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Symptomatic Rathke's cleft cysts
42
Surg Neurol 1983;19:42-5
Symptomatic Rathke's Cleft Cysts D. Rout, L. Das, V.R.K. Rao, and V.V. Radhakrishnan Departments of Neurosurgery, Neuroradiology, and Neuropathology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
Rout D, Das L, Rao VRK, Radhakrishnan VV. Symptomatic Rathke's cleft cysts. Surg Neurol 1983;19:42-5. T w o unusual cases of symptomatic Rathke's cleft cysts are reported. In one, the cyst was entirely supraseUar with a normal sella turcica. The gross visual failure, hypothalamic disturbances, and hypopituitarism of the patient resolved after a transfrontal aspiration and partial excision of the wall of the cyst. The second patient was a pituitary dwarf with hypothalamic dysfunction, but with normal vision. The patient had a large intrasellar cyst that exhibited marked suprasellar extension with calcification of the capsular rim. After transsphenoidal aspiration and partial excision of the wall of the cyst, the patient achieved a satisfactory recovery. The differential features between Rathke's cleft cyst and craniopharyngioma are highlighted. KEYWORDS: Rathke's cleft cyst; Suprasellar cyst; Ciliated epithelium; Craniopharyngioma
Rathke's cleft cysts are assumed to develop from remnants o f Rathke's pouch, an invagination of the stom o d e u m [3,22,23,30]. These cysts are characteristically lined by columnar or cuboidal epithelium, often with cilia and goblet cells [3,11,20,30]. Although asymptomatic Rathke's cleft cysts are relatively c o m m o n (they are found in 1 3 % - 2 2 % of all cases at autopsy [2,14,22,23]), only 61 cases of symptom-producing cysts have been reported in the literature [1,9-11,13,15, 21,26,27,29,30]. Most o f the reported symptomatic Rathke's cleft cysts are intrasellar and have caused hypopituitarism and headache in the patient. One-third of Rathke's cleft cysts, however, do have a c o m p o n e n t o f significant suprasellar extension, which produces chiasmal compression, hypothalamic dysfunction, a n d - - r a r e l y - - o b s t r u c t i v e hydrocephalus. Occasionally they may present with features of aseptic meningitis [26,27]. Chronic inflammation with abscess formation in a Rathke's cleft cyst is docu-
Address reprint requests to." Dr. D. Rout, Department of Neurosurgery, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum-695011, Kerala, India.
© 1983 by ElsevierSciencePublishingCo., Inc.
mented in one case [ 17]. H o w e v e r , entirely suprasellar symptomatic Rathke's cleft cyst with normal sella turcica is extremely uncommon. Yoshida et al [30], in a review of 35 cases o f symptomatic Rathke's cleft cyst reported through 1977, recorded a suprasellar location in five cases, although none of them had a normal sella turcica. Calcification in a Rathke's cleft cyst with a single epithelial lining, to our knowledge, is not reported in the literature, although mixed forms of Rathke's cleft cyst and craniopharyngioma are described on histologic grounds [11,27]. This paper describes two rare cases of symptomatic Rathke's cleft cyst. In one, the cyst was entirely suprasellar with a normal sella turcica causing marked chiasmal compression in addition to hypopituitarism and hypothalamic disturbances; and in the other, it was a large intrasellar cyst with marked suprasellar extension with calcification o f the capsular rim presenting with headache, panhypopituitarism, and hypothalamic dysfunction but no visual symptoms. Both cases were treated surgically with good results.
Case R e p o r t s Case I
A 19-year-old girl was referred to us in August 1981 with a history of headache and vomiting for 1.5 years, hypothalamic disturbances in the form of lethargy, hyperhydrosis, polyuria, and polydypsia for 1 year, amenorrhea for 6 months, and progressive visual failure for 4 months. She had bilateral primary optic atrophy with no vision in the left eye and a temporal field cut in the right eye; her visual acuity was 3/60. A clinical diagnosis of a suprasellar mass, probably a craniopharyngioma, was made. X-ray examination of the skull showed a normal sella turcica (Figure 1), and an angiogram of the left carotid artery with cross compression revealed a suprasellar mass (Figure 2). A craniotomy of the right frontotemporal lobe revealed a greyish-white suprasellar cyst with a moderately thick capsule over which the optic nerves and chiasm were markedly stretched. N e e d l e aspiration obtained 8 10 cm 3 of yellowish, pultaceous material; the cyst wall collapsed after the aspiration and could be freed from 0090-3019/83/010042-04503.00
Rathke's Cleft Cysts
Surg Neurol 1983;19:42-5
4
cleft cyst was made. The bacterial culture of the cystic contents did not grow any organism. The period after surgery was uneventful. Her vision improved rapidly and she was discharged with 1/60 vision in the left eye and 6/60 in the right, with an improvement in her visual fields. On examination after 6 months, her vision had improved remarkably, and she was able to perform her household duties normally. However, the amenorrhea had persisted. Case 2
the optic apparatus. A subtotal excision of cyst wall was achieved, leaving a small portion adherent to the hypothalamic region and to the planum sphenoidale anteriorly. Histologically, the cyst wall was composed of a single layer of ciliated columnar epithelium supported on a collagenous connective tissue stroma (Figure 3). The luminal surface of the cyst was heavily infiltrated with chronic inflammatory cells. Cyst fluid on smear examination revealed amorphous periodic acid-Schiffpositive material. No cholesterol crystals, keratin, or calcific changes were identified. A histologic diagnosis of Rathke's
A 20-year-old girl presented in March 1980 with a history of retarded physical development for 10 years, occasional headaches, loss of appetite, and easy fatiguability for 4 years and repeated episodes of transient loss of consciousness for 1 year; there were no visual symptoms. She was a classical pituitary dwarf, and she had thin, shiny, hairless skin. She also had undeveloped breasts and other secondary sexual characters; she had not attained menarche. There were no other neurologic deficits. X-ray examination of the skull showed a markedly enlarged sella turcica with a rim of suprasellar calcification. An angiogram of the right carotid artery showed an opening of the carotid siphon. A pneumoencephalogram confirmed an intrasellar mass with suprasellar extension elevating the floor of the anterior third ventricle (Figure 4). An orbital venogram showed definite parasellar extension. Transsphenoidal aspiration produced 7 cm ~ of thick mucoid brownish fluid; after aspiration the suprasellar calcification was reduced by 1.5 cm. Her headache and vomiting lessened, and she was discharged with advice to attend the endocrinology clinic for study. She re-
Figure 2. Patient 1: Arteriogram of the left carotid artery with cross
Figure 3. Patient 1." Photomicrograph of the cyst wall showing single layer of ciliated columnar epithelium with attenuation (H & E; × 110L
~iii~i,i,,~i~i~¸
Figure 1. Patient 1: Lateral view of the skull showing normal sella turcica.
compression showing midline suprasellar mass.
44
Surg Neurol 1983;19:42-5
Figure 4. Patient 2: Pneumoencephalogram showing enlarged sella turcica and suprasellar extension of the cyst with capsular rim calcification.
turned 4 months later complaining of recurrent headaches and vomiting; a conray ventriculogram revealed a recurrence o f the cyst indenting the floor of the anterior third ventricle. Brownish cystic fluid was aspirated through a transsphenoidal approach and the shining cyst wall was partially excised. Histopathologic examination revealed a cyst lined by cuboidal or low columnar epithelium with goblet cells, supported on a thin basement membrane. There was no evidence of stratification or keratinization in the cyst wall. The histologic features were consistent with a Rathke's cleft cyst. H e r treatment after surgery was uneventful. She made a satisfactory symptomatic improvement and was discharged on a regimen of hormonal replacement. T h e r e has been no symptomatic recurrence since the last operation. Discussion More frequent reports in recent literature indicate that symptomatic Rathke's cleft cysts are more common than suspected [26]. Since 1913 when Goldzieher described the first case, 61 cases have been reported in the literature, of which at least 36 were diagnosed at operation [1,3,5,9-11,13,15,17,18,21,25-27,29,30]. Generally these cysts are intrasellar with or without suprasellar extension. Entirely suprasellar location of the cyst with a normal sella turcica, like that of our first patient, is extremely uncommon. In a review of 35 cases, Yoshida et al [30] recorded supraseUar cysts in five of them.
Rout et al
Although there is no mention about the sella turcica in two cases, it was abnormal in the other three. Interestingly, the cyst was intrasphenoidal in one. Intrasellar epithelial cysts derived from remnants of Rathke's pouch with a lining of columnar or cuboidal cells, often with cilia and goblet cells, are called Rathke's cleft cysts [2-4,7,8,19]. However, pituitary [16,18,25,28], colloid [9], and intrasellar epithelial [6,24] cysts have been used as synonyms. Some authors believe that these cysts may arise from neuroepithelium [4,24] or by reverse metaplasia from anterior pituitary cells [ 16]. Both Rathke's cleft cyst and craniopharyngioma have a common origin: the remnants of Rathke's pouch. But they have different histologic differentiations [30]. Craniopharyngiomas are derived from squamous cell rests of the craniopharyngeal duct [20,26]. These are primarily suprasellar neoplasms that exhibit frequent radiologic calcification and contrast-medium enhancement on computed tomography scans. They also often have a cystic component with thick brown or greenish fluid resembling machine oil and are lined by stratified squamous epithelium that shows frequent keratinization. Conversely, Rathke's cleft cysts are primarily intrasellar, nonneoplastic lesions that do not exhibit radiologic calcification (in contrast to our patient 2) or contrast-medium enhancement on computed tomography scans [3,6,11,13,15,20,26,30]. These cysts are characteristically lined by ciliated columnar or cuboidal epithelium and often have mucus-secreting cells without any evidence of keratinization [3,6,11,13,20,26,30]. Whereas radical excision or partial removal followed by radiation therapy has been widely recommended for craniopharyngiomas in order to avoid recurrence, simple aspiration or partial excision of the cyst wall has been advocated for symptomatic Rathke's cleft cysts [6,13,15,25,26,30]. Rathke's cleft cysts may, however, rarely have small foci of squamous epithelia even with keratinization [3,8,11,12,20,24,26,27,30]. Solid components that have been described as pituitary adenomas [9,24], transitional cell tumors o f the pituitary [ 11], or simple tumor nodules [30] have been described in five cases of symptomatic Rathke's cleft cyst, of which three with stratified squamous epithelial lining had symptomatic recurrence after partial removal [3,10,18,26,30]. These are considered as mixed forms of craniopharyngioma and Rathke's cleft cyst, and they are neoplastic in their behavior [30]. Existence o f mixed forms of Rathke's cleft cyst and of craniopharyngioma has also been demonstrated by others [11,27]. The fluid of the Rathke's cleft cyst--although often described as white m u c o i d - - m a y be clear, blue, green, yellow, thick mucopurulent (as in our patient 1), and even brown, like machine oil [13,30]. Although pituitary adenoma has been the commonest preoperative diagnosis in these cases [15,30], non-
Rathke's Cleft Cysts
enhancing cysts such as cystic craniopharyngioma, cystic pituitary adenoma, cysticercosis cysts, arachnoid cyst, and epidermoid cyst are presently considered in the differential diagnosis of Rathke's cleft cyst when computed tomography scanning demonstrates a homogenous, low-density lesion in the region of the sella turcica [13,15,26]. We endorse the view of the other authors [6,15,25,26,30] that, when the diagnosis is strongly suspected before surgery or is reached after examination of a frozen section at the time of surgery [5,15], aspiration of the cyst and partial excision of cyst wall achieves good results, as in both of our cases. Symptomatic recurrence has been encountered only in one patient 24 years after treatment [18]. A wide excision may result in possible damage to the hypothalamus and optic apparatus [ 13,15]. In recent years the transsphenoidal approach has been successfully employed in most of cases. Both of our cases were histologically classical Rathke's cleft cysts. An entirely suprasellar cyst with a normal sella turcica (patient 1) and radiologic capsular calcification in a purely Rathke's cleft cyst (patient 2) remain solitary instances in the literature for symptomatic Rathke's cleft cysts.
The authors thank Dr. M.S. Valiathan, Director of the Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, for his kind permission to publish this paper.
References l. Baldini M, Mosca L, Princi L. The empty sella syndrome secondary to Rathke's cleft cyst. Acta Neurochir 1980;53:69-78. 2. Bayoumi ML. Rathke's cleft and its cysts. Edinburg Med J 1948;55:745-9. 3. Berry RG, Schlezinger NS. Rathke's cleft cysts. Arch Neurol 1959;1:48-58. 4. Concha S, Hamilton BPM, MillanJC, McQueenJD. Symptomatic gathke's cleft cyst with amyloid stroma. J Neurol Neurosurg Psychitary 1975;38:782-6. 5. Eisenberg HM, Sarwan M, Schochet S. Symptomatic Rathke's cleft cyst. J Neurosurg 1976;45:585-8. 6. Fager CA, Carter H. lntrasellar epithelial cysts. J Neurosurg 1966;24:77-81. 7. Fairburn B, Larkin IM. A cyst of Rathke's cleft. J Neurosurg 1964;21:223-5.
Surg Neurol 1983;19:42-5
45
8. Frazier CH, Alpers BJ. Tumours of Rathke's cleft (hitherto called tumours of Rathke's pouch). Arch Neurol Psychiatry 1934;32: 973-84. 9. Holbach KH, Gullotta F. Zur Formalgenese intrasellarer and intraventrikularer Zysten. Neurochirurgia 1977;20:186-8. 10. Iraci G, Giordano R, Gerosa M, Rigobello L, Di Stefano E. Ocular involvement in recurrent cyst of Rathke's cleft--a case report. Ann Ophthalmol 1979; 11:94-98. I1. Kepes JJ. Transitional cell tumour of the pituitary gland developing from a Rathke's cleft cyst. Cancer 1978;41:337-43. 12. Leech RW, Olafson RA. Epithelial cysts of the neuraxis. Presentation of three cases and review of the origin and classification. Arch Pathol Lab Med 1977;101:196-202. 13. Martinez LJ, OsterholmJL, Berry RG, Lee KF, Schaz NJ. Transsphenoidal removal of a Rathke's cleft cyst. Neurosurgery 1979;4:63-5. 14. McGrath P. Cysts of sellar and pharyngeal hypophyses. Pathology 1971;3:123-31. 15. Nagasaka S, Kuromatsu C, Wakisaka S, Kitamura K, Matsushima T. Rathke's cleft cyst. Surg Neurol 1981;15:402-5. 16. Naiken VS, Tellem M, Meranze DR. Pituitary cyst of Rathke's cleft origin with hypopituitarism. J Neurosurg 196 I; 18:703-6. 17. Obenchain TG, Becker DP. Abscess formation in a Rathke's cleft cyst. J Neurosurg 1972;36:359-62. 18. Raskind R, Brown HA, Mathis J. Recurrent cyst of the pituitary. J Neurosurg 1968;28:595-9. 19. Ringet SP, Bailey OT. Rathke's cleft cyst. J Neurol Neurosurg Psychiatry 1972;35:693-7. 20. Russell DS, Rubinstein LJ. Pathology of tumours of the nervous system. 4th ed. Baltimore: Williams & Wilkins, 1977:32-8. 21. Saito Y, Nakaya Y, Takami M. Pituitary cyst--case report. No Shinkei Geka 1979;7: 119-24. 22. Shanklin WM. On the presence of cysts in the human pituitary. Anat Rec 1949;104:379-407. 23. Shanklin WM. Incidence and distribution of cilia in the human pituitary with a description of micro-follicular cysts derived from Rathke's cleft. Acta Anat 1951 ; 11:36 l-82. 24. Shuangshoti S, Netsky M, Nashold BS, Jr. Epithelial cyst related to the sella turcica. Proposed origin from neuroepithelium. Arch Pathol 1970;90:444-50. 25. Smith RA, Bucy PC. Pituitary cyst lined with a single layer of columnar epithelium. J Neurosurg 1953;1{):540-3. 26. Steinberg GK, Koenig GH, Golden JB. Symptomatic Rathke's cleft cysts. J Neurosurg 1982;56:290-5. 27. Verkijk A, Bots GT. An intrasellar cyst with both Rathke's cleft and epidermoid characteristics. Acta Neurochir 1980;51:203-7. 28. Worster Drought C, Dickson WEC, Archer BWC. Dyspituitarism of the Lorain type, associated with a pituitary cyst arising from Rathke's cleft and secondary lesions in hypothalamic region and ventricles. Brain 1927;50:704-18. 29. Yamakawa Y, Kinoshita K, Matsushima T. A case of Rathke's cleft cyst. Rinsho Shinkeigaku 1980;20:477. 30. YoshidaJ, Kobayashi T, Kageyama N, Kanzaki M. Symptomatic Rathke's cleft cyst. J Neurosurg 19v7;47:451-8.
Surg Neurol 1983;19:42-5
Symptomatic Rathke's Cleft Cysts D. Rout, L. Das, V.R.K. Rao, and V.V. Radhakrishnan Departments of Neurosurgery, Neuroradiology, and Neuropathology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, Kerala, India
Rout D, Das L, Rao VRK, Radhakrishnan VV. Symptomatic Rathke's cleft cysts. Surg Neurol 1983;19:42-5. T w o unusual cases of symptomatic Rathke's cleft cysts are reported. In one, the cyst was entirely supraseUar with a normal sella turcica. The gross visual failure, hypothalamic disturbances, and hypopituitarism of the patient resolved after a transfrontal aspiration and partial excision of the wall of the cyst. The second patient was a pituitary dwarf with hypothalamic dysfunction, but with normal vision. The patient had a large intrasellar cyst that exhibited marked suprasellar extension with calcification of the capsular rim. After transsphenoidal aspiration and partial excision of the wall of the cyst, the patient achieved a satisfactory recovery. The differential features between Rathke's cleft cyst and craniopharyngioma are highlighted. KEYWORDS: Rathke's cleft cyst; Suprasellar cyst; Ciliated epithelium; Craniopharyngioma
Rathke's cleft cysts are assumed to develop from remnants o f Rathke's pouch, an invagination of the stom o d e u m [3,22,23,30]. These cysts are characteristically lined by columnar or cuboidal epithelium, often with cilia and goblet cells [3,11,20,30]. Although asymptomatic Rathke's cleft cysts are relatively c o m m o n (they are found in 1 3 % - 2 2 % of all cases at autopsy [2,14,22,23]), only 61 cases of symptom-producing cysts have been reported in the literature [1,9-11,13,15, 21,26,27,29,30]. Most o f the reported symptomatic Rathke's cleft cysts are intrasellar and have caused hypopituitarism and headache in the patient. One-third of Rathke's cleft cysts, however, do have a c o m p o n e n t o f significant suprasellar extension, which produces chiasmal compression, hypothalamic dysfunction, a n d - - r a r e l y - - o b s t r u c t i v e hydrocephalus. Occasionally they may present with features of aseptic meningitis [26,27]. Chronic inflammation with abscess formation in a Rathke's cleft cyst is docu-
Address reprint requests to." Dr. D. Rout, Department of Neurosurgery, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum-695011, Kerala, India.
© 1983 by ElsevierSciencePublishingCo., Inc.
mented in one case [ 17]. H o w e v e r , entirely suprasellar symptomatic Rathke's cleft cyst with normal sella turcica is extremely uncommon. Yoshida et al [30], in a review of 35 cases o f symptomatic Rathke's cleft cyst reported through 1977, recorded a suprasellar location in five cases, although none of them had a normal sella turcica. Calcification in a Rathke's cleft cyst with a single epithelial lining, to our knowledge, is not reported in the literature, although mixed forms of Rathke's cleft cyst and craniopharyngioma are described on histologic grounds [11,27]. This paper describes two rare cases of symptomatic Rathke's cleft cyst. In one, the cyst was entirely suprasellar with a normal sella turcica causing marked chiasmal compression in addition to hypopituitarism and hypothalamic disturbances; and in the other, it was a large intrasellar cyst with marked suprasellar extension with calcification o f the capsular rim presenting with headache, panhypopituitarism, and hypothalamic dysfunction but no visual symptoms. Both cases were treated surgically with good results.
Case R e p o r t s Case I
A 19-year-old girl was referred to us in August 1981 with a history of headache and vomiting for 1.5 years, hypothalamic disturbances in the form of lethargy, hyperhydrosis, polyuria, and polydypsia for 1 year, amenorrhea for 6 months, and progressive visual failure for 4 months. She had bilateral primary optic atrophy with no vision in the left eye and a temporal field cut in the right eye; her visual acuity was 3/60. A clinical diagnosis of a suprasellar mass, probably a craniopharyngioma, was made. X-ray examination of the skull showed a normal sella turcica (Figure 1), and an angiogram of the left carotid artery with cross compression revealed a suprasellar mass (Figure 2). A craniotomy of the right frontotemporal lobe revealed a greyish-white suprasellar cyst with a moderately thick capsule over which the optic nerves and chiasm were markedly stretched. N e e d l e aspiration obtained 8 10 cm 3 of yellowish, pultaceous material; the cyst wall collapsed after the aspiration and could be freed from 0090-3019/83/010042-04503.00
Rathke's Cleft Cysts
Surg Neurol 1983;19:42-5
4
cleft cyst was made. The bacterial culture of the cystic contents did not grow any organism. The period after surgery was uneventful. Her vision improved rapidly and she was discharged with 1/60 vision in the left eye and 6/60 in the right, with an improvement in her visual fields. On examination after 6 months, her vision had improved remarkably, and she was able to perform her household duties normally. However, the amenorrhea had persisted. Case 2
the optic apparatus. A subtotal excision of cyst wall was achieved, leaving a small portion adherent to the hypothalamic region and to the planum sphenoidale anteriorly. Histologically, the cyst wall was composed of a single layer of ciliated columnar epithelium supported on a collagenous connective tissue stroma (Figure 3). The luminal surface of the cyst was heavily infiltrated with chronic inflammatory cells. Cyst fluid on smear examination revealed amorphous periodic acid-Schiffpositive material. No cholesterol crystals, keratin, or calcific changes were identified. A histologic diagnosis of Rathke's
A 20-year-old girl presented in March 1980 with a history of retarded physical development for 10 years, occasional headaches, loss of appetite, and easy fatiguability for 4 years and repeated episodes of transient loss of consciousness for 1 year; there were no visual symptoms. She was a classical pituitary dwarf, and she had thin, shiny, hairless skin. She also had undeveloped breasts and other secondary sexual characters; she had not attained menarche. There were no other neurologic deficits. X-ray examination of the skull showed a markedly enlarged sella turcica with a rim of suprasellar calcification. An angiogram of the right carotid artery showed an opening of the carotid siphon. A pneumoencephalogram confirmed an intrasellar mass with suprasellar extension elevating the floor of the anterior third ventricle (Figure 4). An orbital venogram showed definite parasellar extension. Transsphenoidal aspiration produced 7 cm ~ of thick mucoid brownish fluid; after aspiration the suprasellar calcification was reduced by 1.5 cm. Her headache and vomiting lessened, and she was discharged with advice to attend the endocrinology clinic for study. She re-
Figure 2. Patient 1: Arteriogram of the left carotid artery with cross
Figure 3. Patient 1." Photomicrograph of the cyst wall showing single layer of ciliated columnar epithelium with attenuation (H & E; × 110L
~iii~i,i,,~i~i~¸
Figure 1. Patient 1: Lateral view of the skull showing normal sella turcica.
compression showing midline suprasellar mass.
44
Surg Neurol 1983;19:42-5
Figure 4. Patient 2: Pneumoencephalogram showing enlarged sella turcica and suprasellar extension of the cyst with capsular rim calcification.
turned 4 months later complaining of recurrent headaches and vomiting; a conray ventriculogram revealed a recurrence o f the cyst indenting the floor of the anterior third ventricle. Brownish cystic fluid was aspirated through a transsphenoidal approach and the shining cyst wall was partially excised. Histopathologic examination revealed a cyst lined by cuboidal or low columnar epithelium with goblet cells, supported on a thin basement membrane. There was no evidence of stratification or keratinization in the cyst wall. The histologic features were consistent with a Rathke's cleft cyst. H e r treatment after surgery was uneventful. She made a satisfactory symptomatic improvement and was discharged on a regimen of hormonal replacement. T h e r e has been no symptomatic recurrence since the last operation. Discussion More frequent reports in recent literature indicate that symptomatic Rathke's cleft cysts are more common than suspected [26]. Since 1913 when Goldzieher described the first case, 61 cases have been reported in the literature, of which at least 36 were diagnosed at operation [1,3,5,9-11,13,15,17,18,21,25-27,29,30]. Generally these cysts are intrasellar with or without suprasellar extension. Entirely suprasellar location of the cyst with a normal sella turcica, like that of our first patient, is extremely uncommon. In a review of 35 cases, Yoshida et al [30] recorded supraseUar cysts in five of them.
Rout et al
Although there is no mention about the sella turcica in two cases, it was abnormal in the other three. Interestingly, the cyst was intrasphenoidal in one. Intrasellar epithelial cysts derived from remnants of Rathke's pouch with a lining of columnar or cuboidal cells, often with cilia and goblet cells, are called Rathke's cleft cysts [2-4,7,8,19]. However, pituitary [16,18,25,28], colloid [9], and intrasellar epithelial [6,24] cysts have been used as synonyms. Some authors believe that these cysts may arise from neuroepithelium [4,24] or by reverse metaplasia from anterior pituitary cells [ 16]. Both Rathke's cleft cyst and craniopharyngioma have a common origin: the remnants of Rathke's pouch. But they have different histologic differentiations [30]. Craniopharyngiomas are derived from squamous cell rests of the craniopharyngeal duct [20,26]. These are primarily suprasellar neoplasms that exhibit frequent radiologic calcification and contrast-medium enhancement on computed tomography scans. They also often have a cystic component with thick brown or greenish fluid resembling machine oil and are lined by stratified squamous epithelium that shows frequent keratinization. Conversely, Rathke's cleft cysts are primarily intrasellar, nonneoplastic lesions that do not exhibit radiologic calcification (in contrast to our patient 2) or contrast-medium enhancement on computed tomography scans [3,6,11,13,15,20,26,30]. These cysts are characteristically lined by ciliated columnar or cuboidal epithelium and often have mucus-secreting cells without any evidence of keratinization [3,6,11,13,20,26,30]. Whereas radical excision or partial removal followed by radiation therapy has been widely recommended for craniopharyngiomas in order to avoid recurrence, simple aspiration or partial excision of the cyst wall has been advocated for symptomatic Rathke's cleft cysts [6,13,15,25,26,30]. Rathke's cleft cysts may, however, rarely have small foci of squamous epithelia even with keratinization [3,8,11,12,20,24,26,27,30]. Solid components that have been described as pituitary adenomas [9,24], transitional cell tumors o f the pituitary [ 11], or simple tumor nodules [30] have been described in five cases of symptomatic Rathke's cleft cyst, of which three with stratified squamous epithelial lining had symptomatic recurrence after partial removal [3,10,18,26,30]. These are considered as mixed forms of craniopharyngioma and Rathke's cleft cyst, and they are neoplastic in their behavior [30]. Existence o f mixed forms of Rathke's cleft cyst and of craniopharyngioma has also been demonstrated by others [11,27]. The fluid of the Rathke's cleft cyst--although often described as white m u c o i d - - m a y be clear, blue, green, yellow, thick mucopurulent (as in our patient 1), and even brown, like machine oil [13,30]. Although pituitary adenoma has been the commonest preoperative diagnosis in these cases [15,30], non-
Rathke's Cleft Cysts
enhancing cysts such as cystic craniopharyngioma, cystic pituitary adenoma, cysticercosis cysts, arachnoid cyst, and epidermoid cyst are presently considered in the differential diagnosis of Rathke's cleft cyst when computed tomography scanning demonstrates a homogenous, low-density lesion in the region of the sella turcica [13,15,26]. We endorse the view of the other authors [6,15,25,26,30] that, when the diagnosis is strongly suspected before surgery or is reached after examination of a frozen section at the time of surgery [5,15], aspiration of the cyst and partial excision of cyst wall achieves good results, as in both of our cases. Symptomatic recurrence has been encountered only in one patient 24 years after treatment [18]. A wide excision may result in possible damage to the hypothalamus and optic apparatus [ 13,15]. In recent years the transsphenoidal approach has been successfully employed in most of cases. Both of our cases were histologically classical Rathke's cleft cysts. An entirely suprasellar cyst with a normal sella turcica (patient 1) and radiologic capsular calcification in a purely Rathke's cleft cyst (patient 2) remain solitary instances in the literature for symptomatic Rathke's cleft cysts.
The authors thank Dr. M.S. Valiathan, Director of the Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, for his kind permission to publish this paper.
References l. Baldini M, Mosca L, Princi L. The empty sella syndrome secondary to Rathke's cleft cyst. Acta Neurochir 1980;53:69-78. 2. Bayoumi ML. Rathke's cleft and its cysts. Edinburg Med J 1948;55:745-9. 3. Berry RG, Schlezinger NS. Rathke's cleft cysts. Arch Neurol 1959;1:48-58. 4. Concha S, Hamilton BPM, MillanJC, McQueenJD. Symptomatic gathke's cleft cyst with amyloid stroma. J Neurol Neurosurg Psychitary 1975;38:782-6. 5. Eisenberg HM, Sarwan M, Schochet S. Symptomatic Rathke's cleft cyst. J Neurosurg 1976;45:585-8. 6. Fager CA, Carter H. lntrasellar epithelial cysts. J Neurosurg 1966;24:77-81. 7. Fairburn B, Larkin IM. A cyst of Rathke's cleft. J Neurosurg 1964;21:223-5.
Surg Neurol 1983;19:42-5
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