Cutaneous histiocytosis in dogs

Area of Science:

• Veterinary Dermatology
• Canine Pathology
• Histiocytic Disorders

Background:

• Canine cutaneous histiocytoma is a common benign skin tumor.
• Multifocal presentations of histiocytic lesions are less common and require characterization.

Purpose of the Study:

• To describe the clinical and histological features of multifocal cutaneous histiocytic lesions in dogs.
• To differentiate these lesions from other skin conditions.

Main Methods:

• Clinical case review of 9 dogs with multifocal skin lesions.
• Histopathological examination of skin biopsies.
• Electron microscopy to characterize cellular morphology.

Main Results:

• Nine dogs presented with multiple erythematous skin plaques/nodules (1-5 cm).
• Histology revealed dermal/pannicular infiltrates of large histiocytic cells with mixed inflammatory cells.
• Electron microscopy showed cells similar to canine cutaneous histiocytoma.
• Lesions exhibited waxing/waning behavior and new lesion formation despite treatment.
• No infectious agent was identified.

Conclusions:

• Multifocal cutaneous histiocytic lesions represent a distinct clinical entity in dogs.
• The cellular morphology suggests a histiocytic origin, possibly related to cutaneous histiocytoma.
• The recurrent and self-limiting nature of the lesions warrants further investigation into their etiology.