Gastric carcinoid with metastasis to a regional lymph node in a dog: case report.

Gastric neuroendocrine neoplasms (NENs), historically termed gastric carcinoids, are rare in dogs and poorly characterized in veterinary medicine. A 13-year-old spayed female Maltese dog was evaluated for an incidentally detected abdominal mass. Computed tomography revealed a contrast-enhancing gastric body mass and an enlarged regional lymph node suspicious for metastasis. Surgical excision and histopathology confirmed a well-differentiated gastric NEN with regional lymph node metastasis. Immunohistochemical findings supported neuroendocrine differentiation and helped exclude major differential diagnoses. Despite relatively low mitotic activity and a relatively high proliferative index, metastatic spread was documented. This case highlights that histologically well-differentiated canine gastric NENs may exhibit malignant behavior and emphasizes the importance of thorough nodal assessment for accurate staging.