Peripheral Nerve Sheath Tumor in the Upper Eyelid in a Dog

Background: Schwannomas are benign neurogenic tumours of peripheral nerves. They originate from Schwann cells, which form the neural sheath.Peripheral nerve sheath tumors most commonly found on head and neck regions both dogs people. rarely observed in ophthalmic areas. When they occur, ocular usually located orbit, uveal tract conjunctiva. The occurrence schwannoma, a subset PNST has been well documented veterinary literature. This is first report palpebral dog. lip-to-lid flap feasible technique to reconstruct upper eyelid following wide surgical removal tumor dog.Case: A 9-year-old, spayed female mixed-breed dog was referred for evaluation large mass involving right duration approximately one month. inspection revealed sero-sanguinolent discharge an oval-shaped occupying more than 70% eyelid. alert general physical examination did not abnormalities. Ocular ultrasonography show significant findings. fine-needle aspirate elucidative, even so, presumptive diagnosis neoplasia considered likely. Excision entire with 2 cm margin performed. third dorso-medial bulbar conjunctiva were also removed. Upper reconstruction performed based similar previously described cats (lip-to-lid flap). As result, neoplastic spindle cells exhibited immunoreactivity S100 intense cytoplasmic staining vimentin, supporting schwannoma. Fifteen days later, margins subdermal pattern healed skin sutures On last follow-up, 9 months post-surgery, visual, incorporated covered surface. Ten another arising inferior observed. Once ultrasound orbital invasion exenteration combined orbitectomy performed, defect auricular axial flap. Although second had same histological immunohistochemical characteristics additional Ki67 used investigate biological behavior masses.Discussion: Reported neoplasms include adenomas adenocarcinomas meibomian glands, melanomas, fibroma, fibrosarcoma, histiocytoma, mastocytoma, lipomas, papillomas, squamous cell carcinomas. To author´s knowledge, however, this case description affecting histologic distinction between PNSTs other tumors, including myxosarcoma, leiomyosarcoma, hemangiopericytoma, melanoma can be challenging requires stainin. acidic protein that identifies various nervous tissue majority canine diffusely express molecule. presented here, different adnexal structures positive vimentin all reported dogs. However, authors suggest radical surgery combining orbitectomy, miocutaneous if diagnosed eyelids caution once recurrence possible aggressive.Keywords: transposition, S100, desmin, Ki67,