Inflammatory Myofibroblastic Tumor of the Larynx—A Case Report *Bao Anh Do, †Rickul Varshney, †,‡Faisal Zawawi, §Mark Levental, kDerin Caglar, and †Jonathan Young, *yxkMontreal, Quebec, Canada, and zJeddah, Saudi Arabia
Summary: Objectives. Inflammatory myofibroblastic tumor (IMT) is a borderline neoplasm with uncertain malignant potential. It is a rare disease also referred to as an inflammatory pseudotumor, a plasma cell granuloma, and an inflammatory fibrosarcoma. IMT rarely also involves the head and neck region with only 50 cases of laryngeal IMT reported in the literature, and this is the first case with reported magnetic resonance imaging (MRI) findings. Methods. A 37-year-old man with a 1-year history of hoarseness, dysphagia, and fatigue presented with a right vocal fold submucosal mass and was treated conservatively. Results. The MRI of the neck revealed a mildly spontaneously hyperintense right true vocal fold on GRE images and relative hyperintensity on fat-saturation T2-weighted images. A biopsy of the right-sided submucosal laryngeal mass was performed and the pathologic examination revealed a lesion consistent with an IMT. Conclusion. IMT is a borderline neoplasm with uncertain malignant potential. There are many variants of IMT and its etiology is not truly understood. In general, IMT of the larynx has a benign clinical course with low rates of recurrence. Key Words: Laryngology–Inflammatory myofibroblastic tumor–Vocal fold tumor–Larynx.
INTRODUCTION Inflammatory myofibroblastic tumor (IMT) is a rare borderline neoplasm with uncertain behavior. It is also known as inflammatory pseudotumor, plasma cell granuloma, and sometimes referred as inflammatory fibrosarcoma with each having some variants reported in the literature.1 IMT mainly affects the lungs, the mesentery, and the omentum. Rarely does it affect the head and neck region. To date and to the author’s knowledge, less than 50 cases of IMT of the larynx have been reported in the English literature. In this article, a case of a 37-year-old man with IMT of the larynx is presented and a discussion on the clinical presentation of IMT, the histopathology, as well as the management will follow. CASE REPORT The presentation A 37-year-old man was seen in our Otolaryngology clinic with a 1-year history of hoarseness, dysphagia, and fatigue. He was a nonsmoker and did not drink alcohol. He was known for a vitamin B12 deficiency and gastro-oesophageal reflux. His hoarseness was rough, effortful with fatigue. He did not have difficulty eating or drinking but described an increasingly cumbersome swallow during meals. At that time, he was also being investigated for left-sided body weakness. His general head and neck examination was normal. Flexible transnasal Accepted for publication September 17, 2013. Consent was obtained by the patient after consultation with our hospitals Research Ethics Committee and thus formal institutional review board was not required. From the *Faculty of Medicine, McGill University, Montreal, Quebec, Canada; yDepartment of Otorhinolaryngology-Head and Neck Surgery, McGill University, Montreal, Quebec, Canada; zDepartment of Otolaryngology, King Abdulaziz University, Jeddah, Saudi Arabia; xDepartment of Diagnostic Radiology, McGill University, Montreal, Quebec, Canada; and the kDepartment of Pathology, McGill University, Montreal, Quebec, Canada. Address correspondence and reprint requests to Bao Anh Do, 8607 Foucher, Montreal, Quebec, Canada H2P 2C3. E-mail: [email protected] Journal of Voice, Vol. 28, No. 2, pp. 258-261 0892-1997/$36.00 Ó 2014 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2013.09.004
pharyngolaryngoscopy revealed a right vocal fold submucosal mass, with generalized thickening along the entire length of the fold (Figure 1). The fold did exhibit normal mobility. The mucosal wave was absent on the right fold and diminished anteriorly on the left fold due to the bulkiness of the lesion. Mild signs of laryngopharyngeal reflux were also present. Radiology. The magnetic resonance imaging (MRI) of the neck revealed a mildly spontaneously hyperintense right true vocal fold on fat saturated T1 gradient-echo (GRE) images and relative hyperintensity on fat-saturation T2-weighted images (Figures 2–5). It demonstrated strong enhancement following contrast infusion. The thickening of the right true vocal fold extended to the region of the anterior commissure but did not cross it. There was bulging of the fold into the subglottic space, but there was no true extension. The barium swallow and the modified barium swallow were unremarkable. Surgery. Suspension microlaryngoscopy and cold steel biopsy of the right-sided submucosal laryngeal mass was performed. A lateral microflap was performed and a submucosal plane was lifted. The mass was extremely rigid, most comparable with wood consistency. During the debridement, the surgeon took great care not to harm the mucosa overlying the lesion. Pathology Biopsies of the mass showed a low-grade myofibroblastic tumor without marked atypia, necrosis, or mitoses admixed with lymphocytes and plasma cells (Figure 6). There was no evidence of definite malignancy. The immunochemistry stains were positive for smooth muscle actin (SMA), desmin, and CD34. They were negative for CKAE1/AE3, myogenin, caldesmon, beta-catenin, S100, and anaplastic lymphoma kinase (ALK) protein. ALK protein fluorescence in situ hybridization was also negative. Moreover, the Ki67 proliferative index was low. Management Postoperatively, the patient was reviewed in our institutional tumor board conference. The team agreed for a conservative
Bao Anh Do, et al
Report on IMT of Larynx
FIGURE 1. Flexible transnasal pharyngolaryngoscopy revealing a right vocal fold submucosal mass with generalized thickening of the entire length of the fold. approach, which included laser debulking in the event of voice or airway compromise with close observation with serial MRI. There was a slight increase of the mass at a follow-up appointment clinically a few months postoperatively, without fear of airway obstruction. A trial of oral steroids for 4 weeks was initiated. Fifty milligrams of prednisone were given daily for 1 week, and the doses were tapered over the next 3 weeks. This resulted in a significant reduction in the tumor size. Currently, the patient is stable for 6 months, has a voice quality that is manageable, and a patent airway. DISCUSSION IMT is classified as a borderline neoplasm with uncertain behavior. Although, IMT of the head and neck is rare, the larynx is the most common site in the latter.2,3
FIGURE 2. MRI Coronal T1W postcontrast showing the thickening of the right true vocal fold.
259
FIGURE 3. MRI GRE precontrast of the true vocal folds. The etiology of IMT is still unclear. It was first thought to be of inflammatory origin; however, researchers refuted this hypothesis by finding clonal cytogenetic aberrations that would explain the behavior of this tumor.4 From the literature, common factors predisposing to IMT, such as trauma, smoking, and immune responses, have been proposed.5 The mean age of patients with IMT is around 43 years. They most often present to the clinic with hoarseness or dysphonia. Other symptoms that are occasionally present in this disease are dyspnea, stridor, globus, dysphagia, hemoptysis, cough, and otalgia.5 A small portion of patients with IMT can also have a syndrome of fever, weight loss, growth failure, malaise, anemia, thrombocytosis, polyclonal hyperglobulinemia, and elevated erythrocyte sedimentation rate, but these have not been documented in laryngeal IMT cases.4 IMT of the larynx is most often localized in the vocal folds, in the subglottis, or in the aryepiglottic folds.5 Our presentation of the IMT was particular on imaging. The use of MRI has not been reported in cases of laryngeal IMT. The
FIGURE 4. MRI GRE postcontrast of the true vocal folds.
260
Journal of Voice, Vol. 28, No. 2, 2014
FIGURE 6. Magnification (310) of hematoxylin- and eosin-stained IMT.
FIGURE 5. MRI fat saturation T2-weighted image of the true vocal folds.
thickening of the true vocal fold without extension is unique to our knowledge. Ni et al6 reported a case describing the findings on computed tomography imaging which showed uneven enhancement of the epiglottic-glossal surface. While Biron et al5 demonstrated a mass in the right subglottis that was not invading the laryngeal skeleton. These variations in radiological findings support the uncertain behavior of laryngeal IMT. Moreover, by looking into other locations of IMT, MRI findings that were reported also showed differences. In cases of paranasal sinuses IMT, one of the MRI revealed a nonhomogeneous and intermediate signal regardless of the sequence used.7 On another one, the mass was isointense on T1-weighted images and hypointense on T2-weighted images and was homogenously enhanced. In all these cases, MRI by itself is not diagnostic.8 IMT is a neoplasm composed of varying degrees of myofibroblastic spindle cells and inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils.9,10 They are positive for SMA, desmin, and vimentin. In laryngeal IMT, ALK1 immunochemistry staining is usually positive although not universal.4,6,11 In our case, the lesion was diagnosed as an IMT because of its strong inflammatory component in addition to the tumor’s response to systemic steroids. A previous study looked at the outcomes in association with ALK1-reactivity and showed that ALK1-negativity seemed to be associated with metastasis, whereas ALK1-positivity was associated with recurrence.4 However, laryngeal IMT was not studied on those researches. Moreover, no cases of metastasis in laryngeal IMT have been reported up to now.6 The use of ALK FISH is not universal. In our case, the FISH was done in addition to the ALK immunochemistry for research purposes. None of the laryngeal IMT cases reported in the literature mentioned the FISH but only commented on ALK-1 immunochemistry staining. Coffin et al4 studied the ALK expression in IMT. They reported the correlation of ALK-1 reactivity on immunochemistry staining with the ALK FISH which supports our finding.
In the literature, the therapeutic approach varied from medical treatment with steroids, chemotherapy, or radiotherapy to surgical treatment with local excision with laser or cold dissection and even laryngectomy.5 Only a minority of reports observed local recurrence of disease and this was in association with surgically excised tumors. There was no reported recurrence in cases treated with systemic steroids. In this report, the size of the lesion was the limiting factor to an adequate excision. Although the tumor was sparing the cricoarytenoid joint, the tumor was surrounding it. The only way to adequately excise this lesion was to perform a hemilaryngectomy. Given the airway stability and quality of voice, this procedure was deemed to be too aggressive in presented clinical settings. Observation with serial laser debulking for airway or voice improvement much like in amyloidosis was agreed upon. CONCLUSION Briefly, there are many variants of IMT and its etiology is not fully understood. In general, IMT of the larynx has a benign clinical course with low rate of recurrence. There is no consensus on treatment with most proposing a conservative approach with local excision with possible adjuvant medical treatment such as steroids. Finally, it is imperative and necessary to have information in the literature about MRI findings in these cases and how do they compare with other cases of IMT in the head and neck region. This would help readers understand the disease further and keep such a relatively uncommon diagnosis in mind while managing challenging cases. REFERENCES 1. Coffin CM, Fletcher CDM. Inflammatory myofibroblastic tumour. In: Fletcher CDM, Unni KK, Mertens F, eds. WHO Classification of Tumors: Pathology and Genetics of Tumors of Soft Tissue and Bone. Lyon, France: IARC Press; 2002:91–94. 2. Wenig BM, Devaney K, Bisceglia M. Inflammatory myofibroblastic tumor of the larynx: a clinicopathologic study of eight cases simulating a malignant spindle cell neoplasm. Cancer. 1995;76:2217–2229. 3. Idrees MT, Huan Y, Woo P, et al. Inflammatory myofibroblastic tumor of larynx: a benign lesion with variable morphological spectrum. Ann Diagn Pathol. 2007;11:433–439.
Bao Anh Do, et al
Report on IMT of Larynx
4. Coffin CM, Hornick JL, Fletcher CD. Inflammatory myofibroblastic tumor: comparison of clinicopathologic, histologic, and immunohistochemical features including ALK expression in atypical and aggressive cases. Am J Surg Pathol. 2007;31:509–520. 5. Biron VL, Waghray R, Medlicott SA, Bosch JD. Inflammatorypseudotumours of the larynx: three cases and a review of the literature. J Otolaryngol Head Neck Surg. 2008;37:E32–E38. 6. Ni C, Xu YY, Zhou SH, Wang SQ. Differential diagnosis of inflammatory myofibroblastic tumour and low-grade myofibroblastic sarcoma: two case reports with a literature review. J Int Med Res. 2011;39:311–320. 7. Ushio M, Takeuchi N, Kikuchi S, Kaga K. Inflammatory pseudotumour of the paranasal sinuses—a case report. Auris Nasus Larynx. 2007;34: 533–536.
261 8. Inoue A, Egami N, Kitahara N, Yagi M. Differential diagnosis of proptosis: report of 2 cases. Auris Nasus Larynx. 2010;37:526–529. 9. Coffin CM, Watterson J, Priest JR, Dehner LP. Extrapulmonary inflammatory myofibroblastic tumor (inflammatory pseudotumor). A clinicopathologic and immunohistochemical study of 84 cases. Am J Surg Pathol. 1995;19:859–872. 10. Brcic I, Brcic L, Hutinec Z, Prgomet D, Seiwerth S. Laryngeal inflammatory myofibroblastic tumor in a man: a case report. Coll Antropol. 2010;34: 1127–1129. 11. V€olker HU, Scheich M, H€oller S, Str€obel P, Hagen R, M€ullerHermelink HK, Eck M. Differential diagnosis of laryngeal spindle cell carcinoma and inflammatory myofibroblastic tumor—report of two cases with similar morphology. Diagn Pathol. 2007;2:1.
Summary: Objectives. Inflammatory myofibroblastic tumor (IMT) is a borderline neoplasm with uncertain malignant potential. It is a rare disease also referred to as an inflammatory pseudotumor, a plasma cell granuloma, and an inflammatory fibrosarcoma. IMT rarely also involves the head and neck region with only 50 cases of laryngeal IMT reported in the literature, and this is the first case with reported magnetic resonance imaging (MRI) findings. Methods. A 37-year-old man with a 1-year history of hoarseness, dysphagia, and fatigue presented with a right vocal fold submucosal mass and was treated conservatively. Results. The MRI of the neck revealed a mildly spontaneously hyperintense right true vocal fold on GRE images and relative hyperintensity on fat-saturation T2-weighted images. A biopsy of the right-sided submucosal laryngeal mass was performed and the pathologic examination revealed a lesion consistent with an IMT. Conclusion. IMT is a borderline neoplasm with uncertain malignant potential. There are many variants of IMT and its etiology is not truly understood. In general, IMT of the larynx has a benign clinical course with low rates of recurrence. Key Words: Laryngology–Inflammatory myofibroblastic tumor–Vocal fold tumor–Larynx.
INTRODUCTION Inflammatory myofibroblastic tumor (IMT) is a rare borderline neoplasm with uncertain behavior. It is also known as inflammatory pseudotumor, plasma cell granuloma, and sometimes referred as inflammatory fibrosarcoma with each having some variants reported in the literature.1 IMT mainly affects the lungs, the mesentery, and the omentum. Rarely does it affect the head and neck region. To date and to the author’s knowledge, less than 50 cases of IMT of the larynx have been reported in the English literature. In this article, a case of a 37-year-old man with IMT of the larynx is presented and a discussion on the clinical presentation of IMT, the histopathology, as well as the management will follow. CASE REPORT The presentation A 37-year-old man was seen in our Otolaryngology clinic with a 1-year history of hoarseness, dysphagia, and fatigue. He was a nonsmoker and did not drink alcohol. He was known for a vitamin B12 deficiency and gastro-oesophageal reflux. His hoarseness was rough, effortful with fatigue. He did not have difficulty eating or drinking but described an increasingly cumbersome swallow during meals. At that time, he was also being investigated for left-sided body weakness. His general head and neck examination was normal. Flexible transnasal Accepted for publication September 17, 2013. Consent was obtained by the patient after consultation with our hospitals Research Ethics Committee and thus formal institutional review board was not required. From the *Faculty of Medicine, McGill University, Montreal, Quebec, Canada; yDepartment of Otorhinolaryngology-Head and Neck Surgery, McGill University, Montreal, Quebec, Canada; zDepartment of Otolaryngology, King Abdulaziz University, Jeddah, Saudi Arabia; xDepartment of Diagnostic Radiology, McGill University, Montreal, Quebec, Canada; and the kDepartment of Pathology, McGill University, Montreal, Quebec, Canada. Address correspondence and reprint requests to Bao Anh Do, 8607 Foucher, Montreal, Quebec, Canada H2P 2C3. E-mail: [email protected] Journal of Voice, Vol. 28, No. 2, pp. 258-261 0892-1997/$36.00 Ó 2014 The Voice Foundation http://dx.doi.org/10.1016/j.jvoice.2013.09.004
pharyngolaryngoscopy revealed a right vocal fold submucosal mass, with generalized thickening along the entire length of the fold (Figure 1). The fold did exhibit normal mobility. The mucosal wave was absent on the right fold and diminished anteriorly on the left fold due to the bulkiness of the lesion. Mild signs of laryngopharyngeal reflux were also present. Radiology. The magnetic resonance imaging (MRI) of the neck revealed a mildly spontaneously hyperintense right true vocal fold on fat saturated T1 gradient-echo (GRE) images and relative hyperintensity on fat-saturation T2-weighted images (Figures 2–5). It demonstrated strong enhancement following contrast infusion. The thickening of the right true vocal fold extended to the region of the anterior commissure but did not cross it. There was bulging of the fold into the subglottic space, but there was no true extension. The barium swallow and the modified barium swallow were unremarkable. Surgery. Suspension microlaryngoscopy and cold steel biopsy of the right-sided submucosal laryngeal mass was performed. A lateral microflap was performed and a submucosal plane was lifted. The mass was extremely rigid, most comparable with wood consistency. During the debridement, the surgeon took great care not to harm the mucosa overlying the lesion. Pathology Biopsies of the mass showed a low-grade myofibroblastic tumor without marked atypia, necrosis, or mitoses admixed with lymphocytes and plasma cells (Figure 6). There was no evidence of definite malignancy. The immunochemistry stains were positive for smooth muscle actin (SMA), desmin, and CD34. They were negative for CKAE1/AE3, myogenin, caldesmon, beta-catenin, S100, and anaplastic lymphoma kinase (ALK) protein. ALK protein fluorescence in situ hybridization was also negative. Moreover, the Ki67 proliferative index was low. Management Postoperatively, the patient was reviewed in our institutional tumor board conference. The team agreed for a conservative
Bao Anh Do, et al
Report on IMT of Larynx
FIGURE 1. Flexible transnasal pharyngolaryngoscopy revealing a right vocal fold submucosal mass with generalized thickening of the entire length of the fold. approach, which included laser debulking in the event of voice or airway compromise with close observation with serial MRI. There was a slight increase of the mass at a follow-up appointment clinically a few months postoperatively, without fear of airway obstruction. A trial of oral steroids for 4 weeks was initiated. Fifty milligrams of prednisone were given daily for 1 week, and the doses were tapered over the next 3 weeks. This resulted in a significant reduction in the tumor size. Currently, the patient is stable for 6 months, has a voice quality that is manageable, and a patent airway. DISCUSSION IMT is classified as a borderline neoplasm with uncertain behavior. Although, IMT of the head and neck is rare, the larynx is the most common site in the latter.2,3
FIGURE 2. MRI Coronal T1W postcontrast showing the thickening of the right true vocal fold.
259
FIGURE 3. MRI GRE precontrast of the true vocal folds. The etiology of IMT is still unclear. It was first thought to be of inflammatory origin; however, researchers refuted this hypothesis by finding clonal cytogenetic aberrations that would explain the behavior of this tumor.4 From the literature, common factors predisposing to IMT, such as trauma, smoking, and immune responses, have been proposed.5 The mean age of patients with IMT is around 43 years. They most often present to the clinic with hoarseness or dysphonia. Other symptoms that are occasionally present in this disease are dyspnea, stridor, globus, dysphagia, hemoptysis, cough, and otalgia.5 A small portion of patients with IMT can also have a syndrome of fever, weight loss, growth failure, malaise, anemia, thrombocytosis, polyclonal hyperglobulinemia, and elevated erythrocyte sedimentation rate, but these have not been documented in laryngeal IMT cases.4 IMT of the larynx is most often localized in the vocal folds, in the subglottis, or in the aryepiglottic folds.5 Our presentation of the IMT was particular on imaging. The use of MRI has not been reported in cases of laryngeal IMT. The
FIGURE 4. MRI GRE postcontrast of the true vocal folds.
260
Journal of Voice, Vol. 28, No. 2, 2014
FIGURE 6. Magnification (310) of hematoxylin- and eosin-stained IMT.
FIGURE 5. MRI fat saturation T2-weighted image of the true vocal folds.
thickening of the true vocal fold without extension is unique to our knowledge. Ni et al6 reported a case describing the findings on computed tomography imaging which showed uneven enhancement of the epiglottic-glossal surface. While Biron et al5 demonstrated a mass in the right subglottis that was not invading the laryngeal skeleton. These variations in radiological findings support the uncertain behavior of laryngeal IMT. Moreover, by looking into other locations of IMT, MRI findings that were reported also showed differences. In cases of paranasal sinuses IMT, one of the MRI revealed a nonhomogeneous and intermediate signal regardless of the sequence used.7 On another one, the mass was isointense on T1-weighted images and hypointense on T2-weighted images and was homogenously enhanced. In all these cases, MRI by itself is not diagnostic.8 IMT is a neoplasm composed of varying degrees of myofibroblastic spindle cells and inflammatory infiltrate of plasma cells, lymphocytes, and eosinophils.9,10 They are positive for SMA, desmin, and vimentin. In laryngeal IMT, ALK1 immunochemistry staining is usually positive although not universal.4,6,11 In our case, the lesion was diagnosed as an IMT because of its strong inflammatory component in addition to the tumor’s response to systemic steroids. A previous study looked at the outcomes in association with ALK1-reactivity and showed that ALK1-negativity seemed to be associated with metastasis, whereas ALK1-positivity was associated with recurrence.4 However, laryngeal IMT was not studied on those researches. Moreover, no cases of metastasis in laryngeal IMT have been reported up to now.6 The use of ALK FISH is not universal. In our case, the FISH was done in addition to the ALK immunochemistry for research purposes. None of the laryngeal IMT cases reported in the literature mentioned the FISH but only commented on ALK-1 immunochemistry staining. Coffin et al4 studied the ALK expression in IMT. They reported the correlation of ALK-1 reactivity on immunochemistry staining with the ALK FISH which supports our finding.
In the literature, the therapeutic approach varied from medical treatment with steroids, chemotherapy, or radiotherapy to surgical treatment with local excision with laser or cold dissection and even laryngectomy.5 Only a minority of reports observed local recurrence of disease and this was in association with surgically excised tumors. There was no reported recurrence in cases treated with systemic steroids. In this report, the size of the lesion was the limiting factor to an adequate excision. Although the tumor was sparing the cricoarytenoid joint, the tumor was surrounding it. The only way to adequately excise this lesion was to perform a hemilaryngectomy. Given the airway stability and quality of voice, this procedure was deemed to be too aggressive in presented clinical settings. Observation with serial laser debulking for airway or voice improvement much like in amyloidosis was agreed upon. CONCLUSION Briefly, there are many variants of IMT and its etiology is not fully understood. In general, IMT of the larynx has a benign clinical course with low rate of recurrence. There is no consensus on treatment with most proposing a conservative approach with local excision with possible adjuvant medical treatment such as steroids. Finally, it is imperative and necessary to have information in the literature about MRI findings in these cases and how do they compare with other cases of IMT in the head and neck region. This would help readers understand the disease further and keep such a relatively uncommon diagnosis in mind while managing challenging cases. REFERENCES 1. Coffin CM, Fletcher CDM. Inflammatory myofibroblastic tumour. In: Fletcher CDM, Unni KK, Mertens F, eds. WHO Classification of Tumors: Pathology and Genetics of Tumors of Soft Tissue and Bone. Lyon, France: IARC Press; 2002:91–94. 2. Wenig BM, Devaney K, Bisceglia M. Inflammatory myofibroblastic tumor of the larynx: a clinicopathologic study of eight cases simulating a malignant spindle cell neoplasm. Cancer. 1995;76:2217–2229. 3. Idrees MT, Huan Y, Woo P, et al. Inflammatory myofibroblastic tumor of larynx: a benign lesion with variable morphological spectrum. Ann Diagn Pathol. 2007;11:433–439.
Bao Anh Do, et al
Report on IMT of Larynx
4. Coffin CM, Hornick JL, Fletcher CD. Inflammatory myofibroblastic tumor: comparison of clinicopathologic, histologic, and immunohistochemical features including ALK expression in atypical and aggressive cases. Am J Surg Pathol. 2007;31:509–520. 5. Biron VL, Waghray R, Medlicott SA, Bosch JD. Inflammatorypseudotumours of the larynx: three cases and a review of the literature. J Otolaryngol Head Neck Surg. 2008;37:E32–E38. 6. Ni C, Xu YY, Zhou SH, Wang SQ. Differential diagnosis of inflammatory myofibroblastic tumour and low-grade myofibroblastic sarcoma: two case reports with a literature review. J Int Med Res. 2011;39:311–320. 7. Ushio M, Takeuchi N, Kikuchi S, Kaga K. Inflammatory pseudotumour of the paranasal sinuses—a case report. Auris Nasus Larynx. 2007;34: 533–536.
261 8. Inoue A, Egami N, Kitahara N, Yagi M. Differential diagnosis of proptosis: report of 2 cases. Auris Nasus Larynx. 2010;37:526–529. 9. Coffin CM, Watterson J, Priest JR, Dehner LP. Extrapulmonary inflammatory myofibroblastic tumor (inflammatory pseudotumor). A clinicopathologic and immunohistochemical study of 84 cases. Am J Surg Pathol. 1995;19:859–872. 10. Brcic I, Brcic L, Hutinec Z, Prgomet D, Seiwerth S. Laryngeal inflammatory myofibroblastic tumor in a man: a case report. Coll Antropol. 2010;34: 1127–1129. 11. V€olker HU, Scheich M, H€oller S, Str€obel P, Hagen R, M€ullerHermelink HK, Eck M. Differential diagnosis of laryngeal spindle cell carcinoma and inflammatory myofibroblastic tumor—report of two cases with similar morphology. Diagn Pathol. 2007;2:1.
