Journal of Cancer Research and Therapeutics Medknow Publications on behalf of the Association of Radiation Oncologists of India (AROI) ISSN: 0973-1482 EISSN: 1998-4138 Vol. 6, Num. 4, 2010, pp. 540-542

Journal of Cancer Research and Therapeutics, Vol. 6, No. 4, October-December, 2010, pp. 540-542

Case Report

Endolymphatic sac papillary carcinoma treated with surgery and post-operative intensity-modulated radiotherapy: A rare case report

Rajni Gupta¹, AN Vaidhyswaran¹, V Murali², Mohan Kameswaran³

¹ Department of Radiation Oncology, Apollo Speciality Hospital, Mount Road, Chennai, India
² Department of Medical Physics, Apollo Speciality Hospital, Mount Road, Chennai, India
³ Department of ENT, Madras ENT Reseach Foundation, Chennai, India

Correspondence Address: Rajni Gupta, Apollo Speciality Hospital, Padma Complex, 320, Anna Salai, Chennai - 600 035, India, rajni1968@hotmail.com

Code Number: cr10132

PMID: 21358096

DOI: 10.4103/0973-1482.77062

Abstract

Keywords: Intensity modulated radiotherapy, papillary neoplasm, surgical excision, temporal bone

Introduction

Endolymphatic sac tumor (ELST; Heffner′s tumor)^[1] is a rare, hyper-vascular, low-grade adenocarcinoma that originates in retro-labrynthine part of the temporal bone. They classically grow very slowly, resulting in late clinical manifestations with an expansile mass invading temporal bone and extending onto the posterior cranial fossa. The main symptoms include vertigo, sensori-neural hearing loss and lower cranial nerve deficits. ^[2] These tumors are locally invasive and metastasize very rarely. Different histological patterns include follicular, papillary or solid structures. Immuno-histochemical analysis usually reveals cytokeratin, vimentin, epithelial membrane antigen and less frequently S-100 protein or neuron-specific enolase. ^[3],[4] Most of them are sporadic ^[5] but 30% of the cases show association with von Hippel-Lindau (VHL) disease. Till now 88 cases have been reported in the literature. One such case was referred to us after near-total excision, which was treated with intensity modulated radiotherapy (IMRT).

Case Report

A 33-year-old gentleman was presented with symptoms of vertigo, hearing loss in the left ear, tinnitus and imbalance on walking since 3 years. CT scan [Figure - 1] of the temporal bone showed an irregular moth-eaten destructive lesion with central calcific speculations centered over the posterior aspect of left petrous temporal bone, just abutting the Jugular fossa in the region of the endolymphatic sac. MRI scan of the brain and inner ear showed a hyper-intense heterogeneous lesion on T2-weighted images in the left endolymphatic sac region. The vestibulo-cochlear nerve bundles, cerebellum and the Cerebello-Pontine angles were all normal.

Owing to the proximity of the lesion to the jugular foramen, a high suspicion of a glomus tumor arose but selective carotid artery/jugular venous angiography did not reveal any feeding vessel. Other provisional differential diagnosis for the solitary lytic lesion in the posterior cranial fossa like Eosiniphilic Granuloma, Paraganglioma, Hyper-parathyroid lesion and Metastatic deposit (from thyroid, lung or breast) were considered. As the possibility of a neoplastic lesion (either primary or metastatic) was present, a meticulous evaluation to identify any other primary site was done. An ultrasound of neck, FNAC thyroid and thyroglobulin studies proved negative. As there is a strong syndromic association of a primary neoplasm of the endolymphatic sac with VHL disease, diagnostic tests for VHL disease including a fundoscopy to rule out retinal hemangiomas, CT abdomen to exclude liver or adrenal tumors, biochemical markers for neuro-endocrine tumors, MRI of the brain with spine (to locate any angiomatous lesions) and a genetic study for VHL were performed and found to be normal.

After ruling out all these possibilities, excision of the left endolymphatic sac lesion was performed.

Histopathological examination confirmed the diagnosis of an ELST with characteristic malignant papillary epithelial clusters with hyper-chromatic nuclei and a glandular stroma containing eosinophilic colloid-like material.

Patient was referred to us for post-operative radiotherapy. In view of the young age of patient with unilateral deafness and close vicinity of the residual tumor to the critical structures, it was important to minimize the dose to opposite cochlea and brain stem. 3DCRT and IMRT plans were done [Figure - 2]. Comparative study of the two showed better conformity index (1.06 vs. 1.38) for IMRT. Five per cent of the volume of brain stem received 49.5% and 60% and 50% of the volume received 20% and 18% of the dose per fraction and opposite cochlea received less than 3 Gy in total to 5% of the volume whereas 100% of the volume received 3.6 Gy in IMRT and 3DCRT, respectively. Hence a dose of 60 Gy was given in 30 fractions to the CTV by IMRT technique from 13 ^th September′07 to 26 ^th October′07. Follow-up MRI scan [Figure - 3] after completion of 1 year shows no evidence of any residual tumor. Although hearing remains status quo, tinnitus and vertiginous spells have subsided.

Discussion

ELSTs have been known as an individual tumor entity since 1984. ELSTs may occur as solitarily and sporadically or as a hereditary manifestation associated with VHL disease. ^[5] The latter association was first observed in 1992 and confirmed by molecular genetic analysis of the VHL gene. There is an abnormal growth of multiple tumors in parts of the body which are rich in blood supply (like liver, lung, brain, kidney, pancreas and adrenal gland). ^[4],[5],[6] ELSTs associated with a diagnosis of VHL disease appear to affect a younger population and women twice as often as in men. It is more frequently bilateral and advanced as opposed to the non-VHL disease patient. ^[7]

Histologically, they have a follicular or papillary and adenoid pattern that can be easily confused with various other neoplastic conditions ^[8],[9] Papillary ELSTs of the temporal bone are rare, slow growing and aggressive neoplasms, with an incidence of ~ 1:30,000 in adult population. The symptoms are usually auditory, with a constant sensori-neural deafness of sudden onset in 50% of cases along with tinnitus and vertigo. Those tumors with medial extension result in a cerebello-pontine angle syndrome. The cause of sensori-neural hearing loss has been implicated to the otic capsule invasion, tumor-associated intra-labyrinthine hemorrhage or due to endolymphatic hydrops. ^[10]

Surgical excision is the treatment of choice, but sacrifice of the vestibule-cochlear nerve and facial nerve may be needed in advanced cases to achieve complete tumor clearance. If complete resection is not possible due to extensive local invasion, adjuvant radiotherapy is advocated in order to achieve tumor regression and to preserve the integrity of surrounding vital structures in the posterior cranial fossa. This is the first rare case reported at this institution in 20 years of our experience in neuro-oncology where we found that IMRT definitely has an edge over 3DCRT in its treatment.

References

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