Apocrine gland anal sac adenocarcinoma with perineural metastasis in a cat

CASE SUMMARY: A 15-year-old female spayed domestic shorthair cat was presented for hyporexia and acute development of L4–Cd myelopathy (urinary incontinence, pelvic limb paresis with hyporeflexia and absent tail tone). Humane euthanasia was elected owing to the rapid neurological deterioration and necropsy was performed. Post-mortem examination identified a right-sided anal sac mass and medial iliac lymphadenopathy. No gross lesions were evident in the cauda equina or peripheral nerves. Histopathology and immunohistochemistry utilizing wide-spectrum cytokeratin confirmed apocrine gland carcinoma of the anal sac with lymph node, peripheral nerve and cauda equina metastasis. RELEVANCE AND NOVEL INFORMATION: This is the first report of feline anal sac adenocarcinoma metastasizing to perineural tissue. In addition, it provides a novel differential diagnosis for L4–Cd myelopathy and urinary incontinence in a cat.