Subcutaneous Cervical Mass in the Northern Tree Shrew (Tupaia belangeri)

HistoryAn 8-year-old, 260-g, singly housed, experimentally naive, female northern tree shrew (Tupaia belangeri) housed at the University of Pennsylvania presented to the veterinary team with a 5-day history of a fast-growing cervical mass.The patient had a body condition of 4.5 on a scale of 1 (emaciated) to 5 (obese), with normal appetite, water intake, fecal output, and activity level.The mass had reportedly increased in size by 25% within 1 week of its initial observation.The tree shrew originally arrived at the University of Pennsylvania in 2017 from the Max Planck Florida Institute for Neuroscience (Jupiter, FL) and had regularly received routine cage-side health assessments.Due to her high body condition score, she had been maintained on a low glycemic diet for weight control since 2022.Twelve other tree shrews living in separate enclosures within the same vivarium and were reported to be healthy.The tree shrew was hand-caught for an awake examination.Physical examination revealed a 1.5 × 1.5 × 1.5-cm, tan to pink, round, soft, freely moveable subcutaneous mass with 2 pinpoint black foci located at the caudoventral aspect of the right mandible.Examination otherwise revealed normal vital signs and no other abnormalities.