Indian Journal of Pathology and Microbiology

CASE REPORT
Year
: 2019  |  Volume : 62  |  Issue : 4  |  Page : 608--610

“Endolymphatic sac tumour”: A case report with review of literature


B Rajeshwari1, Salapathi Shanmugam1, Niamath Sadiya1, Ghosh Mitra1, B Chendilnathan2,  
1 Department of Histopathology, Apollo Speciality Hospitals, Vanagaram, Chennai, Tamil Nadu, India
2 Department of Neurosurgery, Xcellent Care Hospital, Chennai, Tamil Nadu, India

Correspondence Address:
B Rajeshwari
Department of Histopathology, Apollo Speciality Hospitals, Vanagaram, Chennai - 600 095, Tamil Nadu
India

Abstract

Endolymphatic sac tumour (ELST) is a non-metastasizing low grade adenocarcinoma of endolymphatic sac origin. It is also known as Heffner tumour, low grade adenocarcinoma of endolymphatic sac origin and aggressive papillary middle ear tumour. These tumours are closely associated with Von Hippel Lindau (VHL) disease. Here we report a case of Endolymphatic sac tumour in a 63 yr old lady who presented with left sided facial palsy. Since the tumour was highly vascular and required preoperative embolization, initial clinicoradiological diagnosis was Jugulotymphanic paraganglioma. Histopathology showed features of Endolymphatic sac tumour, which was confirmed by immunohistochemistry. Since this tumour is locally aggressive low grade adenocarcinoma, the diagnosis is difficult in advanced cases where there is erosion of petrous temporal bone or the lesion shows extension into cerebellopontine angle as in our case. Since the association of this tumour with VHL disease is well established, it is important to screen all the patients of VHL disease for this lesion and also all the patients of ELST should be screened for other lesions of VHL disease to aid in early diagnosis and treatment. The case is presented here for its rarity and difficulty in initial diagnosis.



How to cite this article:
Rajeshwari B, Shanmugam S, Sadiya N, Mitra G, Chendilnathan B. “Endolymphatic sac tumour”: A case report with review of literature.Indian J Pathol Microbiol 2019;62:608-610


How to cite this URL:
Rajeshwari B, Shanmugam S, Sadiya N, Mitra G, Chendilnathan B. “Endolymphatic sac tumour”: A case report with review of literature. Indian J Pathol Microbiol [serial online] 2019 [cited 2020 Jul 7 ];62:608-610
Available from: http://www.ijpmonline.org/text.asp?2019/62/4/608/269068


Full Text



 Introduction



Endolymphatic sac tumors (ELSTs) are rare neuroectodermal tumors of the dorsal aspect of petrous part of the temporal bone. They have a low malignant potential, and are locally aggressive tumors of the inner ear.[1] They are slow-growing and locally aggressive in nature resulting in late clinical manifestations with expansive mass invading the temporal bone and posterior fossa.[2] It is also known as Heffner tumour, low grade adenocarcinoma of endolymphatic sac origin and aggressive papillary middle ear tumour.[3] They occur rarely in general population but its association with Von Hippel Lindau (VHL) disease is well established.[3] The incidence of ELST in the adult population is 1:30,000 and in the VHL population is around 10%.[1] Mean age of patients with sporadic cases is 52 years, whereas in patients with VHL disease it is 31 years; female-to-male ratio is 2:1 in VHL disease patients and 1:1 in non-VHL disease patients.[1] These tumours are exceedingly rare, with only approximately 200 cases reported in the literature since they were first characterised in the late 1980s.[4] This tumour was underestimated for years and was often misinterpreted as paraganglioma, metastatic renal cell carcinoma, choroid plexus papilloma, ceruminous gland adenocarcinoma, or aggressive papillary tumour. Here we report a case of endolymphatic sac tumour in a 63 year old lady who presented with left sided facial palsy and was clinically and radiologically diagnosed as paraganglioma.

 Case Report



A 63-year-old lady presented with left sided facial palsy. MRI showed a highly vascular intensely enhancing heterogenous illdefined extra axial lesion measuring 3.2 × 2.8 × 2.5 cm in left cerebellopontine angle [Figure 1]. The lesion appeared to be centered in the left jugular foramen, causing remarkable irregular permeative destruction of the medial part of the left mastoid bone [Figure 1]. The lesion caused irregular destruction of the posterior wall of left internal auditory canal with partial destruction of left inner ear structures including facial nerve canal. The lesion bulged into left internal auditory canal and appeared to involve the left 7th and 8th nerve complex. The lesion bulged into left middle ear cavity without obvious involvement of middle ear ossicles. Partial erosion of medial part of left mastoid air cells was noted. Radiologically the possibility of glomus jugulare was suggested. Since the lesion was highly vascular, patient underwent preoperative embolization using 300micron PVA particles and gelfoam shavings. The tumour was removed in piecemeal and was sent for histopathological examination. The specimen was received in histopathology department as multiple grey white to grey brown soft tissue bits admixed with few bone spicules. Microscopically the tumour showed papillary architecture comprising of arborizing papillae lined by single layer of cuboidal epithelium with central fibrovascular core. The cells showed round to oval monomorphic basally placed nuclei with moderate eosinophilic cytoplasm. The tumour eroded through the bone spicules. There was no increase in mitoses or necrosis [Figure 2]. Immunohistochemistry showed positivity for CK, CK5/6, CK7, Vimentin and EMA. S100, Synaptophysin, GFAP, TTF1, CK20, CEA were negative [Figure 3]. Ki 67 proliferation index was <0.1%. The tumour was reported as Endolymphatic sac tumour.{Figure 1}{Figure 2}{Figure 3}

 Discussion



Endolymphatic sac tumour (ELST) was first reported by Hassard et al., in 1984, when a tumour originating in the endolymphatic sac was discovered during an endolymphatic sac decompression for Meniere's disease.[5] In 1988, Gaffey et al. proposed that these tumours be classified as 'aggressive papillary middle ear tumours'.[6] With the aid of histological, ultrastructural and immunohistochemical studies, in1989, Heffner characterized ELST as a tumor deriving from the endolymphatic sac epithelium of the internal ear referring to it as a “low-grade adenocarcinoma”.[7] Benecke et al., subsequently described middle ear tumours with a papillary growth pattern that were more aggressive and associated with significant bone and dural involvement.[8] Aggressive papillary tumours of the temporal bone were reclassified as ELST by Li et al. in 1993 and the World Health Organization tumour classification has now recognised ELST is synonymous with Heffner tumour and aggressive papillary adenoma.[8] Recent studies have confirmed that these tumours arise specifically from the endolymphatic sac/duct tissue.[8] The connection between Von Hippel–Lindau disease and endolymphatic sac tumour was first proposed by Eby et al., in 1988, who described a von Hippel–Lindau disease patient with bilateral lesions and a strong family history.[9] Endolymphatic sac tumour was formally recognized as part of von Hippel–Lindau disease in 1997. The prevalence of von Hippel–Lindau disease patients that develop endolymphatic sac tumour is now estimated to be between 3 to 16%.[10] In our case the patient presented with left sided facial palsy. At the time of presentation patient was clinically diagnosed as jugulotymphanic paraganglioma since the lesion was highly vascular and centered in left jugular foramen and showed extension into left cerebellopontine angle. Histopathological examination of these tumours shows a papillary lesion comprising of papillae lined by single layer of cuboidal epithelium. Mitotic activity is rare. The core of the papillary fronds shows rich vascularity. Areas of fibrosis, hemorrhage, chronic inflammation, cholesterol clefts, and associated reactive changes are frequently found. The differential diagnosis includes paraganglioma, chorioid plexus papilloma, papillary ependymoma, middle ear adenoma, and metastatic carcinoma. Our case was negative for Synaptophysin, S100, CK20, CEA, TTF1 and GFAP, thus the possibilities of paraganglioma, metastatic papillary carcinoma and papillary ependymoma were excluded. Choroid plexus papilloma may be histologically similar to ELST, but it originates in the ventricle and does not invade bone. It is positive for CK, Vimentin and usually positive for S100. EMA and CEA are negative. Retrospectively patient was evaluated for VHL disease and there were no other lesions associated with VHL disease. There was family history of VHL associated lesions in the two siblings of the patient who had had hemangioblastoma of brain and spinal cord. Choroid plexus papillomas form close differential diagnosis in cases where the lesion shows extension into cerebellopontine angle as in our case. However, the clinical, radiographic, and pathologic features that are unique to ELST should allow for distinction. Immunohistochemistry is useful tool in such cases.

 Conclusion



ELST is a locally aggressive low grade adenocarcinoma arising from endolymphatic duct epithelium. The diagnosis is easy in early lesions where the lesion is small and shows retrolabyrinthine location since the origin can be identified radiologically. But in advanced lesions, with involvement of jugular foramen or extension into cerebellopontine angle and presence of extensive bone destruction, as in our case, diagnosis is difficult without immunohistochemistry. Despite controversy surrounding the origin of so-called “aggressive papillary middle ear tumour”, current evidence suggests that it is ELST with extension into the middle ear. The tumour grows slowly over many years and is not known to metastasize. Since the association of this tumour with VHL disease is well established, it is important to screen all patients with VHL for ELST by imaging so that small tumours may be detected early and completely excised. The case is presented here for its rarity and difficulty in initial clinicoradiological diagnosis.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Acknowledgement

We sincerely acknowledge our technical staff, Mr R Bhuvaneshwaran, MrsPShivashankari, Mrs Lavanya Latha, Mrs J Rukmani, for their technical help.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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