J Neurosurg 121:846–850, 2014 ©AANS, 2014
An isolated primary Rathke’s cleft cyst in the cerebellopontine angle Case report Jun Fan, M.D., Ph.D., Songtao Qi, M.D., Ph.D., Yuping Peng, M.D., Ph.D., Xi-an Zhang, M.D., Ph.D., Binghui Qiu, M.D., Ph.D., and Jun Pan, M.D., Ph.D. Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, People’s Republic of China Rathke’s cleft cysts (RCCs) are benign cysts typically located in the sellar or suprasellar region; ectopic isolated lesions are extremely rare. The authors describe the case of a 25-year-old man with a giant symptomatic RCC arising primarily at the cerebellopontine angle (CPA), only the second case reported thus far. The patient presented with a 2-year history of right hearing impairment and tinnitus accompanied by vertigo and headache and a 2-week history of right facial numbness. Subsequently, he underwent total cyst removal via retrosigmoid craniotomy with a good recovery. He experienced no recurrence during a 64-month follow-up period. The possible pathogenesis, differential diagnosis, and surgical treatment of such cysts are discussed in this article. Isolated ectopic RCCs can arise from the ectopic migration of Rathke’s pouch cells during the embryonic period. It is still difficult to distinguish ectopic RCCs from other cystic lesions of the CPA given the lack of specific imaging features. Aggressive resection of the cyst wall is not recommended, except when lesions do not closely adhere to adjacent structures. (http://thejns.org/doi/abs/10.3171/2014.3.JNS131837)
Key Words • cerebellopontine angle • Rathke’s cleft cyst • Rathke’s pouch • suboccipital retrosigmoid craniotomy • oncology
R
athke’s
cleft cysts (RCCs) are believed to develop in the infundibulohypophyseal axis and account for 13%–33% of incidentally encountered pituitary lesions.8,14,25 These cysts frequently occupy the sella or suprasellar space; occasionally they extend to the sphenoid sinus, planum sphenoidale, or clival region.4,6,10,17,19,21 However, isolated ectopic RCCs are extremely rare, and only one case at the cerebellopontine angle (CPA) has been reported in the literature.26 Herein, we present another case of RCC arising primarily from the CPA and discuss its pathogenesis, clinical features, and surgical treatment.
Case Report Clinical Presentation. A 25-year-old man was referred to our institution with a 2-year history of progressive hearing impairment and tinnitus on his right side, accompanied by intermittent vertigo and headache. These symptoms worsened over 6 months, and the patient had Abbreviations used in this paper: CN = cranial nerve; CPA = cerebellopontine angle; RCC = Rathke’s cleft cyst.
846
experienced right-sided facial numbness for 2 weeks. He did not demonstrate any other neurological deficits. Neurological examination revealed that he had hearing loss in the right ear (Gardner-Robertson Class IV), a decreased pinprick sensation in the V2 and V3 distributions of the right trigeminal nerve, and a positive Romberg sign. Radiological Aspects. Computed tomography scanning revealed a hypodense regular lesion at the right CPA. No enlargement or erosion of the internal auditory canal was detected (Fig. 1A). Magnetic resonance imaging revealed a 38 × 30 × 25–mm homogeneous sharpedged ovoid cyst without contrast enhancement at the right CPA, extending from the tentorium downward to the foramen magnum (Fig. 1D–F). The cyst had CSF-like signal intensity on both T1- and T2-weighted images (Fig. 1B and C). It exerted marked compression on the adjacent brainstem and cerebellum, but there was no sign of peritumoral edema or hydrocephalus. The differential diagnosis included cystic vestibular schwannoma, epidermoid cyst, and arachnoid cyst. This article contains some figures that are displayed in color online but in black-and-white in the print edition.
J Neurosurg / Volume 121 / October 2014
Rathke’s cleft cyst in the cerebellopontine angle
Fig. 1. Preoperative imaging of the ectopic RCC. A: Axial CT scan showing a hypodense mass in the right CPA without enlargement or erosion of the internal auditory canal. B and C: Homogeneous sharp-edged cystic mass with hypointense signal on axial T1-weighted MR image and hyperintensity on axial T2-weighted MR image. D–F: Axial, coronal, and sagittal Gd-enhanced MR images showing the lesion extending from the tentorium downward to the foramen magnum without contrast enhancement.
Operation and Pathological Findings. The patient underwent cyst resection via a right suboccipital retrosigmoid craniotomy. A huge translucent cystic lesion containing milky white fluid was observed during the operation. The cyst loosely adhered to cranial nerves (CNs) V, VIII, and IX as well as the brainstem and cerebellum (Fig. 2A and B). The cyst contents were completely evacuated, and total removal of the cyst wall was achieved after careful dissection (Fig. 2C and D). Pathological examination revealed that the cyst was lined partially by single-layer columnar epithelium and partially by stratified squamous epithelium without keratinization (Fig. 3). These findings confirmed the histological diagnosis of RCC. Postoperative Course. Postoperatively, the patient recovered well without any complication. The preoperative tinnitus, vertigo, headache, and facial numbness disappeared within 2 weeks. His hearing improved to GardnerRobertson Class II at 3 months after surgery. The most recent 64-month follow-up MRI study did not show any evidence of cyst recurrence (Fig. 4).
Discussion
Rathke’s cleft cysts are benign, epithelium-lined cysts filled with mucous or caseous material. These cysts are thought to arise from the remnants of Rathke’s pouch during the embryological migration. They are regarded as the most common incidentally found lesions in the sellar region, followed by pituitary adenomas. Sporadic RCCs loJ Neurosurg / Volume 121 / October 2014
cated in the nasopharynx, sphenoid sinus, or clivus have been described by other authors.4,6,10,17,19,21 However, it seems more appropriate to consider these lesions as an extension of intrasellar or suprasellar RCCs because of their close relationships with the originating site of Rathke’s pouch. Khalatbari et al.16 also suggested that most of the ectopic craniopharyngiomas described in past publications are essentially various extensions of large suprasellar lesions. In this regard, ectopic RCCs primarily developed beyond the craniopharyngeal canal are rather rarely reported in the literature. To our knowledge, only Zhou et al.26 have reported an isolated case in the CPA. The origin and pathogenesis of ectopic RCC remains unclear, but some authors have pointed out the possible continuum between RCCs and craniopharyngiomas.5,7,11,13 Multiple cases of the isolated CPA craniopharyngioma have been reported.3,16,20,24 Therefore, it is reasonable to assume that the formation mechanism of ectopic RCC is similar to that of craniopharyngioma. Rathke’s pouch arises as an invagination of the primitive oral cavity and fuses with the developing neural tube at the early embryological period. The migration path of Rathke’s pouch forms the craniopharyngeal duct; accordingly, the cells of Rathke’s pouch proliferate and rotate to form the anterior pituitary gland.9,15 Because of their different rates during the rotation, most Rathke’s pouch cells spread throughout the sellar region. However, a few cells may migrate outside the sellar region.2,10 Under such circumstances, the failure of these ectopic cells to regress during development may lead to the formation of an ectopic RCC. 847
J. Fan et al.
Fig. 2. Intraoperative photographs. A and B: A huge translucent cyst containing milky white fluid was observed in the right CPA. C and D: Both the cyst contents and cyst wall were totally removed, and surrounding structures remained intact after resection.
Our pathological examination showed that the cyst was lined partially by columnar epithelium and partially by stratified squamous epithelium, which overlapped histological features with the craniopharyngioma. Ikeda and Yoshimoto13 also reviewed 42 patients with RCCs and found that 3 cases had squamous epithelium in the cyst wall similar to that observed in craniopharyngiomas. These findings may support the hypothesis of a continuum between RCCs and craniopharyngiomas. Additionally, some authors have considered the squamous metaplasia as one of the factors affecting the recurrence of RCC.1,18,22 Aho et al.1 reported 118 surgical cases of RCC with a recurrence rate of 18%. They found that 32% of the patients with squamous metaplasia had a recurrence, whereas only 11% of those without metaplasia experi-
enced recurrent events. We did not find the association between the recurrence and squamous metaplasia in this case, but more case studies are needed to clarify this association. The variable clinical manifestations of RCCs mainly depend on the anatomical location of the cysts that may cause mass effect on adjacent structures. For lesions of the sellar region, specific symptoms typically present as visual dysfunctions, pituitary hormone deficits, or diabetes insipidus. Likewise, patients with ectopic lesions can present with other symptoms specific to cyst locations. For example, our patient had hearing impairment, tinnitus, and vertigo, symptoms consistent with those for other CPA lesions. The combination of CT and MRI studies may improve
Fig. 3. Histopathological examination with H & E staining revealed that the cyst was lined partially by single-layer columnar epithelium and partially by stratified squamous epithelium without keratinization. Original magnification ×100 (A) and ×200 (B).
848
J Neurosurg / Volume 121 / October 2014
Rathke’s cleft cyst in the cerebellopontine angle
Fig. 4. Follow-up MRI at 64 months after surgery showed no cyst recurrence. A: Axial T2-weighted MR image. B: Axial Gd-enhanced image. C: Coronal Gd-enhanced image.
the preoperative diagnosis of RCC. However, the differential diagnosis of RCC from other cystic lesions in the CPA remains difficult. Typically, the RCC has an oval or dumbbell shape, a variable intensity on MRI depending on the cystic content, and little or no cyst wall enhancement without any signs of invasion. The vestibular schwannoma is the most common tumor of the CPA and usually has a characteristic CT manifestation of enlargement or erosion of the internal auditory canal. In addition, enhanced tumor components are frequently found on MRI. Epidermoid cysts often present as a lobulated mass similar to CSF on CT or MRI, and calcification can sometimes be detected. They do not enhance but can exhibit restricted diffusion on diffusion-weighted imaging. The arachnoid cyst has a clearly outlined border, with signal intensity similar to that of CSF on MRI. No calcification and postcontrast enhancement can be observed in such cysts. Most authors recommend surgical removal for the treatment of symptomatic RCCs. However, the extent of resection of the cyst wall remains controversial.1,12,23 Although our earlier experience showed that radical removal would not necessarily reduce recurrence and in fact could increase the risk of postoperative complications, we still performed a total resection in the featured case. The reason is that the cyst wall in this case could be easily dissected without inflicting unnecessary damage to surrounding structures. In contrast, for cyst walls closely adhered to adjacent structures, a conservative surgical strategy is recommended for better functional outcomes.
Conclusions
We have described an isolated primary RCC at the CPA, the second such case in the literature. Lesions such as this can arise from ectopic migration of Rathke’s pouch cells during the embryonic period. Although the combination of CT and MRI is helpful, it is still difficult to distinguish between ectopic RCCs and other cystic lesions of the CPA. Aggressive resection of the cyst wall is not recommended except for lesions that are not closely adhered to adjacent structures. Acknowledgments We are grateful to Yiping Mo and Xiaoyu Qiu (medical secretary, Department of Neurosurgery, Nanfang Hospital, Southern
J Neurosurg / Volume 121 / October 2014
Medical University, Guangzhou, China) for their help with data collection. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. This study is financially supported by the Medical Scientific Research Foundation of Guangdong Province (No. B2012219), China. Author contributions to the study and manuscript preparation include the following. Conception and design: Fan. Acquisition of data: Zhang, Qiu, Pan. Analysis and interpretation of data: Fan. Drafting the article: Fan. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Qi. Administrative/technical/material support: Peng. Study supervision: Qi. References 1. Aho CJ, Liu C, Zelman V, Couldwell WT, Weiss MH: Surgical outcomes in 118 patients with Rathke cleft cysts. J Neurosurg 102:189–193, 2005 2. Barrow DL, Spector RH, Takei Y, Tindall GT: Symptomatic Rathke’s cleft cysts located entirely in the suprasellar region: review of diagnosis, management, and pathogenesis. Neurosurgery 16:766–772, 1985 3. Bashir EM, Lewis PD, Edwards MR: Posterior fast craniopharyngioma. Br J Neurosurg 10:613–615, 1996 4. Ben Hamouda K, Khaldi M, Jemel H, Ben Ismail M, Zemmel I: Rathke cleft cyst of the sphenoid bone and nasopharynx. Case illustration. J Neurosurg 103:1095, 2005 5. Chen CJ: Suprasellar and infrasellar craniopharyngioma with a persistent craniopharyngeal canal: case report and review of the literature. Neuroradiology 43:760–762, 2001 6. Chuang CC, Chen YL, Jung SM, Pai PC: A giant retroclival Rathke’s cleft cyst. J Clin Neurosci 17:1189–1191, 2010 7. Fager CA, Carter H: Intrasellar epithelial cysts. J Neurosurg 24:77–81, 1966 8. Famini P, Maya MM, Melmed S: Pituitary magnetic resonance imaging for sellar and parasellar masses: ten-year experience in 2598 patients. J Clin Endocrinol Metab 96:1633–1641, 2011 9. Garrè ML, Cama A: Craniopharyngioma: modern concepts in pathogenesis and treatment. Curr Opin Pediatr 19:471–479, 2007 10. Hanna E, Weissman J, Janecka IP: Sphenoclival Rathke’s cleft cysts: embryology, clinical appearance and management. Ear Nose Throat J 77:396–399, 403, 1998 11. Harrison MJ, Morgello S, Post KD: Epithelial cystic lesions of the sellar and parasellar region: a continuum of ectodermal derivatives? J Neurosurg 80:1018–1025, 1994
849
J. Fan et al. 12. Higgins DM, Van Gompel JJ, Nippoldt TB, Meyer FB: Symptomatic Rathke cleft cysts: extent of resection and surgical complications. Neurosurg Focus 31(1):E2, 2011 13. Ikeda H, Yoshimoto T: Clinicopathological study of Rathke’s cleft cysts. Clin Neuropathol 21:82–91, 2002 14. Jagannathan J, Kanter AS, Sheehan JP, Jane JA Jr, Laws ER Jr: Benign brain tumors: sellar/parasellar tumors. Neurol Clin 25:1231–1249, xi, 2007 15. Karavitaki N, Cudlip S, Adams CB, Wass JA: Craniopharyngiomas. Endocr Rev 27:371–397, 2006 16. Khalatbari MR, Borghei-Razavi H, Samadian M, Moharamzad Y, Schick U: Isolated primary craniopharyngioma in the cerebellopontine angle. J Clin Neurosci 19:1516–1519, 2012 17. Kim E: A case of ectopic Rathke’s cleft cyst in the prepontine cistern. J Korean Neurosurg Soc 52:152–155, 2012 18. Kim JE, Kim JH, Kim OL, Paek SH, Kim DG, Chi JG, et al: Surgical treatment of symptomatic Rathke cleft cysts: clinical features and results with special attention to recurrence. J Neurosurg 100:33–40, 2004 19. Kinoshita Y, Tominaga A, Usui S, Kurisu K: A Rathke’s cleft cyst located entirely in the anterior pituitary lobe. Acta Neurochir (Wien) 155:1085–1086, 2013 20. Link MJ, Driscoll CL, Giannini C: Isolated, giant cerebellopontine angle craniopharyngioma in a patient with Gardner syndrome: case report. Neurosurgery 51:221–226, 2002 21. Megdiche-Bazarbacha H, Ben Hammouda K, Aicha AB, Sebai R, Belghith L, Khaldi M, et al: Intrasphenoidal rathke cleft cyst. AJNR Am J Neuroradiol 27:1098–1100, 2006
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22. Mukherjee JJ, Islam N, Kaltsas G, Lowe DG, Charlesworth M, Afshar F, et al: Clinical, radiological and pathological features of patients with Rathke’s cleft cysts: tumors that may recur. J Clin Endocrinol Metab 82:2357–2362, 1997 23. Park JK, Lee EJ, Kim SH: Optimal surgical approaches for Rathke cleft cyst with consideration of endocrine function. Neurosurgery 70 (2 Suppl Operative):250–257, 2012 24. Shah GB, Bhaduri AS, Misra BK: Ectopic craniopharyngioma of the fourth ventricle: case report. Surg Neurol 68:96–98, 2007 25. Teramoto A, Hirakawa K, Sanno N, Osamura Y: Incidental pituitary lesions in 1,000 unselected autopsy specimens. Radiology 193:161–164, 1994 26. Zhou L, Luo L, Hui X, Chen H, Yu B, Guo G, et al: Primary Rathke’s cleft cyst in the cerebellopontine angle associated with apoplexy. Childs Nerv Syst 26:1813–1817, 2010
Manuscript submitted August 24, 2013. Accepted March 13, 2014. Please include this information when citing this paper: published online April 11, 2014; DOI: 10.3171/2014.3.JNS131837. Address correspondence to: Songtao Qi, M.D., Ph.D., Department of Neurosurgery, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Dadao Bei St., Guangzhou, 510515, People’s Republic of China. email: [email protected].
J Neurosurg / Volume 121 / October 2014
An isolated primary Rathke’s cleft cyst in the cerebellopontine angle Case report Jun Fan, M.D., Ph.D., Songtao Qi, M.D., Ph.D., Yuping Peng, M.D., Ph.D., Xi-an Zhang, M.D., Ph.D., Binghui Qiu, M.D., Ph.D., and Jun Pan, M.D., Ph.D. Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou, People’s Republic of China Rathke’s cleft cysts (RCCs) are benign cysts typically located in the sellar or suprasellar region; ectopic isolated lesions are extremely rare. The authors describe the case of a 25-year-old man with a giant symptomatic RCC arising primarily at the cerebellopontine angle (CPA), only the second case reported thus far. The patient presented with a 2-year history of right hearing impairment and tinnitus accompanied by vertigo and headache and a 2-week history of right facial numbness. Subsequently, he underwent total cyst removal via retrosigmoid craniotomy with a good recovery. He experienced no recurrence during a 64-month follow-up period. The possible pathogenesis, differential diagnosis, and surgical treatment of such cysts are discussed in this article. Isolated ectopic RCCs can arise from the ectopic migration of Rathke’s pouch cells during the embryonic period. It is still difficult to distinguish ectopic RCCs from other cystic lesions of the CPA given the lack of specific imaging features. Aggressive resection of the cyst wall is not recommended, except when lesions do not closely adhere to adjacent structures. (http://thejns.org/doi/abs/10.3171/2014.3.JNS131837)
Key Words • cerebellopontine angle • Rathke’s cleft cyst • Rathke’s pouch • suboccipital retrosigmoid craniotomy • oncology
R
athke’s
cleft cysts (RCCs) are believed to develop in the infundibulohypophyseal axis and account for 13%–33% of incidentally encountered pituitary lesions.8,14,25 These cysts frequently occupy the sella or suprasellar space; occasionally they extend to the sphenoid sinus, planum sphenoidale, or clival region.4,6,10,17,19,21 However, isolated ectopic RCCs are extremely rare, and only one case at the cerebellopontine angle (CPA) has been reported in the literature.26 Herein, we present another case of RCC arising primarily from the CPA and discuss its pathogenesis, clinical features, and surgical treatment.
Case Report Clinical Presentation. A 25-year-old man was referred to our institution with a 2-year history of progressive hearing impairment and tinnitus on his right side, accompanied by intermittent vertigo and headache. These symptoms worsened over 6 months, and the patient had Abbreviations used in this paper: CN = cranial nerve; CPA = cerebellopontine angle; RCC = Rathke’s cleft cyst.
846
experienced right-sided facial numbness for 2 weeks. He did not demonstrate any other neurological deficits. Neurological examination revealed that he had hearing loss in the right ear (Gardner-Robertson Class IV), a decreased pinprick sensation in the V2 and V3 distributions of the right trigeminal nerve, and a positive Romberg sign. Radiological Aspects. Computed tomography scanning revealed a hypodense regular lesion at the right CPA. No enlargement or erosion of the internal auditory canal was detected (Fig. 1A). Magnetic resonance imaging revealed a 38 × 30 × 25–mm homogeneous sharpedged ovoid cyst without contrast enhancement at the right CPA, extending from the tentorium downward to the foramen magnum (Fig. 1D–F). The cyst had CSF-like signal intensity on both T1- and T2-weighted images (Fig. 1B and C). It exerted marked compression on the adjacent brainstem and cerebellum, but there was no sign of peritumoral edema or hydrocephalus. The differential diagnosis included cystic vestibular schwannoma, epidermoid cyst, and arachnoid cyst. This article contains some figures that are displayed in color online but in black-and-white in the print edition.
J Neurosurg / Volume 121 / October 2014
Rathke’s cleft cyst in the cerebellopontine angle
Fig. 1. Preoperative imaging of the ectopic RCC. A: Axial CT scan showing a hypodense mass in the right CPA without enlargement or erosion of the internal auditory canal. B and C: Homogeneous sharp-edged cystic mass with hypointense signal on axial T1-weighted MR image and hyperintensity on axial T2-weighted MR image. D–F: Axial, coronal, and sagittal Gd-enhanced MR images showing the lesion extending from the tentorium downward to the foramen magnum without contrast enhancement.
Operation and Pathological Findings. The patient underwent cyst resection via a right suboccipital retrosigmoid craniotomy. A huge translucent cystic lesion containing milky white fluid was observed during the operation. The cyst loosely adhered to cranial nerves (CNs) V, VIII, and IX as well as the brainstem and cerebellum (Fig. 2A and B). The cyst contents were completely evacuated, and total removal of the cyst wall was achieved after careful dissection (Fig. 2C and D). Pathological examination revealed that the cyst was lined partially by single-layer columnar epithelium and partially by stratified squamous epithelium without keratinization (Fig. 3). These findings confirmed the histological diagnosis of RCC. Postoperative Course. Postoperatively, the patient recovered well without any complication. The preoperative tinnitus, vertigo, headache, and facial numbness disappeared within 2 weeks. His hearing improved to GardnerRobertson Class II at 3 months after surgery. The most recent 64-month follow-up MRI study did not show any evidence of cyst recurrence (Fig. 4).
Discussion
Rathke’s cleft cysts are benign, epithelium-lined cysts filled with mucous or caseous material. These cysts are thought to arise from the remnants of Rathke’s pouch during the embryological migration. They are regarded as the most common incidentally found lesions in the sellar region, followed by pituitary adenomas. Sporadic RCCs loJ Neurosurg / Volume 121 / October 2014
cated in the nasopharynx, sphenoid sinus, or clivus have been described by other authors.4,6,10,17,19,21 However, it seems more appropriate to consider these lesions as an extension of intrasellar or suprasellar RCCs because of their close relationships with the originating site of Rathke’s pouch. Khalatbari et al.16 also suggested that most of the ectopic craniopharyngiomas described in past publications are essentially various extensions of large suprasellar lesions. In this regard, ectopic RCCs primarily developed beyond the craniopharyngeal canal are rather rarely reported in the literature. To our knowledge, only Zhou et al.26 have reported an isolated case in the CPA. The origin and pathogenesis of ectopic RCC remains unclear, but some authors have pointed out the possible continuum between RCCs and craniopharyngiomas.5,7,11,13 Multiple cases of the isolated CPA craniopharyngioma have been reported.3,16,20,24 Therefore, it is reasonable to assume that the formation mechanism of ectopic RCC is similar to that of craniopharyngioma. Rathke’s pouch arises as an invagination of the primitive oral cavity and fuses with the developing neural tube at the early embryological period. The migration path of Rathke’s pouch forms the craniopharyngeal duct; accordingly, the cells of Rathke’s pouch proliferate and rotate to form the anterior pituitary gland.9,15 Because of their different rates during the rotation, most Rathke’s pouch cells spread throughout the sellar region. However, a few cells may migrate outside the sellar region.2,10 Under such circumstances, the failure of these ectopic cells to regress during development may lead to the formation of an ectopic RCC. 847
J. Fan et al.
Fig. 2. Intraoperative photographs. A and B: A huge translucent cyst containing milky white fluid was observed in the right CPA. C and D: Both the cyst contents and cyst wall were totally removed, and surrounding structures remained intact after resection.
Our pathological examination showed that the cyst was lined partially by columnar epithelium and partially by stratified squamous epithelium, which overlapped histological features with the craniopharyngioma. Ikeda and Yoshimoto13 also reviewed 42 patients with RCCs and found that 3 cases had squamous epithelium in the cyst wall similar to that observed in craniopharyngiomas. These findings may support the hypothesis of a continuum between RCCs and craniopharyngiomas. Additionally, some authors have considered the squamous metaplasia as one of the factors affecting the recurrence of RCC.1,18,22 Aho et al.1 reported 118 surgical cases of RCC with a recurrence rate of 18%. They found that 32% of the patients with squamous metaplasia had a recurrence, whereas only 11% of those without metaplasia experi-
enced recurrent events. We did not find the association between the recurrence and squamous metaplasia in this case, but more case studies are needed to clarify this association. The variable clinical manifestations of RCCs mainly depend on the anatomical location of the cysts that may cause mass effect on adjacent structures. For lesions of the sellar region, specific symptoms typically present as visual dysfunctions, pituitary hormone deficits, or diabetes insipidus. Likewise, patients with ectopic lesions can present with other symptoms specific to cyst locations. For example, our patient had hearing impairment, tinnitus, and vertigo, symptoms consistent with those for other CPA lesions. The combination of CT and MRI studies may improve
Fig. 3. Histopathological examination with H & E staining revealed that the cyst was lined partially by single-layer columnar epithelium and partially by stratified squamous epithelium without keratinization. Original magnification ×100 (A) and ×200 (B).
848
J Neurosurg / Volume 121 / October 2014
Rathke’s cleft cyst in the cerebellopontine angle
Fig. 4. Follow-up MRI at 64 months after surgery showed no cyst recurrence. A: Axial T2-weighted MR image. B: Axial Gd-enhanced image. C: Coronal Gd-enhanced image.
the preoperative diagnosis of RCC. However, the differential diagnosis of RCC from other cystic lesions in the CPA remains difficult. Typically, the RCC has an oval or dumbbell shape, a variable intensity on MRI depending on the cystic content, and little or no cyst wall enhancement without any signs of invasion. The vestibular schwannoma is the most common tumor of the CPA and usually has a characteristic CT manifestation of enlargement or erosion of the internal auditory canal. In addition, enhanced tumor components are frequently found on MRI. Epidermoid cysts often present as a lobulated mass similar to CSF on CT or MRI, and calcification can sometimes be detected. They do not enhance but can exhibit restricted diffusion on diffusion-weighted imaging. The arachnoid cyst has a clearly outlined border, with signal intensity similar to that of CSF on MRI. No calcification and postcontrast enhancement can be observed in such cysts. Most authors recommend surgical removal for the treatment of symptomatic RCCs. However, the extent of resection of the cyst wall remains controversial.1,12,23 Although our earlier experience showed that radical removal would not necessarily reduce recurrence and in fact could increase the risk of postoperative complications, we still performed a total resection in the featured case. The reason is that the cyst wall in this case could be easily dissected without inflicting unnecessary damage to surrounding structures. In contrast, for cyst walls closely adhered to adjacent structures, a conservative surgical strategy is recommended for better functional outcomes.
Conclusions
We have described an isolated primary RCC at the CPA, the second such case in the literature. Lesions such as this can arise from ectopic migration of Rathke’s pouch cells during the embryonic period. Although the combination of CT and MRI is helpful, it is still difficult to distinguish between ectopic RCCs and other cystic lesions of the CPA. Aggressive resection of the cyst wall is not recommended except for lesions that are not closely adhered to adjacent structures. Acknowledgments We are grateful to Yiping Mo and Xiaoyu Qiu (medical secretary, Department of Neurosurgery, Nanfang Hospital, Southern
J Neurosurg / Volume 121 / October 2014
Medical University, Guangzhou, China) for their help with data collection. Disclosure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. This study is financially supported by the Medical Scientific Research Foundation of Guangdong Province (No. B2012219), China. Author contributions to the study and manuscript preparation include the following. Conception and design: Fan. Acquisition of data: Zhang, Qiu, Pan. Analysis and interpretation of data: Fan. Drafting the article: Fan. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Qi. Administrative/technical/material support: Peng. Study supervision: Qi. References 1. Aho CJ, Liu C, Zelman V, Couldwell WT, Weiss MH: Surgical outcomes in 118 patients with Rathke cleft cysts. J Neurosurg 102:189–193, 2005 2. Barrow DL, Spector RH, Takei Y, Tindall GT: Symptomatic Rathke’s cleft cysts located entirely in the suprasellar region: review of diagnosis, management, and pathogenesis. Neurosurgery 16:766–772, 1985 3. Bashir EM, Lewis PD, Edwards MR: Posterior fast craniopharyngioma. Br J Neurosurg 10:613–615, 1996 4. Ben Hamouda K, Khaldi M, Jemel H, Ben Ismail M, Zemmel I: Rathke cleft cyst of the sphenoid bone and nasopharynx. Case illustration. J Neurosurg 103:1095, 2005 5. Chen CJ: Suprasellar and infrasellar craniopharyngioma with a persistent craniopharyngeal canal: case report and review of the literature. Neuroradiology 43:760–762, 2001 6. Chuang CC, Chen YL, Jung SM, Pai PC: A giant retroclival Rathke’s cleft cyst. J Clin Neurosci 17:1189–1191, 2010 7. Fager CA, Carter H: Intrasellar epithelial cysts. J Neurosurg 24:77–81, 1966 8. Famini P, Maya MM, Melmed S: Pituitary magnetic resonance imaging for sellar and parasellar masses: ten-year experience in 2598 patients. J Clin Endocrinol Metab 96:1633–1641, 2011 9. Garrè ML, Cama A: Craniopharyngioma: modern concepts in pathogenesis and treatment. Curr Opin Pediatr 19:471–479, 2007 10. Hanna E, Weissman J, Janecka IP: Sphenoclival Rathke’s cleft cysts: embryology, clinical appearance and management. Ear Nose Throat J 77:396–399, 403, 1998 11. Harrison MJ, Morgello S, Post KD: Epithelial cystic lesions of the sellar and parasellar region: a continuum of ectodermal derivatives? J Neurosurg 80:1018–1025, 1994
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Manuscript submitted August 24, 2013. Accepted March 13, 2014. Please include this information when citing this paper: published online April 11, 2014; DOI: 10.3171/2014.3.JNS131837. Address correspondence to: Songtao Qi, M.D., Ph.D., Department of Neurosurgery, Nanfang Hospital, Southern Medical University, 1838 Guangzhou Dadao Bei St., Guangzhou, 510515, People’s Republic of China. email: [email protected].
J Neurosurg / Volume 121 / October 2014
