Peritumoral and nodal muciphages.

Three patients who underwent surgery for cancer showed Alcian blue positive cells in the sinusoids of the regional lymph nodes and, in one case, extensive infiltration in the soft tissues around the tumor. The cells contained variably sized vacuoles that occasionally indented the nuclei, imparting a signet-ringlike appearance. They were interpreted as muciphages based on morphology, reactivity with mucin stains, positive immunohistochemical staining for KP-1 and Mac-387, and negative staining for cytokeratin, S-100, and leukocyte common antigen (LCA). The material contained in these cells was Alcian blue positive at pH 2.5 and pH 1, and was strongly periodic acid-Schiff positive after diastase digestion. Hyaluronidase only slightly reduced the intensity of the Alcian blue stain. These results indicate that the bulk of the material was epithelial-type mucin. To our knowledge, this is the first report of muciphages in lymph nodes. Careful attention to morphology and immunohistochemical findings is necessary to avoid confusion with metastatic or infiltrating signet ring or mucinous adenocarcinoma.