Pancreatic Colloid Carcinoma in an Elderly Cat

Area of Science:

• Veterinary Pathology
• Oncology
• Comparative Medicine

Background:

• Pancreatic tumors are uncommon in cats.
• Colloid carcinoma is a rare subtype of adenocarcinoma characterized by abundant extracellular mucin production.
• This report details a novel case in feline medicine.

Observation:

• A 21-year-old domestic shorthaired cat presented with anorexia, vomiting, and hematuria.
• Necropsy revealed a gelatinous, pale yellow mass (0.8 × 0.5 × 0.5 cm) in the left pancreatic lobe.
• Histopathology showed a non-encapsulated tumor with neoplastic columnar epithelial cells within extracellular mucin, forming tubular structures.

Findings:

• Immunohistochemistry confirmed neoplastic cells expressed cytokeratin (CK) AE1/AE3, CK7, and carcinoembryonic antigen (CEA).
• Cells were partially positive for CK19 and trypsin, and negative for vimentin.
• The tumor was diagnosed as a colloid carcinoma, the first reported instance in a cat's pancreas.

Implications:

• The cat's clinical signs were attributed to chronic renal failure, secondary renal hyperparathyroidism, and metastatic calcinosis.
• This case expands the known spectrum of pancreatic neoplasms in felines.
• Highlights the importance of considering rare tumors in feline differential diagnoses.