Cutaneous Histiocytic Sarcoma with Regional Lymph Node Metastasis in a Netherland Dwarf Rabbit (Oryctolagus...

Area of Science:

• Veterinary Pathology
• Oncology
• Comparative Pathology

Background:

• Cutaneous histiocytic sarcoma is a rare malignancy affecting various species.
• Lagomorphs, such as rabbits, are not commonly reported to develop this type of tumor.
• Early diagnosis and understanding of tumor behavior are crucial for effective management.

Observation:

• A 10-year-old Netherland dwarf rabbit presented with a lip mass characterized by ulceration and hair loss.
• Cytological and histological examinations revealed atypical, pleomorphic neoplastic cells, often multinucleated.
• Immunohistochemical analysis showed positivity for Iba1 and vimentin, with a high proliferation index (Ki67 ~41%).

Findings:

• The mass was diagnosed as cutaneous histiocytic sarcoma based on integrated clinical, histopathological, and immunohistochemical data.
• Metastasis to the cervical lymph nodes was confirmed six months post-excision, indicating aggressive tumor behavior.
• This represents the first documented case of cutaneous histiocytic sarcoma in lagomorphs.

Implications:

• This case expands the known spectrum of neoplastic diseases in rabbits.
• It underscores the importance of considering histiocytic sarcoma in rabbits with cutaneous masses.
• Further research into the pathogenesis and treatment of this condition in lagomorphs is warranted.