Metastatic Mammary Adenocarcinoma in a Sugar Glider (Petaurus breviceps)

A 9-year-old, intact female sugar glider (Petaurus breviceps) housed at a zoological institution developed a metastatic mammary adenocarcinoma. The tumor progressed over the course of approximately 7 months from an initial small mass within the pouch that was cytologically identified as a mammary cyst to a large, multilobulated mass with both local and distant metastases. At the time of euthanasia, the patient presented with unilateral pelvic limb paralysis; necropsy revealed it to be the result of metastatic sublumbar lymphadenomegaly and subsequent direct damage to lumbar vertebrae with compression of the associated spinal nerves. Additionally, the metastatic sublumbar mass enveloped the right ureter and caused a secondary hydronephrosis. Additional sites of metastasis included a pouch lymph node, axillary lymph nodes, and lung. Based on the lack of published information, metastatic mammary adenocarcinoma appears to be an uncommon disease presentation in sugar gliders.