Synovial Sarcoma Case # Michael W. Nolan, Anya C. Hawthorn and Bernard S. Jortner Department of Biomedical Sciences and Pathobiology Virginia-Maryland Regional College of Veterinary Medicine Virginia Polytechnic Institute and State University Blacksburg, VA Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

History Adult dog Adult dog Mass at point of right hock Mass at point of right hock Surgically excised Surgically excised Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Gross Findings Pale solid mass Pale solid mass Several centimeters diameter Several centimeters diameter Found in close association with the distal calcaneal tendon Found in close association with the distal calcaneal tendon Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Histologic Description - H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Histologic Description - H&E Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Histologic Description - Immunohistochemistry Cytokeratin Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Histologic Description - Immunohistochemistry Vimentin Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Histologic Description -Special Stains PAS Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Histologic Description -Summary Lined clefts Lined clefts 2 cell populations 2 cell populations Epithelioid cells Epithelioid cells Spindloid cells Spindloid cells Cytokeratin negative Cytokeratin negative Vimentin positive Vimentin positive PAS negative PAS negative Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Morphologic Diagnosis Synovial cell sarcoma Synovial cell sarcoma biphasic biphasic Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion Synovial Sarcoma Synovial Sarcoma epithelial and/or mesenchymal epithelial and/or mesenchymal Classification Classification biphasic (epithelial and mesenchymal) biphasic (epithelial and mesenchymal) monophasic (epithelial or mesenchymal) monophasic (epithelial or mesenchymal) undifferentiated small cell sarcoma undifferentiated small cell sarcoma Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion Are they really synovial in origin? Are they really synovial in origin? Anatomic location Anatomic location Immunoreactivity for vimentin and cytokeratin Immunoreactivity for vimentin and cytokeratin Production of basement membrane Production of basement membrane Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion Are they really synovial in origin? Are they really synovial in origin? Anatomic location Anatomic location many are para-articular many are para-articular ~10% intra-articular ~10% intra-articular mediastinum, heart, lung, kidney, prostate, etc. mediastinum, heart, lung, kidney, prostate, etc. Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion Are they really synovial in origin? Are they really synovial in origin? Immunoreactivity for vimentin and cytokeratin Immunoreactivity for vimentin and cytokeratin usually immunoreactive for vimentin usually immunoreactive for vimentin variably immunoreactive for cytokeratin variably immunoreactive for cytokeratin Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion Are they really synovial in origin? Are they really synovial in origin? Production of basement membrane Production of basement membrane not a feature of normal synovium not a feature of normal synovium Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion Are they really synovial in origin? Are they really synovial in origin? Arise from pleuripotent stem/progenitor cells Arise from pleuripotent stem/progenitor cells example = poorly differentiated synoviocyte example = poorly differentiated synoviocyte Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion So was this really a case of synovial sarcoma? So was this really a case of synovial sarcoma? Extra-articular, in close association with joint Extra-articular, in close association with joint Immunoreactivity: vimentin (+), cytokeratin (-) Immunoreactivity: vimentin (+), cytokeratin (-) PAS (-) PAS (-) Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion What is the biological behavior of synovial sarcoma? What is the biological behavior of synovial sarcoma? Locally invasive Locally invasive Non-metastatic Non-metastatic Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Discussion Biological behavior guides treatment: Biological behavior guides treatment: Wide excision and adjunct chemotherapy Wide excision and adjunct chemotherapy Radical resection/limb amputation Radical resection/limb amputation Fair/good prognosis for survival Fair/good prognosis for survival Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

References Craig LE, Julian, ME, Ferracone JD (2002) The diagnosis and prognosis of synovial tumors in dogs: 35 cases. Veterinary Pathology 39: Fairley R (2002) Letter to the editor. Veterinary Pathology 39(3): Llomart-Bosch A, Lopez-Guerrero JA, Peydro-Olaya A (2002) Synovial sarcoma (ss): new perspectives supported by modern technology. Arkiv Patologii (Archives of Pathology Rus.) 3: Suster S, Moran CA (2005) Primary synovial sarcomas of the mediastinum: a clinicopathologic, immunohistochemical, and ultrastructural study of 15 cases. American Journal of Surgical Pathology 29(5): Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only

Questions? Presented at SEVPAC 2008 – Permission granted for use on SEVPAC website only