Kidney tumor
Other tumors
Synovial sarcoma
Author: Sean R. Williamson, M.D.
Topic Completed: 1 July 2012
Minor changes: 1 July 2020
Copyright: 2003-2019, PathologyOutlines.com, Inc.
PubMed Search: "Synovial sarcoma" kidney
Table of Contents
Definition / general | Clinical features | Radiology images | Case reports | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Negative stains | Molecular / cytogenetics description | Molecular / cytogenetics images | Differential diagnosisCite this page: Williamson SR. Synovial sarcoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/kidneytumormalignantsynovialsarcoma.html. Accessed October 20th, 2020.
Definition / general
- Often previously diagnosed as embryonal sarcoma of kidney (Am J Surg Pathol 2000;24:1087)
Clinical features
- Usually extremities of young adults, rare in kidney (< 50 cases reported)
Radiology images
Images hosted on other servers:
CT scan
Case reports
- 21 year old woman (Urol Ann 2011;3:110)
- 40 year old woman (Case of the Week #19)
- 60 year old man (Arch Pathol Lab Med 2005;129:238)
Gross description
- Large, partially necrotic, soft to rubbery mass; smooth walled cyst in 70%
Gross images
Images hosted on other servers:
Beige lobulated tumor with focal necrosis
Upper pole mass
Microscopic (histologic) description
- Usually short, intersecting fascicles of monophasic spindle cells with indistinct cell borders, ovoid nuclei and indistinct nucleoli that infiltrate around nonneoplastic, dilated renal tubules
- Often foci with hemangiopericytoma-like vascular pattern; cysts lined by hobnail epithelium
- Rarely rhabdoid (Am J Surg Pathol 2004;28:634), biphasic (epithelial and spindle cells) or poorly differentiated (sheets of undifferentiated round cells with scant cytoplasm and high grade nuclei)
- Also large cell epithelioid variant, small cell variant and high grade spindle cell variant
Microscopic (histologic) images
Case of the Week #19
Various images
Images hosted on other servers:
Various images
Clear cell change and plump spindled cells
Hemangiopericytoma-like vascular pattern
bcl2+, EMA+ (focal), CD99+, CD34-
Pleural tumor
Cytology description
- Malignant biphasic tumor (one case) characterized by minimally atypical tubular epithelium, immature spindle cells and foci of coagulative tumor necrosis (Acta Cytol 2003;47:668)
Positive stains
- CD56, CD99, vimentin
- Variable bcl2, calponin and EMA
- PAX2 and PAX8 often positive in epithelial cysts of primary renal cases, likely due to entrapment and dilation of renal tubules; however, spindled and epithelial components of biphasic synovial sarcoma in general may have weaker positivity (Am J Surg Pathol 2011;35:1264)
Negative stains
- Keratin (usually), S100, CD34, smooth muscle actin, desmin
Molecular / cytogenetics description
- SYT-SSX2 transcript due to t(X;18)(p11.2;q11.2) in > 90% of cases
Molecular / cytogenetics images
Images hosted on other servers:
FISH and karyotype (site unspecified)
Differential diagnosis
- Ewing's sarcoma / PNET: neuroendocrine features including rosettes, CD56-, different translocation
- Hemangiopericytoma: minimal cellular pleomorphism, staghorn vascular pattern, no / rare mitotic activity, CD34+, no SYT-SSX2
- Malignant peripheral nerve sheath tumor: more pleomorphic cells with tapering nuclei, S100+, keratin-, CD99-, no SYT-SSX2
- Metastatic sarcoma: clinical history of primary, no SYT-SSX2
- Primary retroperitoneal sarcoma: kidney is not primary location, no SYT-SSX2
- Sarcomatoid renal cell carcinoma: has primary renal cell carcinoma component, sarcomatoid area is often EMA+, vimentin+, no SYT-SSX2
- Solitary fibrous tumor: collagen fibers, hemangiopericytoma-like vascular pattern, CD34+, no SYT-SSX2
