant cells are strongly positive with CD20 and negative for neuroendocrine markers (CD56,synaptophysin and TTF1); confirming the diagnosis of B cell lymphoma. Further immunohistochemical stains show that this is a mantle cell lymphoma.