Intranuclear inclusions in a dog with B-cell leukemia

Area of Science:

• Veterinary Medicine
• Canine Oncology
• Hematopathology

Background:

• Acute B-cell leukemia is a rare hematologic malignancy in dogs.
• Diagnosis often relies on bone marrow cytology and immunophenotyping.
• Intranuclear inclusions are uncommon findings in canine leukemia.

Observation:

• A 7-year-old Shetland Sheepdog presented with anorexia, thrombocytopenia, and neutropenia.
• Bone marrow cytology revealed a high percentage of anaplastic large mononuclear cells of B-cell origin.
• Microscopic examination identified intranuclear inclusions within neoplastic cells, resembling Dutcher bodies.

Findings:

• Immunohistochemistry and flow cytometry confirmed B-cell origin and IgG immunopositivity of intranuclear inclusions.
• The periodic acid-Schiff reaction was negative, ruling out polysaccharide accumulation.
• The dog achieved remission with chemotherapy but succumbed to tumor progression and renal insufficiency.

Implications:

• This case represents the first documented instance of canine acute B-cell leukemia with Dutcher body-like intranuclear inclusions.
• The findings expand the understanding of cytologic variations in canine B-cell leukemia.
• Further research may elucidate the pathogenesis and clinical significance of these inclusions in canine hematologic malignancies.