CHRONIC INFLAMMATORY LESION OF TEMPORAL BONE INVOLVING INNER EAR WITH MULTIPLE OCULAR MUSCLES PALSY
Introduction
Inflammatory pseudotumor (IPT) is an uncommon fibro-inflammatory lesion, also referred to as inflammatory myofibroblastic tumor, occurring most frequently in the lung, abdominal cavity, retroperitoneum, and extremities. Its occurrence in the head-and-neck region is less common.1 Temporal bone IPT is known to destruct adjacent bone structures and to invade the inner ear with or without cranial-nerve paralysis. We studied a case of temporal bone IPT extending to the petrous apex with multiple cranial-nerve paralysis.
Case report
A 52-year-old unmarried male was referred to our clinic with brain MR images, having complained of progressive diplopia for one month. On physical examination, a pinkish, pulsating middle-ear mass was found in his right ear. Left extra-ocular muscle (innervated by CN IV) and right extra-ocular muscle (CN VI) paralyses were confirmed by a specialized ophthalmologist (Fig. 1). A high-resolution temporal bone CT scan was
Fig. 1. Clinical features of a 52-year-old man with inflammatory pseudotumor of temporal bone. A: Oto-endoscopy of right eardrum showed pinkish pulsating mass. Abnormal eye movement of left IV and right VI extraocular muscles paralysis; B: Right gaze; C: Left gaze.
made to obtain additional information on bone destruction and extent of the disease. Infiltrative soft-tissue densities of the mastoid, middle ear, and petrous apex were found (Fig. 2,3). Our patient experienced sudden hearing loss in his right ear three years ago. Pure-tone audiometry and a vestibular-function test showed total deafness and canal paresis of the lesion side (Fig. 4). Subtotal petrosectomy with partial otic capsule removal was planned for diagnostic and curative purposes (Fig. 5).
Histopathology demonstrated massive mononuclear cell infiltration in the fibrocollagenous tissue without nuclear pleomorphism or mitosis (Fig. 6). Plasma cells were dominant among the chronic inflammatory cells and the immunohistochemistry did not show monoclonality. After the negative bacterial, fungal, and tuberculosis cultural report, high-dose oral steroids (methyl-prednisolone, mPd 60 mg/day) were applied for ten days and tapered to the maintaining dose of 5~10 mg per day.
The patient returned to the clinic at one, three, six, and 12 months after surgery. Diplopia had slowly improved and subsided at three months after surgery. Eye movement was completely normalized at the postoperative six-month evaluation. He still used a low dose of steroids (8 mg/d mPd) at the last follow-up visit.
Fig. 2. Temporal bone images. Infiltrative tumorous lesion involving inner ear (red arrows) and inflammatory lesion of the temporal bone; A: Post-gadolinium T1-weighted MR axial image; B: T2-weighted MR axial image; C: T2-weighted MR coronal image.
Discussion
There were not many reports of IPT involving the ear. Almost all reported cases involved temporal bone IPT with or without skull-base extension. Although two cases were confined to the middle ear, most cases involved mastoid and middle-ear cavity with local aggressiveness of neural and inner-ear destruction.2–4 There are controversies concerning the optimal treatment modality of IPT including surgery, radiotherapy and cor-ticosteroids.5 Surgery is primarily considered for many cases depending on tumor location and behavior. A high dose of oral steroid can be used solely or combined with surgical resection. Some lesions, such as orbital IPTs, showed a good response to primary radiotherapy, with up to 75% showing a reduction of mass.6 Tumors
Fig. 3. Temporal bone images. D: Axial; E: Coronal CT scan images. D, E: Computed tomography (CT) images of infiltrative soft tissue filled the middle-ear cavity and extended to petrous apex (orange arrows), erosion in medial wall of the internal auditory canal (yellow arrows), stapes and oval window destruction (white arrows), and internal carotid canal surrounded by the lesion (red arrow)
Fig. 4. Pure-tone audiometry and vestibular function test. A: Pure-tone audiometry showed total deafness of right ear; B: Bithermal caloric test revealed 94% weakness of the lesion side.
with a good response to corticosteroids are thought to be the most appropriate for radiotherapy. However, there are documented reports of local recurrence up to 15%, an incidence that can be reflecting inadequate resection of the lesion or tumors with behavior resembling inflammatory fibrosarcoma.7 Coffin et al. also showed that IPT can be a cause of death because of uncontrolled local growth.1 Temporal bone IPT in our case was clinically aggressive but was treated optimally with surgical excision with steroid maintenance therapy.
Fig. 5. Subtotal petrosectomy with partial otic capsule removal. A: Design for post-auricular incision line; B-1: Supralabyrinthine air cell tract exenteration was not sufficient for total removal of petrous apex lesion (orange arrow), translabyrinthine approach was conducted to remove the deeply seated petrous apex lesion (yellow lines); B-2: After removal of the middle-ear mass, the Eustachian tube orifice was obliterated with bone wax. Pseudocanal of tensor tympani m.(white arrow), internal carotid canal (yellow arrowhead); B-3: Destructed oval window was sealed with fat graft (orange loop); B-4: Fat graft obliteration of the opened vestibule (orange loop). All air cells and the mass around the vertical portion of the facial nerve (orange arrows) and the internal auditory canal (white arrows) were removed; C: Gross feature after subtotal removal of the mass; D: Obliteration of opened cavity with abdominal fat.
Fig. 6. Pathology of the middle-ear mass. Massive mononuclear inflammatory cell infiltration in the fibrocollagenous tissue without cellular atypism (A, H&E, ×100). Chronic inflammatory cells, mainly plasma cells (arrows, Russell bodies) are seen (B, H&E, ×200).
Conclusion
Temporal bone IPT often shows aggressive features with central neurological symptoms. Complete surgical excision should be considered first and steroids could be helpful for the suppression of the remnant disease progression.
References
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Address for correspondence: Kyu Hwan Jung, MD, Department of Otorhinolaryngology – Head and Neck Surgery, Haeundae Paik Hospital, Inje University College of Medicine, 1435, Jwa dong, Haeudae-gu, Busan, 612–030, Korea. kwmedi@gmail.com
Cholesteatoma and Ear Surgery – An Update, pp. 435–439
Edited by Haruo Takahashi
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