ACTA1 and histiocytic sarcoma: In African pygmy hedgehogs (mean age 4.4 years old, age range: 2–7 years; three males, two females), all cutaneous tumours were represented by soft tissue sarcomas: fibrosarcoma, liposarcoma, malignant peripheral nerve sheath tumour, histiocytic sarcoma (tumour cells expressed Iba-1+ and vimentin, clone 3B4, and were negative for desmin and α-SMA-; Figure 6) and poorly differentiated sarcoma (vimentin clone 3B4+, Iba-1-, desmin-, α-SMA-).