Cutaneous Hemangioma in a dog
History: Numerous skin lesions previously diagnosed with mast cell tumors.
Within the dermis of the second biopsy on slide 2 is an unencapsulated, poorly demarcated neoplasm of endothelial-lined vascular channels ranging from 100-200 um in diameter within a collagenous stroma. Neoplastic endothelial cells are flattened with scant eosinophilic cytoplasm and oval nuclei with finely stippled chromatin and central nucleoli. There is moderate anisocytosis and anisokaryosis with rare mitotic figures. The neoplasm appears completely excised.
1) Haired skin: Cutaneous hemangioma
This is a classic example of a hemangioma, a benign neoplasm of endothelial cells forming capillary-like channels in the skin. Hemangiomas are sometimes divided into capillary or cavernous varieties depending on the size of the vascular channels. The well-formed vascular channels, the well-demaracted expansile formation, and the normal-appearing endothelial cells indicate that this is a benign neoplasm. Hemangiosarcomas of the skin are locally infiltrative, form anastomosing irregular channels, and are lined by plump endothelial cells.
This dog had multiple skin neoplasms including mast cell tumors and sebaceous adenomas along with the hemangioma. This case highlights the need to examine each tumor individually, since some of these neoplasms were potentially malignant.