Multicentric Squamous Cell Tumors in Panther Chameleons (Furcifer pardalis)

Squamous cell carcinoma is one of the most common malignant epithelial tumors in dogs and cats and shows also a high incidence in human population. Chemical and physical carcinogens as well as viral infections have been shown to predispose epithelial cells to genetic cell damage, leading to formation of neoplastic precursor cells or promoting tumor proliferation. A number of herpetological cases are documented in literature, most of these being solitary tumors with rare tendency of metastasis. Our study describes 7 cases of multicentric epidermal squamous cell tumors in male panther chameleons (Furcifer pardalis). Two of these cases, which were examined by necropsy with the owners’ consent, showed distant metastasis into the lungs. In order to elucidate the etiology of these cases the submitted tissues were scanned by transmission electron microscopy for the detection of viral particles. No viral particles were visible ultrastructurally. Pan-papilloma-, irido-, rana-, adeno- and herpesvirus-PCRs (polymerase chain reaction) were performed on all of the tissues but could not demonstrate corresponding virus-specific sequences. Universal PCRs for para- and orthopox viruses applied on one sample also yielded negative results. Three different therapeutical approaches namely surgical excision, cryosurgery, and the use of a topical immune response modifying cream Imiquimod, are discussed.