Cutaneous plasmacytomas in dogs: a morphologic and immunohistochemical study.

Area of Science:

• Veterinary Pathology
• Dermatology
• Oncology

Background:

• Cutaneous plasmacytomas are observed in dogs, but their benign nature and diagnostic markers require further elucidation.
• Understanding the characteristics of canine cutaneous plasmacytomas is crucial for accurate diagnosis and treatment.
• Previous studies have focused on various skin tumors, necessitating specific research on plasmacytomas.

Purpose of the Study:

• To characterize canine cutaneous plasmacytomas based on morphology and immunohistochemistry.
• To evaluate the efficacy of surgical excision for treating these tumors.
• To establish canine cutaneous plasmacytomas as a distinct entity in the differential diagnosis of canine cutaneous round cell tumors.

Main Methods:

• Histopathological examination of 49 cutaneous plasmacytomas from 46 dogs.
• Immunohistochemical analysis using markers including cytokeratins, canine IgG F(ab)2, neurofilament, neuron-specific enolase, S-100 protein, and vimentin.
• Correlation of immunoreactivity with tumor grade and assessment of treatment outcomes following surgical excision.

Main Results:

• Tumors were solitary, predominantly affecting middle-aged to old dogs, with common locations including digits, lips, and ears.
• Immunoreactivity was primarily observed with antibodies against canine IgG F(ab)2 and vimentin, with vimentin showing stronger expression.
• No correlation was found between immunoreactivity and the histologic grade of the tumors.
• Surgical excision resulted in a high cure rate (92.3%) in the 39 dogs with follow-up data.

Conclusions:

• Canine cutaneous plasmacytomas are benign neoplasms.
• Immunohistochemistry, particularly vimentin expression, aids in characterization but does not correlate with tumor grade.
• Surgical treatment is highly effective, supporting their inclusion in the differential diagnosis of canine cutaneous round cell tumors.