CASE 2159 Published on 24.09.2006

Papillary endolymphatic sac tumour

Section

Head & neck imaging

Case Type

Clinical Cases

Authors

Viskovic K, Rumboldt Z

Patient

33 years, female

Categories
No Area of Interest ; Imaging Technique MR, MR, MR, MR
Clinical History
A 33-year-old female patient presented with a two-year history of progressive left-sided hearing loss and a recent onset of ipsilateral facial palsy.
Imaging Findings
A 33-year-old female patient, with von Hippel–Lindau syndrome (VHL), presented with a two-year history of progressive left-sided hearing loss and a recent onset of facial palsy on the left. Five years ago, a cerebellar haemangioblastoma had been successfully resected. On clinical examination, it was found that she had a complete sensorineural hearing loss and complete facial nerve paralysis on the left side. MR imaging showed the presence of a heterogeneous mass with a lobulated contour in the petrous portion of the temporal bone, with destruction of the posterior pyramid and all of the middle and inner ear structures. The lesion extended into the cerebellopontine angle. The tumour had mixed, predominantly high, signal intensity on both T1- and T2-weighted images and showed an intense contrast enhancment.
Discussion
Papillary endolymphatic sac tumours, also known as papillary adenocarcinomas of the temporal bone, or simply endolymphatic sac tumours (EST) are rare aggressive neoplasms, and were first described in 1989 as a distinct entity by Heffner and are sometimes referred to as Heffner's tumours. In the past, it has been presumed that they have a middle ear origin and only recently, it was demonstrated that these tumours arise from the pars rugosa of the endolymphatic sac. The key diagnostic characteristics of EST include the clinical history and distinct radiological appearance, combined with histological findings. These tumours more commonly occur among patients with VHL. EST usually invade the petrous temporal bone as well as the dura mater of the posterior fossa and they may also arise from the distal smooth portion of the endolymphatic sac and extend predominantly from the inner ear to the region of the jugular foramen, sparing the petrous pyramid. The tumour may be found adhering to the ascendenting vertical portion of the petrous carotid artery. Although typically described as histologically nonaggresive lesions, neverthless they are termed adenocarcinomas, since they are often locally invasive. Radiological features consist of a heterogeneous mass arising from the endolymphatic sac and eroding the temporal bone. The bipolar growth pattern, destroying the temporal bone anteriorly and growing toward the CPA, is typical. On CT, the tumuor usually contains calcifications centred in the retrolabyrinthine region. The MR imaging appearance varies with the lesion size: a high signal intensity area on T1-weighted images is usually circumferential in lesions under a size of 3 cm, and is scattered throughout the lesion in advanced tumours. The signal intensity is also typically high on T2-weighted images. This characteristic signal intensity pattern is considered to correspond to blood products, from presumed internal haemorrhages. The lesions are frequently lobulated, and tumours larger than 2 cm may contain flow voids. An angiography when done demonstrated the presence of a hypervascular mass, with the blood supply arising predominantly from the external carotid artery. Large tumours have additional supply from the internal carotid and posterior circulation. A gross total resection should always be attempted, and preoperative embolisation may be helpful. Stereotactically focused radiotherapy may be beneficial to control areas of local tumour invasion and residual or recurrent EST.
Differential Diagnosis List
Papillary endolymphatic sac tumour.
Final Diagnosis
Papillary endolymphatic sac tumour.
Case information
URL: https://eurorad.org/case/2159
DOI: 10.1594/EURORAD/CASE.2159
ISSN: 1563-4086