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Open Access Case Report

Endolymphatic sac tumor: case report and review of the literature

Yan-Hua Sun1, Wen Wen1*, Jun-Hui Wu1, Jian-Ming Song1, Hong Guan1, Kai-Xin Wang2 and Mei-Quan Xu1

Author affiliations

1 Department of Pathology, Shenzhen Second People's Hospital, 3002 Sungang West Road, Shenzhen 518035, China

2 Department of Pathology, Shenzhen Nanshan District People's Hospital, 89 TaoYuan Road, Shenzhen 518067, China

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Citation and License

Diagnostic Pathology 2012, 7:36  doi:10.1186/1746-1596-7-36

Published: 2 April 2012

Abstract

Endolymphatic sac tumor (ELST) is a rare neoplasm which can be encountered sporadically or in Von Hippel-Lindau (VHL) disease. Here we report a sporadic case of ELST in 31-year-old man. Neither the symptoms nor a family history of VHL disease were found in the patient. CT imaging demonstrated an expansile lytic lesion of the mastoid process of the left petrous bone. MR scanning revealed a 5.2 cm × 4.7 cm × 4.2 cm mass which showed hyperintensity on T1- and T2-weighted images. Histologic sections showed a papillary, cystic or glandular architecture. The papillary and glandular structures were lined by a single layer of flattened cuboidal-to-columnar cells. The stroma of the papillary fronds was richly vascularized and chronically inflamed. The tumor showed diffusely positive reactivity with cytokeratin (Pan), cytokeratin 19, cytokeratin 5/6, cytokeratin 7, EMA, vimentin, CD56, and NSE and also showed variable reactivity with glial fibrillary acidic protein (GFAP) and VEGF. The Ki-67 immunostain showed a proliferation index of < 1%. Because the mass was large, it was difficult to extirpate surgically. After surgery, the patient underwent gamma-knife radiosurgery for residual tumor. The findings indicate that ELST is a rare neoplasm with benign histopathological appearance and clinically destructive behavior. Because of the rarity of this tumor, it can easily be confused with other tumors such as paraganglioma, middle ear adenoma, adenocarcinoma, papillary carcinoma of thyroid or choroid plexus papilloma. Owing to its locally aggressive nature, it is difficult to extirpate surgically when it is large.

Virtual Slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/7973320646763012 webcite

Keywords:
Endolymphatic sac tumor; ELST; Heffner tumor; Aggressive papillary middle ear tumor; von Hippel-Lindau disease