Cutaneous soft tissue tumours in dogs: classification, differentiation, and histogenesis

Particular difficulty is regularly encountered in differentiating on routine morphological grounds between soft tissue tumours in dogs, especially fibrosarcoma, including myxosarcoma; haemangiopericytoma; and schwannoma. In this study we report the findings of the immunohistochemical examination of 74 canine tumours classified as soft tissue tumours by routine light microscopy. As a consequence, we propose that the morphologic diagnosis of cutaneous fibrosarcoma, haemangiopericytoma or schwannoma carries little precision in respect of tumour cell differentiation, and would support use of the term 'spindle cell tumour of canine soft tissue' to encompass this group of lesions.