Apocrine Gland Anal Sac Adenocarcinoma in Dogs: 22 Cases (2015-2020)

Abstract

Background: Apocrine gland anal sac adenocarcinoma (AGASACA) is a highly malignant disease mostly invading regional lymph nodes at the time of disease diagnosis. Methods: Twenty- two cases of Apocrine gland anal sac adenocarcinoma (AGASACA) were treated during five years. Contrast radiography with Iohexol and Lipidol were carried out to detect primary anal sac mass and regional lymph node through indirect lymphography technique. For clinical staging, ultrasonography, fine-needle aspiration cytology, histopathology of both primary tumor mass and regional lymph node were performed. Closed anal Sacculectomy was performed as curative therapy for anal sac adenocarcinoma. Result: The median age and weight of dogs at presentation were 8.4 years and 20.9 kg, respectively. Diagnostic radiology, histopathology and biochemical assay confirm twenty-two cases of anal sac adenocarcinoma and medial iliac lymph node to be sentinel lymph node. Carcinoma was of unilateral occurrence in all the dogs. Four (18%) dogs had hypercalcemia and twelve (54%) had metastases to the regional lymph nodes with clinical signs of tenesmus or constipation, polyuria -polydipsia and anorexia. Apocrine gland Adenocarcinoma of anal sac was found to initially metastasize to the medial iliac lymph node. Survival times of dogs treated with the surgical procedure only (8 out of 22 dogs) were appreciably longer than the dogs with therapeutic only. Animals with metastasis to regional lymph nodes or lymphadenopathy had poor prognosis.