Primary Renal Synovial Sarcomas: PAX 8 Immunostaining and Unusual Molecular Findings.

Synovial sarcoma (SS) is a high-grade sarcoma that rarely involves the kidney. Eleven renal SS cases were collected in our institution. Immunostaining features and molecular changes of renal SS were further elucidated in this study. PAX 8 was focally positive in 1 monophasic SS and diffusely positive in both the spindled and epithelial components in 1 biphasic SS. These 2 PAX8 expressing renal SS were confirmed by the presence of the classic t(X;18) translocation. Our study also revealed the presence of extra copies of the SS18 in one biphasic SS and one poorly differentiated SS. The SS18 (SYT) gene rearrangement is useful for confirming the SS diagnosis. However, a negative test (FISH or RT-PCR) does not rule out the diagnosis. Although not as common, other chromosomal alterations, such as polysomy 18, indeed occur in renal synovial sarcoma.

Hypoglycemia in a Patient With a Polyhormonal Pancreatic Neuroendocrine Tumor With Evidence of Endocrine Progenitors.

A 55-year-old woman with a large polyhormonal neuroendocrine tumor with unusual pathology is described. The patient presented with intermittent neuroglycopenic symptoms between more protracted asymptomatic periods occurring over the preceding 4 years. During a diagnostic 72-hour inpatient fast, she exhibited hypoglycemia at 70 hours after initiation. On computed tomography scan, a 6-cm mass was identified at the pancreatic head. The patient underwent a pylorus-preserving pancreaticoduodenectomy, and pathology was positive for cells staining for pancreatic polypeptide, insulin, and occasional double hormone (insulin plus pancreatic polypeptide)-positive cells. In addition, the tumor exhibited broad staining for ALDH1A3, a new marker of endocrine progenitors. This case serves to highlight the clinical and pathologic variability of insulin-producing tumors and raises the potential for cells in these tumors to exhibit hormone interconversion and progenitor-like states.