Peritumoral and nodal muciphages

Area of Science:

• Pathology
• Oncology
• Cell Biology

Background:

• Muciphages are typically found in soft tissues, characterized by their vacuolated cytoplasm containing mucin.
• Their presence in lymph nodes, particularly in cancer patients, has not been previously documented.

Purpose of the Study:

• To report the novel identification and characterization of muciphages within the lymph nodes of cancer patients.
• To differentiate these muciphages from metastatic adenocarcinoma based on morphological and immunohistochemical features.

Main Methods:

• Histopathological examination of lymph node and surrounding soft tissue biopsies from three cancer patients.
• Application of mucin stains (Alcian blue, periodic acid-Schiff with diastase digestion) and enzyme digestion (hyaluronidase).
• Immunohistochemical analysis using markers for macrophages (KP-1, Mac-387) and exclusion markers (cytokeratin, S-100, leukocyte common antigen - LCA).

Main Results:

• Alcian blue positive cells with vacuolated cytoplasm, some indenting nuclei (signet-ringlike appearance), were observed in lymph node sinusoids and soft tissues.
• Immunohistochemistry confirmed these cells were positive for KP-1 and Mac-387, and negative for cytokeratin, S-100, and LCA, supporting macrophage lineage.
• Intracellular material was strongly periodic acid-Schiff positive post-diastase and Alcian blue positive, indicating epithelial-type mucin.

Conclusions:

• This study presents the first report of muciphages in regional lymph nodes of cancer patients.
• The findings highlight the importance of distinguishing muciphages from metastatic signet-ring or mucinous adenocarcinoma through careful morphological and immunohistochemical evaluation.
• Accurate identification of muciphages is crucial for correct cancer staging and patient management.