Endolymphatic sac tumor associated with a Von Hippel-Lindau disease patient: An immunohistochemical study

The authors report a case of endolymphatic sac tumor (ELST) associated with Von Hippel-Lindau disease (VHL), A 20-year-old female VHL patient received a resection of a cerebellar hemangioblastoma 3 years ago and she had a co- existing of left petrous tumor. The petrous tumor showed a remarkable progr ession in 3 years and was resected subtotally. Histologically, the resected petrous tumor showed a papillary structure containing cuboidal or columnar cells with fibrous stroma and numerous microvessels and destructed tempora l bone, all of which are consistent with ELST, We studied the expression of various kinds of cytokeratins (CKs) immunohistochemically and found distin ct expression of CKs (CAM 5.2, 34 betaE-12, CK7, CK8 and CK19), but not for CK10/13 or CK20. Vascular endothelial growth factor and neuron specific en olase showed strong immunoreactivity in the tumor cells. CD34 also had weak expression. Ki-67 antigen (MIB-1) immunoreactivity was found in focal area s, and the labeling index in the highest-density area was 48.9%, These find ings suggest that vascular endothelial growth factor overexpression is an i mportant factor for angiogenesis in ELST, much Like other VHL-associated tu mors, and that ELST may have a more highly aggressive component than the lo w-grade malignancy noted in previous reports.