Spontaneous subcutaneous myxosarcoma in a captive European hedgehog (Erinsceus europaeus).

A surgically excised biopsy representing a subcutaneous mass on the left side of the neck from a 3-year-old female European hedgehog (Erinsceus europaeus) was presented. Spontaneous myxosarcoma was diagnosed based on histological, immunohistochemical, and ultrastructural characteristics. The neoplasm grossly consisted of a firm, pale, multilobulated mass with a characteristic clear gelatinous fluid. Histologically, the neoplasm was nonencapsulated and composed of pleomorphic stellate or spindle-shaped vimentin and periodic acid-Schiff-positive cells arranged in loose sheets and occasionally whorls. The neoplastic cells were suspended in Alcian blue-positive stroma and contained infrequent mitotic figures. Evidence of a viral etiology was not detected using electron microscopy and polymerase chain reaction. This is the first case report of a myxosarcoma in a captive European hedgehog.