Cutaneous haemangiosarcoma in an elderly dog

An 11-year-old Lurcher presented with a solitary subcutaneous mass on its left flank. Fine needle aspirates were initally taken from the mass and following the cytology result, surgical resection and histopathology were performed.

Fig 1. FNAB. The smears contain a large amount of blood and scattered clumps of cells. Modified Wrights-Giemsa x40.
Fig 2. FNAB. The cells are not that well-preserved but reflect large neoplastic spindeloid cells, many of which contain intracytoplasmic RBCs (see the cell on the top left). Modified Wrights-Giemsa x400.
Fig 3. Histopathology. The deep dermis, subcutis and underlying muscle are infiltrated by a highly cellular, vasoformative neoplasm. H&E x40.
Fig 4. Histopathology. A closer look at the neoplastic endothelial cells, forming interconnecting blood-filled channels. H&E x200.

Final Diagnosis

Haemangiosarcoma

Discussion

Haemangiosarcomas are malignant, locally infiltrative neoplasms of vascular (endothelial) origin and post-surgical recurrence can be problematic. These tumours can potentially arise within any tissue, including the skin, deep subcutis and/or muscle. Primary cutaneous tumours do carry metastatic potential (especially to lungs) but the metastatic rate is lower compared to their visceral counterparts. Less commonly, metastatic lesions may occur in the skin from a primary haemangiosarcoma elsewhere (e.g. splenic, hepatic, cardiac or bone).