Auris Nasus Larynx 42 (2015) 163–166

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A case of atypical teratoid/rhabdoid tumor in the internal auditory canal Tomoko Yamaguchi a,*, Hidehiro Oka b, Chihiro Kijima b, Hajime Sano a, Hiroyuki Watanabe a, Makito Okamoto a a b

Department of Otolaryngology of the Kitasato University Hospital, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0374, Japan Department of Neurosurgery of the Kitasato University Hospital, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0374, Japan

A R T I C L E I N F O

A B S T R A C T

Article history: Received 10 July 2014 Accepted 18 September 2014 Available online 27 October 2014

Objective: The case of a thirteen-year-old woman showing an atypical teratoid/rhabdoid tumor (AT/RT) primarily occurred in the internal auditory canal was presented. Results: There was a delay in diagnosing AT/RT because of the first histological diagnosis of benign neurofibroma. If we had changed the surgical approach to one which was middle cranial fossa-based or translabyrinthine in the second or third operation, we might have reached an earlier final diagnosis. Although we faced a dilemma about whether to sacrifice facial nerve function for dissection of the tumor, we should have considered the possibility of malignancy at an earlier stage. Conclusion: This is a case report of AT/RT in the internal auditory canal presenting with progressive hearing loss as the initial symptom. Although no previous reports of AT/RT primarily occurring in the internal auditory canal are existent, this rare form of the disease should be considered in future evaluations as a differential diagnosis for internal auditory canal tumor. ß 2014 Elsevier Ireland Ltd. All rights reserved.

Keywords: Internal auditory canal tumor Rapidly progressive hearing loss Facial palsy

1. Introduction Approximately 50–60% of atypical teratoid/rhabdoid tumors (AT/RT) occur in structures in the posterior fossa such as the cerebellum, and other AT/RTs originate in the cerebral hemisphere and in other parts of the central nervous system. To date, no reports have shown an AT/RT patient with the tumor primarily located in the internal auditory canal with an initial symptom of hearing loss. Herein, we report such a case and discuss the difficulties in reaching a final diagnosis.

2. Clinical history A 13-year-old female presented at our hospital with gradually progressing hearing loss in her right ear, which started three weeks before admission (day 1). An audiogram at the initial visit showed slight low-tone sensorineural hearing loss of 30 and 35 dB at 125 Hz and 250 Hz, respectively (Fig. 1). She was treated with oral steroids in an outpatient setting. However, her hearing impairment

and tinnitus deteriorated after the initial visit. She experienced a headache on the ipsilateral side four days later. Twenty days after the initial visit, her right ear hearing levels were over 100 dB at 1000, 2000, 4000, and 8000 Hz (Fig. 1). An auditory brainstem response test on the right side showed no response. Right stapedius reflex was negative with right-side stimulation, however, it was positive with left-side stimulation. The maximum slow phase eye velocity (max SPEV) determined by the air caloric test was 10.8 deg/s bilaterally, which suggested canal palsy (Table 1). The patient did not have a family history of neurofibromatosis. She did not present with any skin lesions, tumors of nervous system, or juvenile cataract. Magnetic resonance imaging (MRI) performed on day 9 revealed a mass 8 mm in diameter visualized by iso-signal intensity on T1-weighted imaging and low signal intensity on T2-weighted imaging, and there was a strong enhancement with gadolinium in the right auditory canal (Fig. 2-1). In addition, right peripheral facial paralysis developed to House–Brackmann grade III on day 54. 2.1. First operation and postoperative course

* Corresponding author. Tel.: +81 042 778 8111. E-mail addresses: [email protected], [email protected] (T. Yamaguchi). http://dx.doi.org/10.1016/j.anl.2014.09.005 0385-8146/ß 2014 Elsevier Ireland Ltd. All rights reserved.

Surgery was performed by neurosurgeons at our hospital 97 days after the initial visit. The patient was operated using a lateral suboccipital retrosigmoid transmeatal approach. The tumor was

T. Yamaguchi et al. / Auris Nasus Larynx 42 (2015) 163–166

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dBHL 20 10 0

125

250

500

1,000

2,000

4,000

Hz 8,000

Day 1

10 20 30 40 50 60 70 80 90 100

Table 1 The results of audiological examination. Examination

Right side

Left side

ABR Day 20 Air caloric test max SPEV Day 20 Stapedius reflex Day 20

No response 10.8 deg/s

Normal 10.8 deg/s

Ipsi ( ) Contra (+)

Ipsi (+) Contra ( )

Auditory brainstem response (ABR) test on the right side showed no response. Maximum slow phase eye velocity (max SPEV) determined by the air caloric test was 10.8 deg/s bilaterally. Stapedius reflex was lost on the right side. ipsi, ipsilateral; contra, contralateral.

after the operation with clear consciousness. She manifested House–Brackmann grade III facial palsy same as preoperative grade and deafness on the right side, but had no trouble walking. After the operation, MRI showed that the residual tumor had expanded to the brain stem (Fig. 2-2). 2.2. Second operation and postoperative course

110 120 Fig. 1. An audiogram at the initial visit showed low tone sensorineural hearing loss of 30 and 35 dB at 125 Hz and 250 Hz, respectively. Twenty days after the initial visit, the patient’s right hearing levels were over 100 dB at 1000, 2000, 4000, and 8000 Hz.

mildly adhered to the inferior cranial nerve, cerebellum, and brain stem. Most of the tumor was found in the internal auditory canal. Deterioration of the facial nerve stimulatory response was observed; therefore, the tumor was not completely resected. Histopathologically, only the scarred vestibular nerve was observed (Fig. 3). We diagnosed the tumor as neurofibroma after histopathological examination. The patient was discharged 7 days

A second operation was also performed by neurosurgeons 351 days after the initial visit, using the lateral suboccipital retrosigmoid transmeatal approach again. We resected half of the tumor and left most of the tumor capsule. Histopathological examination confirmed that the second tumor was a reactive granulation. Despite the administration of betamethasone 8 mg to suppress granulation tissue after the second operation, the tumor increased remarkably and invaded the right inner ear 359 days after the initial visit as determined by MRI. However, we still could not exclude the possibility of neurofibromatosis, because the contralateral abducens nerve was gradually thickening (Fig. 2-3) and a small nodulous lesion was found in left internal acoustic meatus (Fig. 2-4).

Fig. 2. (1) Magnetic resonance imaging (MRI) performed at nine days after the initial visit revealing a mass 8 mm in diameter visualized by low signal intensity on T2weighted imaging in the auditory canal. (2) The residual tumor gradually extruded into the brain stem 178 days after the initial visit as determined by MRI. (3) Significant tumor growth and invasion to the right inner ear at 359 days after the initial visit observed on T1-weighted MRI in the horizontal plane. (3 and 4) The gradually thickened contralateral abducens nerve and left internal acoustic meatus exhibiting a node.

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which invading multilocularly in cerebellum and brain stem. Therefore we could not resect the tumor sufficiently. Finally, after the third surgery, we diagnosed the tumor as AT/ RT by means of histopathological examination on the basis of the presence of rhabdoid cells and negative immunostaining for integrase interactor 1 [INI 1 or human sucrose nonfermenting (SNF) 5; Fig. 4]. We re-examined the histological findings of specimens resected in the second operation, and we detected AT/ RT in a limited portion. The patient died 438 days after the initial visit. 3. Discussion

Fig. 3. Histopathological findings from the initial operation. The tumor cells had long thin nucleii and collagen fibers growing in bundles. Palisading pattern was not observed. Tumor cells were S-100 positive as shown by immunostaining.

Her level of consciousness gradually deteriorated, and she developed Bruns nystagmus and IV, V, VI, VII, VIII, IX, XI, and X11 cranial nerve palsies. 2.3. Third operation and postoperative course We performed a third operation to retrieve a sufficient amount of tumor tissue for histological diagnosis 418 days after the initial visit. The tumor sample was excised through the lateral suboccipital retrosigmoid transmeatal approach again. While resecting the tumor, we found a very hard fibrillar tumor element

AT/RT is newly included in the 2000 World Health Organization classification system [1]. Over 90% of AT/RT occur in children under five years of age. AT/RT are extremely malignant grade IV brain malignancies with an incidence of 1–2% in pediatric brain tumors [1]. The clinical symptoms are usually nonspecific. The most common symptoms are nausea and vomiting as a result of increased intracranial pressure in infants [1]. Symptoms such as headache and weakness of the limbs increase with age [1]. Common cranial nerve disorders are abducens nerve palsy and facial palsy [2]. Supratentorial tumors are 1.3 times more common than subtentorial tumors [1,2]. Moreover, supratentorial tumors mostly arise in the cerebral hemisphere and along the lateral cerebral ventricle, and rarely in the suprasellar or pineal region [1,2]. Subtentorial tumors generally arise in the cerebellar hemisphere, cerebellopontine angle, and brain stem. Most of the patients who are less than two years old exhibit subtentorial tumors [1,2]. Computerized tomography and MRI of AT/RT show findings similar to medulloblastoma or primitive neuroectodermal tumors (PNET) [2]. In fact, the tumor displayed low and iso-intensity on MRI T1-weighted imaging and iso- and high intensity on T2

Fig. 4. Histopathological findings from the third operation. Rhabdoid cells were observed and immunostaining for integrase interactor 1 (INI-1) was negative. Histopathologically, all tumor cells are vimentin positive, but select tumor cells are epithelial membrane antigen (EMA), and a-smooth muscle actin (a-SMA) positive.

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weighted imaging; gadolinium-enhanced T1-weighted imaging demonstrated heterogeneous enhancement. These findings indicate cyst formation, necrosis, and bleeding of the tumor [2]. AT/RT contains a heterogeneous mix of rhabdoid, primitive neuroectodermal, epithelial, mesenchymal, neural, and glial cells [2]. These tumors are characterized by INI-1 gene inactivation [2]. The INI-1 gene is located in the 22q11.2 chromosome and belongs to the switch 1/SNF chromatin-remodeling complex that regulates chromatin structure and engages transcriptional activation [3]. Absence of INI-1 expression induces the dysfunction of the tumorsuppressor gene. It is necessary to histologically distinguish AT/RT from medulloblastoma, germ cell tumor, choroid plexus carcinoma, [4] and ependymoma [5]. Brain neoplasms such as medulloblastoma, PNET, and ependymoma express INI-I protein [6], which was not found in our patient; therefore, these neoplasms were ruled out. AT/RT is distinguished from germ cell tumors by the absence of placental alkaline phosphatase [7]. It is relatively easy to diagnose AT/RT with the presence of typical rhabdoid cell, but it is not easy in a case of lack of rhabdoid cell and a case with predominance of PNET cell [8]. AT/RT has an extremely poor prognosis and a therapeutic strategy has not been established yet. It has been reported that survival seldom exceeds two years [7]; however, recently, some reports have shown an improved outcome [9–11]. Surgical removal of AT/RT has a positive impact on the outcome. The median survival time after total resection is 21.3 months, which is significantly longer than partial resection or biopsy [9–11]. A combination of chemotherapy and radiation therapy is usually administered as adjuvant therapy after surgery. To date, no reports of tumors primarily limited to the internal auditory canal have appeared in the literature. In our case, we speculate that the origin of the tumor was the right cochlear nerve, on the basis of the following reasons: (1) a preoperative caloric test indicated that the function of the superior vestibular nerve was preserved; (2) the stapedius reflex indicated right cochlear nerve disorder and preservation of right facial nerve function; and (3) symptoms included hearing loss followed by facial palsy. The fact that the first surgical specimen did not contain any tumor tissue could support the hypothesis of cochlear nerve origin. In this patient, rapidly progressing hearing loss from mild to total deafness within one month reflects the rapid proliferation potential of AT/RT. There was a delay in diagnosing AT/RT because of the first histological diagnosis of benign neurofibroma. Although we faced a dilemma about whether to sacrifice facial nerve function for dissection of the tumor, we should have considered the possibility of malignancy at an earlier stage. If we had changed the surgical approach to one which was middle cranial fossa-based or translabyrinthine in the second or third operation, we might

have reached an earlier final diagnosis. However the prognosis of this malignant case might have been poor, regardless of the surgical approach. 4. Conclusion This is a case report of AT/RT in the internal auditory canal presenting with progressive hearing loss as the initial symptom. Although, we initially diagnosed it as neurofibroma, the final diagnosis was AT/RT. The tumor was diagnosed based on neuronal biopsy three times before we reached the definitive diagnosis. Although no previous reports of AT/RT primarily occurring in the internal auditory canal are existent, this rare form of the disease should be considered in future evaluations as a differential diagnosis for internal auditory canal tumor. Conflict of interest None of the authors has any conflict of interest, financial, or otherwise. References [1] Kleihues P, Cavenee WK. Pathology and genetics of tumours of the nervous system. Lyon: International Agency for Research on Cancer; 2000. p. 123–48. [2] Judkins AR, Eberhart CG, Wesseling P. Atypical teratoid/rhabdoid tumor. In: Louis DN, et al., editors. WHO classification of tumours of the central nervous system. Lyon: International Agency for Research on Cancer; 2007. p. 147–9. [3] Kalpana GV, Marmon S, Wang W, Crabtree GR, Goff SP. Binding and stimulation of HIV-1 integrase by a human homolog of yeast transcription factor SNF5. Science 1994;266:2002–6. [4] Schittenhelm J, Nagel C, Meyermann R, Beschorner R. Atypical teratoid/rhabdoid tumors may show morphological and immunohistochemical features seen in choroid plexus tumors. Neuropathology 2011;31:461–7. [5] Burger PC, Yu I-T, Tihan T, Friedman HS, Strother DR, Kepner JL, et al. Atypical teratoid/rhabdoid tumor of the central nervous system: a highly malignant tumor of infancy and childhood frequently mistaken for medulloblastoma: a Pediatric Oncology Group study. Am J Surg Pathol 1998;22:1083–92. [6] Han L, Qiu Y, Xie C, Zhang J, Lv X, Xiong W, et al. Atypical teratoid/rhabdoid tumors in adult patients: CT and MR imaging features. AJNR Am J Neuroradiol 2011;32:103–8. [7] Oka H, Scheithauer BW. Clinicopathological characteristics of atypical teratoid/rhabdoid tumor. Neurol Med Chir (Tokyo) 1999;39:510–8. [8] Rorke LB, Packer RJ, Biegel JA. Central nervous system atypical teratoid/ rhabdoid tumors of infancy and childhood: definition of an entity. J Neurosurg 1996;85:56–65. [9] Arcaro A, Doepfner K, Boller D, Guerreiro A, Shalaby T, Jackson S, et al. Novel role for insulin as an autocrine growth factor for malignant brain tumour cells. Biochem J 2007;406:57–66. [10] von Hoff K, Hinkes B, Dannenmann-Stern E, von Bueren AO, Warmuth-Metz M, Soerensen N, et al. Frequency, risk-factors and survival of children with atypical teratoid rhabdoid tumors (AT/RT) of the CNS diagnosed between 1988 and 2004, and registered to the German HIT Database. Pediatr Blood Cancer 2011;57:978–85. [11] Wong T, Ho DM, Chang K, Yen S, Guo W, Chang F, et al. Primary pediatric brain tumors. Cancer 2005;104:2156–67.

rhabdoid tumor in the internal auditory canal.

The case of a thirteen-year-old woman showing an atypical teratoid/rhabdoid tumor (AT/RT) primarily occurred in the internal auditory canal was presen...
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