Peritoneal lymphomatosis with pleural and peritoneal effusions in a dog: a case report

Peritoneal lymphomatosis (PL) is a rare lymphoid neoplasm in dogs. A nine-year-old spayed female Labrador retriever presented with pleural and peritoneal effusions. Diagnostic imaging revealed diffuse nodular to massive lesions in the mesentery, particularly in the caudal abdomen. While the superficial lymph nodes did not show significant changes, enlargement was observed in the intra-abdominal and intra-thoracic lymph nodes. Cytological and flow cytometric analyses of the effusion indicated the presence of large B-cell lymphocytes expressing CD3-/CD5-/CD14-/CD21-/CD34+/CD45+/CD79a+. PL was diagnosed using diagnostic imaging and fluid analysis. This case report highlights the clinical and diagnostic features of canine PL.