Otology & Neurotology 37:e167–e168 ß 2014, Otology & Neurotology, Inc.
Imaging Case of the Month
Minimal Growth of Intracochlear Schwannoma Over 7 Years Stephen Schoeff, Bradley W. Kesser, and ySugoto Mukherjee From the Departments of Otolaryngology–Head and Neck Surgery; and yRadiology and Medical Imaging, University of Virginia Health System, Charlottesville, Virginia
Approximately 21/2 years after initial presentation, she had 3 episodes of debilitating Me´nie`re’s disease–like vertiginous episodes lasting 3 to 4 days. The vertigo episodes ultimately resolved without treatment. Because her vertiginous episodes completely abated after the third episode, she did not seek surgery or stereotactic treatment and, instead, was followed with serial MRIs. Now, more than 7 years after presentation, the lesion demonstrates progression into the basal, middle, and apical turns (Fig. 2), along with slight transmodiolar extension into the distal internal auditory canal (IAC). Extension into the IAC may be an indication for intervention, given the comorbidity of the facial nerve, but continued observation remains a viable alternative, given the slow growth of this neoplasm. Here, we present a patient followed with serial imaging over 7 years, and although MRI follow-up has been performed occasionally up to 15 years, most reports in the literature follow patients for 5 years or fewer (2,3). The opportunity to present several serial images from a single patient is a unique perspective of the growth and development of the lesion in this 1 patient. Optimal evaluation of intralabyrinthine lesions includes a combination of thin section, heavily T2-weighted sequences along with thin section precontrast and postcontrast axial and coronal T1-weighted MRI. ILS characteristically appear as filling defects within the normally high signal region of the cochlea on T2-weighted sequences and as a focal, intense enhancement on the postcontrast thin section T1 sequences. The differential diagnosis of a bright or enhancing lesion within the bony labyrinth includes schwannoma, neurofibroma, lipoma (bright on precontrast and postcontrast T1 sequences), metastasis, xanthoma, hemorrhage, and inflammation (5). The properties of this patient’s lesion leading to the diagnosis of ILS include its imaging characteristics, clinical behavior, and slow growth pattern. Inflammatory and other nonneoplastic lesions usually demonstrate a hazier and diffuse pattern of enhancement, which improves on followup imaging. Precontrast T1-weighted imaging is also important to rule out T1 hyperintense lesions such as a lipoma or intralabyrinthine hemorrhage.
Intralabyrinthine schwannomas (ILS) constitute approximately 10% of acoustic and vestibular schwannomas1 and have been increasingly diagnosed since the advent of gadolinium-enhanced high-resolution magnetic resonance imaging (MRI). These slow-growing, benign tumors often evade diagnosis because of a varied clinical and radiologic picture. Salzman et al. suggested a system for diagnosis and classification of ILS by location, the most common of which is intracochlear, followed by transmodiolar, vestibulocochlear, transmacular, and transotic.2 Intracochlear schwannomas are most frequently located in the basal turn and modiolus (1–4). The natural history of these tumors is unclear, although several studies report very slow or minimal growth over years, slower than their counterparts arising from the vestibular nerve in the internal auditory canal and/or cerebellopontine angle (1,4). Nearly every patient presents with hearing loss and experiences a profound hearing loss in the affected ear regardless of tumor location (1–4). A 46-year-old woman presented with a 1 month history of right-sided hearing loss; audiometry showed moderate-severe asymmetric right-sided low-frequency sensorineural hearing loss (SNHL). She first noticed the hearing loss shortly after resolution of an upper respiratory infection, and ipsilateral tinnitus was her only other symptom. Contrast-enhanced MRI at the time revealed a small area of enhancement at the basal turn of the right cochlea considered to be nonspecific inflammation (Fig. 1A). She was treated for sudden sensorineural hearing loss (SSNHL) with oral followed by intratympanic steroids, which provided interval hearing improvement. For the next 18 months, she progressively lost all hearing in her right ear. Follow up MRI’s at 2 and 4 years showed minimally progressive focal enhancement in the basal turn of the cochlea (Fig. 1, B and C). Address correspondence and reprint requests to Bradley W. Kesser, M.D., Department of Otolaryngology–Head and Neck Surgery, University of Virginia Health System, Box 800713, Charlottesville, VA 22908–0713; E-mail: [email protected] The authors disclose no conflicts of interest.
e167
Copyright © 2016 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
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S. SCHOEFF ET AL.
FIG. 1. Axial postcontrast T1-weighted fat-saturated images (A, B, and C ) demonstrate minimal progression of the intracochlear schwannoma (white arrow ) from 2006 through 2010. Note the change in the focal enhancement, which appears more solid as compared with the baseline magnetic resonance, along with increasing size involving the entire basal turn of the cochlea by 2010.
FIG. 2. Sequential axial T1 postcontrast, fat-saturated images from 2013 show further progression of the intracochlear schwannoma now involving the basal (arrow in A), middle (arrow in B), and apical turns (arrow in C) of the cochlea with slight extension into the IAC.
Intralabyrinthine schwannomas are rare lesions characterized by early hearing loss and very slow growth. Diagnosis is made based on MRI characteristics. Given the early loss of hearing in the clinical course of this slowgrowing lesion, observation (even out to 7 yr) with serial MRI is a reasonable management option.
2. 3. 4.
REFERENCES 5. 1. Tieleman A, Casselman JW, Somers T, et al. Imaging of intralabyrinthine schwannomas: a retrospective study of 52 cases with
emphasis on lesion growth. AJNR Am J Neuroradiol 2008;29: 898–905. Salzman KL, Childs AM, Davidson HC, Kennedy RJ, Shelton C, Harnsberger HR. Intralabyrinthine schwannomas: imaging diagnosis and classification. AJNR Am J Neuroradiol 2012;33:104–9. Neff BA, Willcox TO Jr, Sataloff RT. Intralabyrinthine schwannomas. Otol Neurotol 2003;24:299–307. Deux JF, Marsot-Dupuch K, Ouayoun M, et al. Slow-growing labyrinthine masses: contribution of MRI to diagnosis, follow-up and treatment. Neuroradiology 1998;40:684–9. Harnsberger R, Glastonbury CM, Michel MA, et al. Diagnostic Imaging: Head and Neck, 2nd ed. Baltimore: Lippincott, Williams, & Wilkins; 2010.
Otology & Neurotology, Vol. 37, No. 3, 2016
Copyright © 2016 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
Imaging Case of the Month
Minimal Growth of Intracochlear Schwannoma Over 7 Years Stephen Schoeff, Bradley W. Kesser, and ySugoto Mukherjee From the Departments of Otolaryngology–Head and Neck Surgery; and yRadiology and Medical Imaging, University of Virginia Health System, Charlottesville, Virginia
Approximately 21/2 years after initial presentation, she had 3 episodes of debilitating Me´nie`re’s disease–like vertiginous episodes lasting 3 to 4 days. The vertigo episodes ultimately resolved without treatment. Because her vertiginous episodes completely abated after the third episode, she did not seek surgery or stereotactic treatment and, instead, was followed with serial MRIs. Now, more than 7 years after presentation, the lesion demonstrates progression into the basal, middle, and apical turns (Fig. 2), along with slight transmodiolar extension into the distal internal auditory canal (IAC). Extension into the IAC may be an indication for intervention, given the comorbidity of the facial nerve, but continued observation remains a viable alternative, given the slow growth of this neoplasm. Here, we present a patient followed with serial imaging over 7 years, and although MRI follow-up has been performed occasionally up to 15 years, most reports in the literature follow patients for 5 years or fewer (2,3). The opportunity to present several serial images from a single patient is a unique perspective of the growth and development of the lesion in this 1 patient. Optimal evaluation of intralabyrinthine lesions includes a combination of thin section, heavily T2-weighted sequences along with thin section precontrast and postcontrast axial and coronal T1-weighted MRI. ILS characteristically appear as filling defects within the normally high signal region of the cochlea on T2-weighted sequences and as a focal, intense enhancement on the postcontrast thin section T1 sequences. The differential diagnosis of a bright or enhancing lesion within the bony labyrinth includes schwannoma, neurofibroma, lipoma (bright on precontrast and postcontrast T1 sequences), metastasis, xanthoma, hemorrhage, and inflammation (5). The properties of this patient’s lesion leading to the diagnosis of ILS include its imaging characteristics, clinical behavior, and slow growth pattern. Inflammatory and other nonneoplastic lesions usually demonstrate a hazier and diffuse pattern of enhancement, which improves on followup imaging. Precontrast T1-weighted imaging is also important to rule out T1 hyperintense lesions such as a lipoma or intralabyrinthine hemorrhage.
Intralabyrinthine schwannomas (ILS) constitute approximately 10% of acoustic and vestibular schwannomas1 and have been increasingly diagnosed since the advent of gadolinium-enhanced high-resolution magnetic resonance imaging (MRI). These slow-growing, benign tumors often evade diagnosis because of a varied clinical and radiologic picture. Salzman et al. suggested a system for diagnosis and classification of ILS by location, the most common of which is intracochlear, followed by transmodiolar, vestibulocochlear, transmacular, and transotic.2 Intracochlear schwannomas are most frequently located in the basal turn and modiolus (1–4). The natural history of these tumors is unclear, although several studies report very slow or minimal growth over years, slower than their counterparts arising from the vestibular nerve in the internal auditory canal and/or cerebellopontine angle (1,4). Nearly every patient presents with hearing loss and experiences a profound hearing loss in the affected ear regardless of tumor location (1–4). A 46-year-old woman presented with a 1 month history of right-sided hearing loss; audiometry showed moderate-severe asymmetric right-sided low-frequency sensorineural hearing loss (SNHL). She first noticed the hearing loss shortly after resolution of an upper respiratory infection, and ipsilateral tinnitus was her only other symptom. Contrast-enhanced MRI at the time revealed a small area of enhancement at the basal turn of the right cochlea considered to be nonspecific inflammation (Fig. 1A). She was treated for sudden sensorineural hearing loss (SSNHL) with oral followed by intratympanic steroids, which provided interval hearing improvement. For the next 18 months, she progressively lost all hearing in her right ear. Follow up MRI’s at 2 and 4 years showed minimally progressive focal enhancement in the basal turn of the cochlea (Fig. 1, B and C). Address correspondence and reprint requests to Bradley W. Kesser, M.D., Department of Otolaryngology–Head and Neck Surgery, University of Virginia Health System, Box 800713, Charlottesville, VA 22908–0713; E-mail: [email protected] The authors disclose no conflicts of interest.
e167
Copyright © 2016 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
e168
S. SCHOEFF ET AL.
FIG. 1. Axial postcontrast T1-weighted fat-saturated images (A, B, and C ) demonstrate minimal progression of the intracochlear schwannoma (white arrow ) from 2006 through 2010. Note the change in the focal enhancement, which appears more solid as compared with the baseline magnetic resonance, along with increasing size involving the entire basal turn of the cochlea by 2010.
FIG. 2. Sequential axial T1 postcontrast, fat-saturated images from 2013 show further progression of the intracochlear schwannoma now involving the basal (arrow in A), middle (arrow in B), and apical turns (arrow in C) of the cochlea with slight extension into the IAC.
Intralabyrinthine schwannomas are rare lesions characterized by early hearing loss and very slow growth. Diagnosis is made based on MRI characteristics. Given the early loss of hearing in the clinical course of this slowgrowing lesion, observation (even out to 7 yr) with serial MRI is a reasonable management option.
2. 3. 4.
REFERENCES 5. 1. Tieleman A, Casselman JW, Somers T, et al. Imaging of intralabyrinthine schwannomas: a retrospective study of 52 cases with
emphasis on lesion growth. AJNR Am J Neuroradiol 2008;29: 898–905. Salzman KL, Childs AM, Davidson HC, Kennedy RJ, Shelton C, Harnsberger HR. Intralabyrinthine schwannomas: imaging diagnosis and classification. AJNR Am J Neuroradiol 2012;33:104–9. Neff BA, Willcox TO Jr, Sataloff RT. Intralabyrinthine schwannomas. Otol Neurotol 2003;24:299–307. Deux JF, Marsot-Dupuch K, Ouayoun M, et al. Slow-growing labyrinthine masses: contribution of MRI to diagnosis, follow-up and treatment. Neuroradiology 1998;40:684–9. Harnsberger R, Glastonbury CM, Michel MA, et al. Diagnostic Imaging: Head and Neck, 2nd ed. Baltimore: Lippincott, Williams, & Wilkins; 2010.
Otology & Neurotology, Vol. 37, No. 3, 2016
Copyright © 2016 Otology & Neurotology, Inc. Unauthorized reproduction of this article is prohibited.
