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Nasopharyngeal inflammatory pseudotumor showing abducens nerve palsy
Auris Nasus Larynx 38 (2011) 543–546 www.elsevier.com/locate/anl
Nasopharyngeal inflammatory pseudotumor showing abducens nerve palsy Kyu-Sup Cho a, Hak-Jin Kim b, Chang-Hun Lee c, Hwan-Jung Roh d,* a
Department of Otorhinolaryngology and Medical Research Institute, Pusan National University School of Medicine, Busan, South Korea b Department of Radiology, Pusan National University School of Medicine, Busan, South Korea c Department of Pathology, Pusan National University School of Medicine, Busan, South Korea d Department of Otorhinolaryngology, Pusan National University School of Medicine Yangsan Hospital, Yangsan, South Korea Received 2 October 2010; accepted 13 December 2010 Available online 12 January 2011
Abstract Inflammatory pseudotumor (IPT) originated from the nasopharynx is very rare. To the authors’ best knowledge, nasopharyngeal pseudotumor accompanied by abducens nerve palsy due to cavernous sinus invasion has not been reported previously. A 28-year-old male presented with abrupt-onset diplopia and right side severe headache. Physical examination revealed a mild contour bulging mass without mucosal ulceration or necrosis in the nasopharynx. The mass was thought to be a malignant neoplasm such as a carcinoma due to ill-defined, infiltrative tumor extended to the right parapharyngeal, carotid, prevertebral spaces and cavernous sinus on MR images, and hypermetabolic lesion on PET/CT. Histopathology demonstrated inflammatory pseudotumor. The patient was treated with high-dose of oral steroid, and then headache and diplopia was dramatically improved. Although IPT of the nasopharynx is very rare, it is important for otolaryngologists to be aware of this disease process. # 2011 Elsevier Ireland Ltd. All rights reserved. Keywords: Pseudotumor; Nasopharynx; Abducens nerve disease; Nasopharyngeal neoplasms; Cavernous sinus
1. Introduction Inflammatory pseudotumors (IPT) of the head and neck are idiopathic, inflammatory lesions of uncertain etiology that most commonly involve the orbit [1]. This reactive fibroinflammatory process can be locally aggressive and mimic malignancy and extranodal lymphoma. In addition to the orbit, other areas of involvement include the larynx [2], the paranasal sinuses [3], soft tissues of the neck and esophagus [4] and the skull base [5]. Similar lesions have been reported in other areas, such as lungs and heart [6,7]. However IPT originated from the nasopharynx is very rare and nasopharyngeal IPT accompanied by abducens nerve palsy due to cavernous sinus invasion has not previously * Corresponding author at: Department of Otorhinolaryngology, Pusan National University Yangsan Hospital, Beomeo-ri, Mul-geum eup, Yangsan Si, Gyeongsangnam-Do, 626-770, South Korea. Tel.: +82 55 360 1013, fax: +82 55 360 1027. E-mail address: [email protected] (H.-J. Roh).
been reported. We describe a case of nasopharyngeal pseudotumor involving the cavernous sinus misconceived nasopharyngeal carcinoma in patients who presented with severe headache and diplopia. 1.1. Case report A 28-year-old male with abrupt-onset diplopia and right side severe headache during medical treatment for right otitis media was referred to otorhinolaryngology clinic from other institution. The patient’s medical history was otherwise unremarkable. Neurologic examination revealed limitation of the extraocular muscles during right lateral gaze, with aggravated diplopia, suggesting right 6th cranial nerve palsy. Laboratory tests showed no significant abnormality. Physical examination revealed a mild contour bulging mass without mucosal ulceration or necrosis in the nasopharynx (Fig. 1A). His right tympanic membrane was amber and its mobility was decreased under the pneumatic
0385-8146/$ – see front matter # 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.anl.2010.12.005
544 [()TD$FIG]
K.-S. Cho et al. / Auris Nasus Larynx 38 (2011) 543–546
Fig. 1. Nasopharyngoscopy, MRI findings of right nasopharyngeal pseudotumor. (A) Nasopharyngoscopy reveals a mild contour bulging mass without mucosal ulceration or necrosis in the nasopharynx. (B) T2WI shows nasopharyngeal mass with intermediate signal intensity. The lesion is extended to the right parapharyngeal, carotid, prevertebral spaces and cavernous sinus. Right internal carotid artery was encircled and slightly narrowed by the mass. (C) Axial postcontrast-T1WI shows moderate enhancement of nasopharyngeal mass. (D) Coronal postcontrast-T1WI shows nasopharyngeal mass extending to lateral inferior portion of right cavernous sinus.
otoscopic examination. Puretone audiogram showed mild conductive hearing loss in his right ear. Tympanogram was B type in right ear and A type in left. MR images of the nasopharynx revealed a mass with an ill-defined margin and intermediate signal intensity on T1weighted images (T1WIs) and T2-weighted images (T2WIs) and moderate contrast enhancement on Gd-T1WIs (Fig. 1B– D). The mass extended to the right parapharyngeal, carotid, prevertebral spaces and cavernous sinus. Right internal carotid artery was encircled and slightly narrowed by the mass. Left prevertebral muscles were also involved with the
[()TD$FIG]
mass. Right middle ear cavity and mastoid showed hypointensity on T1WIs, hyperintensity on T2WIs and no contrast enhancement. Bone marrow or cortex of the skull base was not changed on MR images. There was no evidence of bone destruction adjacent the mass on temporal bone CT scan. A PET/CT revealed a hypermetabolic lesion (max SUV 7.9) in the right side nasopharynx extending into the right parapharyngeal space, retropharyngeal space and preclival area without any metastasis. Transnasal endoscopic biopsy under local anesthesia was performed. After local injection, nasopharyngeal mucosa was incised with sickle knife and then deep biopsy in the preclival tissue and superficial biopsy in the posterior wall of the nasopharynx was done. Histopathology showed diffuse infiltration of lymphoplasma cells with the formation of reactive lymphoid follicle (Fig. 2A). Immunohistochemical staining for CD3 (pan T cell marker) and CD20 (pan B cell marker) revealed that the lymphoid cells showed polyclonal reactive pattern. These findings were consistent with IPT (Fig. 2B and C). The patient was treated with high-dose of oral steroid with prednisolone initially. The initial daily dosages were 60 mg. Initial dosages were maintained for 2 weeks and tapered to 40 mg and 20 mg respectively for 2 weeks. Low-dose steroid maintenance therapy taking less than 10 mg of prednisolone daily was continued for 12 weeks. Headache was dramatically improved and 6th cranial nerve palsy showed marked improvement during steroid therapy. He has continued to do well and follow-up MR image at 6 months after steroid treatment revealed no evidence of recurrence (Fig. 3). 2. Discussion IPT is a rare benign lesion characterized by a collection of acute and chronic inflammatory cells with variable fibrous response. Although the lung is the best known and most common site, the IPT occurs in diverse extrapulmonary locations [8]. IPT in the head and neck account for less than 5% of all cases and most commonly involves the orbit. Although non-orbital pseudotumor of the head and neck has been reported in other areas, nasopharyngeal pseudotumor
Fig. 2. Histopathologic findings of nasopharyngeal pseudotumor. (A) Microscopic finding shows diffuse infiltration of lymphocytes with formation of subepithelial lymphoid follicles ($) and underlying stromal fibrosis (H & E, 200). Immunohistochemical stains for pan T cell marker CD 3 (B) and pan B cell marker CD 20 (C) reveals reactive pattern (200).
[()TD$FIG]
K.-S. Cho et al. / Auris Nasus Larynx 38 (2011) 543–546
545
Fig. 3. Follow-up MRI at 6 months after steroid treatment. T2WI (A) and postcontrast-T1WI (B) show nearly normalized previous abnormal right nasopharyngeal wall after steroid therapy. Narrowing of the right internal carotid artery was reduced. Right otomastoiditis was also improved.
invading the cavernous sinus is exceedingly rare. The etiology and pathogenesis of IPT are unknown. Clinical presentation varies with location of the tumor. Patients can present with headache, hearing loss, dizziness, and/or cranial nerve palsies [9]. Diagnosis is one of exclusion as these lesions can mimic malignancy with bone erosion and cranial nerve involvement. In this case, the tumor was at first thought to be a malignant neoplasm such as a nasopharyngeal lymphoma or carcinoma due to rarity of nasopharyngeal pseudotumor, illdefined, infiltrative tumor on MR images, 6th cranial nerve palsy, and hypermetabolic lesion on PET/CT. The distinction between pseudotumor and malignant neoplasm is very difficult without biopsy. But characteristic MR features can be helpful in differential diagnosis from malignant neoplasm. Although nasopharyngeal carcinomas usually show iso- to hyperintense signal intensity on T2WIs and heterogenous enhancement, nasopharyngeal lymphomas show sharply margined homogenous tumor with moderate signal intensity in both T1WI and T2WI and mild or moderate homogenous enhancement [10]. A large tumor that fills the nasopharynx, with no or minimal invasion into deep structures, and a propensity to extend down into tonsil, rather than up into the skull base, may suggest the diagnosis of lymphoma over nasopharyngeal carcinoma [11]. However IPT reveals ill-defined, less-likely contour bulging features with local infiltration, hypointensity or isointensity on T2WIs, relatively weak enhancement, no significant regional lymphadenopathy [12]. These findings were also noted in this patient who had ill-defined tumor that was isointense to brain on both T1 and T2 images. And also bone destruction is a sensitive finding of malignant mass, however was not evident in the present case. Treatment varies with location of the tumor, degree of local invasion, and the possibility of complete resection. The administration of high-dose corticosteroid is the primary treatment of choice. Treatment is usually with steroids (prednisolone) given as 1 mg/kg/d for 14 days, followed by a taper [9,13]. Although orbital pseudotumors are fairly
responsive to steroid therapy, 17–52% of these patients have some type of recurrence requiring prolonged steroid therapy. This trend may be even greater for non-orbital pseudotumor sites. In our case, patient has taken oral prednisolone during 4 months for prevention of relapse. However if the response to steroid is poor, complete surgical resection is advocated [4]. When such resection is not possible, local radiation therapy has been shown to be effective in some cases [5]. Although IPT of the nasopharynx is very rare, it is important for otolaryngologists to be aware of this disease process. Where a mild contour bulging nasopharyngeal mass showing heterogenous low or intermediate signal intensity at T2WIs, has an infiltrative appearance in the presence of an apparently normal pharyngeal mucosa, and there is no known underlying malignancy and adjacent bone destruction, IPT should be included in the differential diagnosis.
References [1] Batsakis JG, el-Naggar AK, Luna MA, Goepfert H. Inflammatory pseudotumor: what is it? How does it behave? Ann Otol Rhinol Laryngol 1995;104:329–31. [2] Zitsch 3rd RP, Pollak N, Loy TS. Management of inflammatory pseudotumor of the larynx. Otolaryngol Head Neck Surg 2007; 136:139–41. [3] Lee HM, Choi G, Choi CS, Kim CH, Lee SH. Inflammatory pseudotumor of the maxillary sinus. Otolaryngol Head Neck Surg 2001;125:565–6. [4] Ceruse P, Ramade A, Vautrin R, Crozes C, Dubreuil C, Disant F. Inflammatory pseudotumor of the neck: a long-term result without surgical approach. Otolaryngol Head Neck Surg 2005;132:812–3. [5] Lee DK, Cho YS, Hong SH, Chung WH, Ahn YC. Inflammatory pseudotumor involving the skull base: response to steroid and radiation therapy. Otolaryngol Head Neck Surg 2006;135:144–8. [6] Yano Y, Mori M, Kagami S, Fushitani K, Sugano T, Namba Y, et al. Inflammatory pseudotumor of the lung with rapid growth. Intern Med 2009;48:1279–82. [7] Adler A, Fimbres A, Marcinak J, Johnson A, Zheng X, Hasegawa. et al. Inflammatory pseudotumor of the heart caused by Listeria monocytogenes infection. J Infect 2009;58:161–3. [8] Coffin CM, Watterson J, Priest JR, Dehner LP. Extrapulmonary inflammatory myofibroblastic tumor (inflammatory pseudotumor).
546
K.-S. Cho et al. / Auris Nasus Larynx 38 (2011) 543–546
A clinicopathologic and immunohistochemical study of 84 cases. Am J Surg Pathol 1995;19:859–72. [9] Cho YS, Kim SM, Chung WH, Hong SH. Inflammatory pseudotumor involving the skull base and cervical spine. J Laryngol Otol 2001;115:580–4. [10] King AD, Lam WW, Leung SF, Chan YL, Teo P, Metreweli C. MRI of local disease in nasopharyngeal carcinoma: tumour extent vs tumour stage. Br J Radiol 1999;72:734–41.
[11] King AD, Lei KI, Richards PS, Ahuja AT. Non-Hodgkin’s lymphoma of the nasopharynx: CT and MR imaging. Clin Radiol 2003;58: 621–5. [12] Choi SY, Yu IK, Han MH, Lee BH, Song CJ, Kim KS. Fibrosing inflammatory pseudotumor of the nasopharynx: MR features and histopathologic correlation. Eur J Radiol 2009;72:274–7. [13] Williamson RA, Paueksakon P, Coker NJ. Inflammatory pseudotumor of the temporal bone. Otol Neurotol 2003;24:818–22.
Nasopharyngeal inflammatory pseudotumor showing abducens nerve palsy Kyu-Sup Cho a, Hak-Jin Kim b, Chang-Hun Lee c, Hwan-Jung Roh d,* a
Department of Otorhinolaryngology and Medical Research Institute, Pusan National University School of Medicine, Busan, South Korea b Department of Radiology, Pusan National University School of Medicine, Busan, South Korea c Department of Pathology, Pusan National University School of Medicine, Busan, South Korea d Department of Otorhinolaryngology, Pusan National University School of Medicine Yangsan Hospital, Yangsan, South Korea Received 2 October 2010; accepted 13 December 2010 Available online 12 January 2011
Abstract Inflammatory pseudotumor (IPT) originated from the nasopharynx is very rare. To the authors’ best knowledge, nasopharyngeal pseudotumor accompanied by abducens nerve palsy due to cavernous sinus invasion has not been reported previously. A 28-year-old male presented with abrupt-onset diplopia and right side severe headache. Physical examination revealed a mild contour bulging mass without mucosal ulceration or necrosis in the nasopharynx. The mass was thought to be a malignant neoplasm such as a carcinoma due to ill-defined, infiltrative tumor extended to the right parapharyngeal, carotid, prevertebral spaces and cavernous sinus on MR images, and hypermetabolic lesion on PET/CT. Histopathology demonstrated inflammatory pseudotumor. The patient was treated with high-dose of oral steroid, and then headache and diplopia was dramatically improved. Although IPT of the nasopharynx is very rare, it is important for otolaryngologists to be aware of this disease process. # 2011 Elsevier Ireland Ltd. All rights reserved. Keywords: Pseudotumor; Nasopharynx; Abducens nerve disease; Nasopharyngeal neoplasms; Cavernous sinus
1. Introduction Inflammatory pseudotumors (IPT) of the head and neck are idiopathic, inflammatory lesions of uncertain etiology that most commonly involve the orbit [1]. This reactive fibroinflammatory process can be locally aggressive and mimic malignancy and extranodal lymphoma. In addition to the orbit, other areas of involvement include the larynx [2], the paranasal sinuses [3], soft tissues of the neck and esophagus [4] and the skull base [5]. Similar lesions have been reported in other areas, such as lungs and heart [6,7]. However IPT originated from the nasopharynx is very rare and nasopharyngeal IPT accompanied by abducens nerve palsy due to cavernous sinus invasion has not previously * Corresponding author at: Department of Otorhinolaryngology, Pusan National University Yangsan Hospital, Beomeo-ri, Mul-geum eup, Yangsan Si, Gyeongsangnam-Do, 626-770, South Korea. Tel.: +82 55 360 1013, fax: +82 55 360 1027. E-mail address: [email protected] (H.-J. Roh).
been reported. We describe a case of nasopharyngeal pseudotumor involving the cavernous sinus misconceived nasopharyngeal carcinoma in patients who presented with severe headache and diplopia. 1.1. Case report A 28-year-old male with abrupt-onset diplopia and right side severe headache during medical treatment for right otitis media was referred to otorhinolaryngology clinic from other institution. The patient’s medical history was otherwise unremarkable. Neurologic examination revealed limitation of the extraocular muscles during right lateral gaze, with aggravated diplopia, suggesting right 6th cranial nerve palsy. Laboratory tests showed no significant abnormality. Physical examination revealed a mild contour bulging mass without mucosal ulceration or necrosis in the nasopharynx (Fig. 1A). His right tympanic membrane was amber and its mobility was decreased under the pneumatic
0385-8146/$ – see front matter # 2011 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.anl.2010.12.005
544 [()TD$FIG]
K.-S. Cho et al. / Auris Nasus Larynx 38 (2011) 543–546
Fig. 1. Nasopharyngoscopy, MRI findings of right nasopharyngeal pseudotumor. (A) Nasopharyngoscopy reveals a mild contour bulging mass without mucosal ulceration or necrosis in the nasopharynx. (B) T2WI shows nasopharyngeal mass with intermediate signal intensity. The lesion is extended to the right parapharyngeal, carotid, prevertebral spaces and cavernous sinus. Right internal carotid artery was encircled and slightly narrowed by the mass. (C) Axial postcontrast-T1WI shows moderate enhancement of nasopharyngeal mass. (D) Coronal postcontrast-T1WI shows nasopharyngeal mass extending to lateral inferior portion of right cavernous sinus.
otoscopic examination. Puretone audiogram showed mild conductive hearing loss in his right ear. Tympanogram was B type in right ear and A type in left. MR images of the nasopharynx revealed a mass with an ill-defined margin and intermediate signal intensity on T1weighted images (T1WIs) and T2-weighted images (T2WIs) and moderate contrast enhancement on Gd-T1WIs (Fig. 1B– D). The mass extended to the right parapharyngeal, carotid, prevertebral spaces and cavernous sinus. Right internal carotid artery was encircled and slightly narrowed by the mass. Left prevertebral muscles were also involved with the
[()TD$FIG]
mass. Right middle ear cavity and mastoid showed hypointensity on T1WIs, hyperintensity on T2WIs and no contrast enhancement. Bone marrow or cortex of the skull base was not changed on MR images. There was no evidence of bone destruction adjacent the mass on temporal bone CT scan. A PET/CT revealed a hypermetabolic lesion (max SUV 7.9) in the right side nasopharynx extending into the right parapharyngeal space, retropharyngeal space and preclival area without any metastasis. Transnasal endoscopic biopsy under local anesthesia was performed. After local injection, nasopharyngeal mucosa was incised with sickle knife and then deep biopsy in the preclival tissue and superficial biopsy in the posterior wall of the nasopharynx was done. Histopathology showed diffuse infiltration of lymphoplasma cells with the formation of reactive lymphoid follicle (Fig. 2A). Immunohistochemical staining for CD3 (pan T cell marker) and CD20 (pan B cell marker) revealed that the lymphoid cells showed polyclonal reactive pattern. These findings were consistent with IPT (Fig. 2B and C). The patient was treated with high-dose of oral steroid with prednisolone initially. The initial daily dosages were 60 mg. Initial dosages were maintained for 2 weeks and tapered to 40 mg and 20 mg respectively for 2 weeks. Low-dose steroid maintenance therapy taking less than 10 mg of prednisolone daily was continued for 12 weeks. Headache was dramatically improved and 6th cranial nerve palsy showed marked improvement during steroid therapy. He has continued to do well and follow-up MR image at 6 months after steroid treatment revealed no evidence of recurrence (Fig. 3). 2. Discussion IPT is a rare benign lesion characterized by a collection of acute and chronic inflammatory cells with variable fibrous response. Although the lung is the best known and most common site, the IPT occurs in diverse extrapulmonary locations [8]. IPT in the head and neck account for less than 5% of all cases and most commonly involves the orbit. Although non-orbital pseudotumor of the head and neck has been reported in other areas, nasopharyngeal pseudotumor
Fig. 2. Histopathologic findings of nasopharyngeal pseudotumor. (A) Microscopic finding shows diffuse infiltration of lymphocytes with formation of subepithelial lymphoid follicles ($) and underlying stromal fibrosis (H & E, 200). Immunohistochemical stains for pan T cell marker CD 3 (B) and pan B cell marker CD 20 (C) reveals reactive pattern (200).
[()TD$FIG]
K.-S. Cho et al. / Auris Nasus Larynx 38 (2011) 543–546
545
Fig. 3. Follow-up MRI at 6 months after steroid treatment. T2WI (A) and postcontrast-T1WI (B) show nearly normalized previous abnormal right nasopharyngeal wall after steroid therapy. Narrowing of the right internal carotid artery was reduced. Right otomastoiditis was also improved.
invading the cavernous sinus is exceedingly rare. The etiology and pathogenesis of IPT are unknown. Clinical presentation varies with location of the tumor. Patients can present with headache, hearing loss, dizziness, and/or cranial nerve palsies [9]. Diagnosis is one of exclusion as these lesions can mimic malignancy with bone erosion and cranial nerve involvement. In this case, the tumor was at first thought to be a malignant neoplasm such as a nasopharyngeal lymphoma or carcinoma due to rarity of nasopharyngeal pseudotumor, illdefined, infiltrative tumor on MR images, 6th cranial nerve palsy, and hypermetabolic lesion on PET/CT. The distinction between pseudotumor and malignant neoplasm is very difficult without biopsy. But characteristic MR features can be helpful in differential diagnosis from malignant neoplasm. Although nasopharyngeal carcinomas usually show iso- to hyperintense signal intensity on T2WIs and heterogenous enhancement, nasopharyngeal lymphomas show sharply margined homogenous tumor with moderate signal intensity in both T1WI and T2WI and mild or moderate homogenous enhancement [10]. A large tumor that fills the nasopharynx, with no or minimal invasion into deep structures, and a propensity to extend down into tonsil, rather than up into the skull base, may suggest the diagnosis of lymphoma over nasopharyngeal carcinoma [11]. However IPT reveals ill-defined, less-likely contour bulging features with local infiltration, hypointensity or isointensity on T2WIs, relatively weak enhancement, no significant regional lymphadenopathy [12]. These findings were also noted in this patient who had ill-defined tumor that was isointense to brain on both T1 and T2 images. And also bone destruction is a sensitive finding of malignant mass, however was not evident in the present case. Treatment varies with location of the tumor, degree of local invasion, and the possibility of complete resection. The administration of high-dose corticosteroid is the primary treatment of choice. Treatment is usually with steroids (prednisolone) given as 1 mg/kg/d for 14 days, followed by a taper [9,13]. Although orbital pseudotumors are fairly
responsive to steroid therapy, 17–52% of these patients have some type of recurrence requiring prolonged steroid therapy. This trend may be even greater for non-orbital pseudotumor sites. In our case, patient has taken oral prednisolone during 4 months for prevention of relapse. However if the response to steroid is poor, complete surgical resection is advocated [4]. When such resection is not possible, local radiation therapy has been shown to be effective in some cases [5]. Although IPT of the nasopharynx is very rare, it is important for otolaryngologists to be aware of this disease process. Where a mild contour bulging nasopharyngeal mass showing heterogenous low or intermediate signal intensity at T2WIs, has an infiltrative appearance in the presence of an apparently normal pharyngeal mucosa, and there is no known underlying malignancy and adjacent bone destruction, IPT should be included in the differential diagnosis.
References [1] Batsakis JG, el-Naggar AK, Luna MA, Goepfert H. Inflammatory pseudotumor: what is it? How does it behave? Ann Otol Rhinol Laryngol 1995;104:329–31. [2] Zitsch 3rd RP, Pollak N, Loy TS. Management of inflammatory pseudotumor of the larynx. Otolaryngol Head Neck Surg 2007; 136:139–41. [3] Lee HM, Choi G, Choi CS, Kim CH, Lee SH. Inflammatory pseudotumor of the maxillary sinus. Otolaryngol Head Neck Surg 2001;125:565–6. [4] Ceruse P, Ramade A, Vautrin R, Crozes C, Dubreuil C, Disant F. Inflammatory pseudotumor of the neck: a long-term result without surgical approach. Otolaryngol Head Neck Surg 2005;132:812–3. [5] Lee DK, Cho YS, Hong SH, Chung WH, Ahn YC. Inflammatory pseudotumor involving the skull base: response to steroid and radiation therapy. Otolaryngol Head Neck Surg 2006;135:144–8. [6] Yano Y, Mori M, Kagami S, Fushitani K, Sugano T, Namba Y, et al. Inflammatory pseudotumor of the lung with rapid growth. Intern Med 2009;48:1279–82. [7] Adler A, Fimbres A, Marcinak J, Johnson A, Zheng X, Hasegawa. et al. Inflammatory pseudotumor of the heart caused by Listeria monocytogenes infection. J Infect 2009;58:161–3. [8] Coffin CM, Watterson J, Priest JR, Dehner LP. Extrapulmonary inflammatory myofibroblastic tumor (inflammatory pseudotumor).
546
K.-S. Cho et al. / Auris Nasus Larynx 38 (2011) 543–546
A clinicopathologic and immunohistochemical study of 84 cases. Am J Surg Pathol 1995;19:859–72. [9] Cho YS, Kim SM, Chung WH, Hong SH. Inflammatory pseudotumor involving the skull base and cervical spine. J Laryngol Otol 2001;115:580–4. [10] King AD, Lam WW, Leung SF, Chan YL, Teo P, Metreweli C. MRI of local disease in nasopharyngeal carcinoma: tumour extent vs tumour stage. Br J Radiol 1999;72:734–41.
[11] King AD, Lei KI, Richards PS, Ahuja AT. Non-Hodgkin’s lymphoma of the nasopharynx: CT and MR imaging. Clin Radiol 2003;58: 621–5. [12] Choi SY, Yu IK, Han MH, Lee BH, Song CJ, Kim KS. Fibrosing inflammatory pseudotumor of the nasopharynx: MR features and histopathologic correlation. Eur J Radiol 2009;72:274–7. [13] Williamson RA, Paueksakon P, Coker NJ. Inflammatory pseudotumor of the temporal bone. Otol Neurotol 2003;24:818–22.