Cytology of Endolymphatic Sac Tumor

Abstract

Endolymphatic sac tumors (ELST) are extremely rare neoplasms that arise in the endolymphatic sac in the posterior-medial petrous portion of the temporal bone. Although the clinicopathologic and radiographic features have been well documented, the cytologic features of ELST have not been previously described (1-5). We report the cytologic findings of an ELST from the cyst fluid of a recurrent ELST in the left temporal region of a 77-year-old man. CASE REPORTA 77-year-old white man presented in the fall of 1999 with decreased mental status and magnetic resonance imaging results demonstrating an enhancing tumor mass along the left tentorium with multiple adjacent cysts, the largest of which was approximately 4.3 cm ϫ 3.8 cm. A midline shift was present. The patient had a history of left mastoidectomy performed at another institution for an "auditory canal" tumor originally diagnosed in the 1970s. In 1989, the tumor recurred, and he underwent left petrosectomy, also at another institution where the diagnosis was a ceruminous gland tumor. A consultant's opinion of that material was that it represented an adenocarcinoma of endolymphatic sac origin. For the patient's most recent surgery, he was taken to the operating room for left temporal-parietal craniotomy for tumor debulking and cyst drainage. The cyst fluid was described by the surgeon as yellow tinged. The patient's surgery was without complications, and he was subsequently released from the hospital.

Cerebrospinal fluid cytology of an endolymphatic sac tumor

“…A single case report of cyst fluid cytology has been published; the fluid showed rare epithelial cell clusters, some with papillary features. Tumor cells were orderly with bland nuclei and well‐defined borders …”

“…Endolymphatic sac tumors are rare, locally aggressive papillary neoplasms which arise from the endolymphatic sac of the inner ear and usually demonstrate posterior fossa extension . The clinical, radiologic, and histopathologic characteristics of these neoplasms have been well described, and there has been a single case report of aspirated cyst fluid cytology in a recurrent ELST . To the best of our knowledge, this is the first report on cytologic CSF findings in an ELST.…”

Endolymphatic sac tumor at the cerebellopontine angle: A case report and review of literature

“…In fact, these tumors may be mistaken for metastatic papillary thyroid carcinoma. Immunohistochemically, these tumors are positive for cytokeratin with a minority displaying positivity for S-100 protein, GFAP synaptophysin and Leu 7 [18]. ELST behave as low grade carcinomas: they may destroy bone and brain parenchyma and recur.…”

An unusual middle-ear mass

“…Endolymphatic sac tumours are now thought to be distinct from middle-ear adenomas, which cause middle-ear masses but are rarely associated with bone destruction 12 . The histology of adenomas is usually that of mixed pleomorphic tumour, rather than the papillary cellular pattern seen in endolymphatic sac tumours 13 . Carcinoid tumours are considered by some to be a subtype of mixed pleomorphic adenomas.…”