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Spinal intradural arachnoid cyst
Spinal lntradural Arachnoid Cyst Renato J. Galzio, M.D., Massimo Zenobii, M.D., Danilo Lucantoni, M.D., and Luigi Cristuib-Grizzi, M.D.
A case of spinal intradural arachnoid cyst is presented, and the literature dealing with this rare lesion is surveyed. The etiological and pathological features are discussed; emphasis is placed on the importance of a correct interpretation of clinical and radiological findings that may be diagnostically misleading. Galzio RJ, ZenobiiM. LucantoniD. CristuibGrizzi: Spinal intradural arachnoidcyst. Surg Neurol 17:388-391, 1982 Intradural arachnoid cysts are among the rarest causes of spinal cord compression: only 58 cases have been reported in the literature [1-34]. Most of these cysts communicate with the subarachnoid space and are, in fact, diverticula. Our report concerns the case of a true intradural arachnoid cyst located on the dorsal aspect of the lower thoracic spinal cord, causing intermittent paraparesis, which completely disappeared after surgical excision of the lesion. Case Report In January, 1980, coinciding with her first menstruation, a 13-year-old girl started to complain of numbness in her left leg. Later, similar sensations developed in her right leg, followed by a progressive weakness of both legs. In June, 1980, she was admitted to the neurological department of another hospital. Examination revealed a marked spastic paraparesis, with bilateral extensor plantar responses. Bilateral ankle and knee clonus was found, and abdominal reflexes were absent. Below the T9 level, pinprick and touch perceptions were only slightly reduced and thermal sensation was normal, while vibration and position senses were markedly reduced. Sphincter function was normal. Routine laboratory studies and x-ray examination of the spine were normal. Spinal puncture disclosed normal pressure with the usual increase on jugular compression. Cerebrospinal fluid was clear and colorless, containing 0.8 white blood cells/mm a and 30 mg/dl protein; colloidal and electrophoretic reactions were normal. Electromyographic
From the Divisionof Neurosurgery,G. MazziniHospital, Teramo, Italy. Address reprint requests to Dr. RenatoGalzio, Divisionedi Neurochirurgia, Ospedale Civile G. Mazzini,Teramo64100, Italy. Keywords:arachnoidcyst;myelography;paraparesis;spinal cordcompression. 388
studies were negative, and air myelography failed to demonstrate any anomalous findings. The patient was kept in bed for a prolonged period and was treated with steroids and B-complex vitamins. After a month she experienced a remarkable relief from her symptoms and she was able to walk without difficulty; only a mild reduction of vibration and position senses was present below the hips. She was discharged with the diagnosis of demyelinating myelitis. There were no further problems until September, 1980, when the patient experienced a recurrence of symptoms and was admitted to the neurology department of another hospital. Signs and symptoms were the same as those present on the first hospitalization, and the diagnosis of probable multiple sclerosis was made. After a long period of bedrest and steroid treatment, the patient again showed an incomplete but marked recovery and was discharged. On March 9, 1981, the girl (then 14 years old) wa~ admitted to the Division of Neurosurgery of the G. Mazzini Hospital in Teramo due to another recurrence of symptoms. Signs and symptoms were the same as those described on the first admission. A Pantopaque (isophendylate) myelogram revealed a central defect in the column of contrast medium at the T10 to T l l level (Fig. 1), suggesting an intradural extramedullary lesion. A computerized tomographic (CT) scan demonstrated a cystic lesion at that level with the density of cerebrospinal fluid; it was situated posteriorly and was compressing the spinal cord (Fig. 2). A diagnosis of spinal intradural cyst was made. On March 16, 1981, a T9 to T l l laminectomy was performed. The dura mater, bulging and with no epidural fat, was carefully opened along the entire length of the surgical exposure. A cyst, which was the size of a small marble, was clearly visible on the posterior aspect of the spinal cord, which appeared thinned and compressed anteriorly. The surgical microscope revealed no communication between the cyst and the subarachnoid space. The cyst was totally removed; its inner wall was a direct continuation of the arachnoid sheath. The cyst was divided into two equal parts by an internal septum, and the cystic fluid was clear and colorless. The dura mater was carefully closed; at the end of the operation, it was pulsating regularly. Histological studies revealed that both the cyst wall and the septum were composed of thick arachnoid tissue with no evidence of inflammation.
0090-3019/82/050388-04501.25 © 1981 by Little, Brown and Company (Inc.)
Oalzio et al: Spinal Intradural Arachnoid Cyst
389
Fig. 2. Computerized tomogram of the spine at the TIO to T! 1 level. A cyst, with tl~ density of spinal fluid, is located on the dorsal aspect of the spinal cord, Which appears thinned and anteriorly displaced.
Fig. 1. Preoperative myelogram demonstrating a central defect in the column of oily contrast medium at the TIO to T11 level.
A week after the operation, the patient was able to walk without aid. A postoperative myelogram revealed no abnormalities at the level of the operation (Fig. 3). When she was discharged on March 28, 1981, touch and pinprick sensations were normal, but vibration and position senses were impaired below the knees; there was a marked hyperreflexia of the legs with no Babinski sign. Neurological examinations performed in September, 1981, were completely normal. Discussion Perineural, extradural, and subdural arachnoid cysts are rare causes of spinal cord or nerve root dysfunction. Although these cysts share some histological and pathogenetic features [4, 8, 16, 28, 34], they have quite different clinical manifestations, related to the different anatomical locations. Intradural spinal arachnoid cysts are less common than extradural ones [6, 16, 21, 34]. Lombardi and Morello [16], in a series of 290 surgically treated spinal lesions, found 14 arachnoid cysts--10 perineural, 3 extradural, and only 1 intradural.
In our study of the current literature, we found 58 cases of spinal intradural arachnoid cysts; 32 of them occurred in females and 26 in males. They most commonly manifested signs and symptoms during adolescence or early adult life: 27 patients were operated upon before the age of 20, and many of the patients, operated upon when older, had complained of related symptoms since youth. Forty-four of the 58 cysts were found in the thoracic region of the spinal cord; 42 were posterior to the cord, and 2 were anterior [21, 23]. Six cysts were found on the frontal aspect of the high cervical spinal cord, from C1 to C4 [6, 10, 11, 15, 20], while 3 posteriorly located cysts were found in the lower cervical spine, from C6 to C7 [7]. There were only 5 cysts in the lumbar region [4, 6, 8, 25, 31]. Cysts may be single, involving one or two spinal segments, or multiple and involving many levels. Like true diverticula, most of the cysts communicated with the subarachnoid space; noncommunicating cysts are more rare. Histological studies of excised cysts usually reveal normal arachnoid structure; sometimes, as in our patient, thickening of the fibrous tissue is present. Round-cell infiltration and other inflammatory changes are rarely seen [6, 8, 20, 28]. Most authors consider this lesion to be congenital in origin. That such cysts occur together with other congenital malformations (such as spina bifida, at a different level) supports this hypothesis, although the association is less frequent for intradural than for extradura! spinal cysts [6, 15, 16, 26, 31]. Aarabi and co-workers [1] described 2 cases
390
SurgicalNeurology Vol 17 No 5 May 1982
Fig. 3. Postoperative myelogram demonstrating free passage of oily contrast medium at the TIO to T11 level.
patient has been in an erect position for a prolonged period, the cyst fills more easily and may produce not only local compression, but also traction due to gravitational force [6, 19, 21]. Thus, rest periods with the patient in a recumbent position usually provide temporary relief from the symptoms. The intermittency of symptoms may lead to errors in diagnosis by suggesting degenerative myelitis [2, 18, 21], as occurred in our patient. When the cyst is located at the cervical level, it produces a syndrome that may be mistaken for syringomyelia [10, 11, 20]. Differentiating such cysts from other spinal cord lesions is difficult, and the diagnosis must be supported by radiological investigations. Results of laboratory studies on cerebrospinal fluid only reflect the extent of the block caused by the cyst, and in most cases they are negative. Although in rare instances scalloping of vertebrae [4, 8], spina bifida occulta [6, 15, 16, 26, 31], or kyphosis [8, 15] is associated with intradural leptomeningeal cysts, usually no bony vertebral defect is to be found on plain roentgenograms of the spine. Scintimyelography may be positive in the case of a spinal intradural cyst [4, 9]. Pantopaque myelography, performed with the patient both prone and erect, may permit a conclusive preoperative diagnosis when the cyst communicates with the subarachnoid space: Pantopaque fills the cyst when the patient is in the erect position and characteristically gives a fluid/contrast level [6, 8, 13, 17, 33]. Myelography with metrizamide, which mixes homogeneously with spinal fluid [32], can easily fail to show a communicating spinal arachnoid cyst, while air myelography may reveal the presence of a gross lesion without defining its nature [33]. With noncommunicating cysts, particularly small ones (as in our patient), Pantopaque myelography permits only a suspected diagnosis [33]. With total-body computerized tomography at high resolution, diagnosis is easier: on CT scans the cyst appears as a well-defined lesion with the density of cerebrospinal fluid [6]. In our patient only the combination of Pantopaque myelography (which revealed the level of the lesion) and the CT scan (which confirmed its cystic nature) permitted a definite preoperative diagnosis. Theoretically, spinal intradural arachnoid cysts are best treated by total surgical removal. This, however, may be hazardous, particularly when the cyst is located on the anterior aspect of the spinal cord in the cervical region. In such cases a lasting cure can be effected by marsupializing the cyst [20, 21]. In 1 case in which a cyst recurred, a shunt procedure was used [14]. Recovery from neurological deficits depends on the length and severity of the preoperative compression of the spinal cord [21].
of familial spinal intradural arachnoid cysts that demonstrated a mendelian-dominant inheritance. Teng and Papatheodorou [29] suggested that such cysts might result from defects in the distribution of arachnoid trabeculae. Perret and associates [22] postulated an origin in the septum posticum, but this hypothesis may not explain cysts located anterior to the spinal cord. Arachnoiditis due to inflammation [5, 12, 13, 15, 26], trauma [7, 17, 27], or parasitic infestation [24] is also discussed as a possible cause. Clinical signs and symptoms of spinal intradural arachnoid cysts are the same as for other space-occupying lesions in similar locations. Direct compression or traction by the cyst on the spinal cord, as well as interference with the blood supply to the spinal cord, causes the symptoms [8]. Spastic paraparesis, paresthesias, hypesthesias, pain, and disturbances in sphincter function are the most common initial complaints. Patients with such cysts frequently References 1. Aarabi B, PasternakG, Hurko O, Donlin ML: Familialintradural experience symptoms only intermittently, with remissions arachnoidcysts.Reportof two cases. J Neurosurg50:826-829, 1979 and exacerbations related to posture; this may be explained 2. AdamsRD: Case recordsof the MassachusettsGeneral Hospital. N by the repeated emptying and filling of the cyst. After the Engl J Med 293:33-38, 1975
Galzio et al: Spinal Intradural Arachnoid Cyst
3. Adams RD, Wegner W: Congenital cyst of the spinal meninges as cause of intermittent compression of the spinal cord. Arch Neurol Psychiatry 58:57-69, 1947 4. Bechar M, Beks JWF, Penning L: Intradural arachnoid cyst with scalloping of vertebrae in the lumbosacral region. A case report and review of the literature. Acta Neurochir (Wien) 26:275-283, 1972 5. Benini A: Chronic circumscribed adhesive and cystic spinal lepto. meningitis. Report of four cases, with special references to microsurgical treatment. Surg Neurol 1:223-228, 1973 6. Duncan AW, Hoare RD: Spinal arachnoid cysts in children. Radiology 126:423-429, 1978 7. El Mahdi MA: Arachnoid cyst and cord compression in association with tangential shrapnel injuries of the spine. Neurochirurgia (Stuttg) 20:1-7, 1977 8. Fortuna A, La Torte E, Ciappetta P: Arachnoid diverticula: a unitary approach to spinal cysts communicating with the subarachnoid space. Acta Neurochir (Wien) 39:259-268, 1977 9. Gros CM, Wakenheim A, Vrousos L, Subirana M: Scintigraphie cistemale. Acta Radiol [Diagn] (Stockh) 5:804-811, 1966 10. Herskowitz J, Bielawski MA, Venna M, Sabin TD: Anterior cervical arachnoid cyst simulating syringomyelia. A case with preceding posterior arachnoid cyst. Arch Neurol 35:57-58, 1978 11. Hoffman GT: Cervical arachnoidal cyst. Report of a 6-year-old Negro male with recovery from quadriplegia. J Neurosurg 17:327-330, 1960 12. Hoy RJ, Faulder KC: Spinal arachnoid cysts. Australas Radiol 12:344-354, 1968 13. Jacobs LG, Smith JK, Van Horn PS: Myelographic demonstration of cysts of spinal membranes. Radiology 62:215-221, 1954 14. Jensen F, Knudsen V, Troelsen S: Recurrent intraspinal arachnoid cyst treated with a shunt procedure. Acta Neurochir (Wien) 39:127-129, 1977 15. Kuhlendahl H: Spinale Arachnoidalzysten. Zentralbl Neurochir 19:198-204, 1959 16. Lombardi G, Morello G: Congenital cysts of the spinal membranes and roots. Br J Radiol 36:197-205, 1963 17. Long RW, Rachmaninoff N: Spinal adhesive arachnoiditis with cyst formation: injection during myelography. J Neurosurg 27:73-76, 1967
391
18. Meredith JM: Unusual tumors and tumor-like lesions of the spinal cord and its contents, with special reference to pitfalls in diagnosis. Va Med Mon 67:675-687, 1940 19. Nair VK, Gardner WJ: Isolated interruption ofspinothalamic tract by arachnoid cyst. Case Report. J Neurosurg 32:686-688, 1970 20. Palmer JJ: Cervical intradural arachnoid cyst in a 3-year-old child. Report of a case. Arch Neurol 31:214--215, 1974 21. Palmer JJ: Spinal arachnoid cysts. Report of six cases. J Neurosurg 41:728-735, 1974 22. Perret G, Green D, Keller J: Diagnosis and treatment of intradural arachnoid cysts of the thoracic spine. Radiology 79:424-429, 1962 23. Schisano G: Cisti aracnoidee spinali. Acta Neurol (Napoli) 16:773778, 1961 24. SkoogAL: Spinal cord compression from leptomeningeal cysts. With report of two cases. JAMA 65:394-398, 1915 25. Spiller WG, Musser JM, Martin E: A case of intradural spinal cyst with operation and recovery, with a brief report of eleven cases of tumor of spinal cord or spinal column. Trans Stud Coll Physicians Phila 25:1-18, 1903 26. Stewart DH, Red DE: Spinal arachnoid diverticula. J Neurosurg 35:65-70, 1971 27. Stookey B: Adhesive spinal arachnoiditis simulating spinal cord tumor. Arch Neurol Psychiatry 17:151-178, 1927 28. Tarlov IM: Spinal perineurial and meningeal cysts. J Neurol Neurosurg Psychiatry 33:833-843, 1970 29. Teng P, Papatheodorou C: Spinal arachnoid diverticula. Br J Radiol 39:249-254, 1966 30. Teng P, Rudner W: Multiple arachnoid diverticula. Arch Neurol 2:348-356, 1960 31. Tournoux P, Hermo JF: Pseudo-acropathie ulc6ro-mutilante et malformation kystique arachnoidienne lombaire. Neurochirurgie 16: 436-438, 1970 32. Valk J: Thoracic myelography with metrizamide. Acta Radiol [Suppl] (Stockh) 355:77-82, 1977 33. Vonofakos D, Grau H, Steudel W: Multiple spinal arachnoid cysts: the role of oily contrast medium. Surg Neurol 15:125-127, 1981 34. Wilkins RH, Odom GL: Spinal intradural cyst, in Vinken PJ, Bruyn GW (eds): Handbook of Clinical Neurology. Amsterdam: NorthHolland, 1976, Vol 20, pp 53-102
A case of spinal intradural arachnoid cyst is presented, and the literature dealing with this rare lesion is surveyed. The etiological and pathological features are discussed; emphasis is placed on the importance of a correct interpretation of clinical and radiological findings that may be diagnostically misleading. Galzio RJ, ZenobiiM. LucantoniD. CristuibGrizzi: Spinal intradural arachnoidcyst. Surg Neurol 17:388-391, 1982 Intradural arachnoid cysts are among the rarest causes of spinal cord compression: only 58 cases have been reported in the literature [1-34]. Most of these cysts communicate with the subarachnoid space and are, in fact, diverticula. Our report concerns the case of a true intradural arachnoid cyst located on the dorsal aspect of the lower thoracic spinal cord, causing intermittent paraparesis, which completely disappeared after surgical excision of the lesion. Case Report In January, 1980, coinciding with her first menstruation, a 13-year-old girl started to complain of numbness in her left leg. Later, similar sensations developed in her right leg, followed by a progressive weakness of both legs. In June, 1980, she was admitted to the neurological department of another hospital. Examination revealed a marked spastic paraparesis, with bilateral extensor plantar responses. Bilateral ankle and knee clonus was found, and abdominal reflexes were absent. Below the T9 level, pinprick and touch perceptions were only slightly reduced and thermal sensation was normal, while vibration and position senses were markedly reduced. Sphincter function was normal. Routine laboratory studies and x-ray examination of the spine were normal. Spinal puncture disclosed normal pressure with the usual increase on jugular compression. Cerebrospinal fluid was clear and colorless, containing 0.8 white blood cells/mm a and 30 mg/dl protein; colloidal and electrophoretic reactions were normal. Electromyographic
From the Divisionof Neurosurgery,G. MazziniHospital, Teramo, Italy. Address reprint requests to Dr. RenatoGalzio, Divisionedi Neurochirurgia, Ospedale Civile G. Mazzini,Teramo64100, Italy. Keywords:arachnoidcyst;myelography;paraparesis;spinal cordcompression. 388
studies were negative, and air myelography failed to demonstrate any anomalous findings. The patient was kept in bed for a prolonged period and was treated with steroids and B-complex vitamins. After a month she experienced a remarkable relief from her symptoms and she was able to walk without difficulty; only a mild reduction of vibration and position senses was present below the hips. She was discharged with the diagnosis of demyelinating myelitis. There were no further problems until September, 1980, when the patient experienced a recurrence of symptoms and was admitted to the neurology department of another hospital. Signs and symptoms were the same as those present on the first hospitalization, and the diagnosis of probable multiple sclerosis was made. After a long period of bedrest and steroid treatment, the patient again showed an incomplete but marked recovery and was discharged. On March 9, 1981, the girl (then 14 years old) wa~ admitted to the Division of Neurosurgery of the G. Mazzini Hospital in Teramo due to another recurrence of symptoms. Signs and symptoms were the same as those described on the first admission. A Pantopaque (isophendylate) myelogram revealed a central defect in the column of contrast medium at the T10 to T l l level (Fig. 1), suggesting an intradural extramedullary lesion. A computerized tomographic (CT) scan demonstrated a cystic lesion at that level with the density of cerebrospinal fluid; it was situated posteriorly and was compressing the spinal cord (Fig. 2). A diagnosis of spinal intradural cyst was made. On March 16, 1981, a T9 to T l l laminectomy was performed. The dura mater, bulging and with no epidural fat, was carefully opened along the entire length of the surgical exposure. A cyst, which was the size of a small marble, was clearly visible on the posterior aspect of the spinal cord, which appeared thinned and compressed anteriorly. The surgical microscope revealed no communication between the cyst and the subarachnoid space. The cyst was totally removed; its inner wall was a direct continuation of the arachnoid sheath. The cyst was divided into two equal parts by an internal septum, and the cystic fluid was clear and colorless. The dura mater was carefully closed; at the end of the operation, it was pulsating regularly. Histological studies revealed that both the cyst wall and the septum were composed of thick arachnoid tissue with no evidence of inflammation.
0090-3019/82/050388-04501.25 © 1981 by Little, Brown and Company (Inc.)
Oalzio et al: Spinal Intradural Arachnoid Cyst
389
Fig. 2. Computerized tomogram of the spine at the TIO to T! 1 level. A cyst, with tl~ density of spinal fluid, is located on the dorsal aspect of the spinal cord, Which appears thinned and anteriorly displaced.
Fig. 1. Preoperative myelogram demonstrating a central defect in the column of oily contrast medium at the TIO to T11 level.
A week after the operation, the patient was able to walk without aid. A postoperative myelogram revealed no abnormalities at the level of the operation (Fig. 3). When she was discharged on March 28, 1981, touch and pinprick sensations were normal, but vibration and position senses were impaired below the knees; there was a marked hyperreflexia of the legs with no Babinski sign. Neurological examinations performed in September, 1981, were completely normal. Discussion Perineural, extradural, and subdural arachnoid cysts are rare causes of spinal cord or nerve root dysfunction. Although these cysts share some histological and pathogenetic features [4, 8, 16, 28, 34], they have quite different clinical manifestations, related to the different anatomical locations. Intradural spinal arachnoid cysts are less common than extradural ones [6, 16, 21, 34]. Lombardi and Morello [16], in a series of 290 surgically treated spinal lesions, found 14 arachnoid cysts--10 perineural, 3 extradural, and only 1 intradural.
In our study of the current literature, we found 58 cases of spinal intradural arachnoid cysts; 32 of them occurred in females and 26 in males. They most commonly manifested signs and symptoms during adolescence or early adult life: 27 patients were operated upon before the age of 20, and many of the patients, operated upon when older, had complained of related symptoms since youth. Forty-four of the 58 cysts were found in the thoracic region of the spinal cord; 42 were posterior to the cord, and 2 were anterior [21, 23]. Six cysts were found on the frontal aspect of the high cervical spinal cord, from C1 to C4 [6, 10, 11, 15, 20], while 3 posteriorly located cysts were found in the lower cervical spine, from C6 to C7 [7]. There were only 5 cysts in the lumbar region [4, 6, 8, 25, 31]. Cysts may be single, involving one or two spinal segments, or multiple and involving many levels. Like true diverticula, most of the cysts communicated with the subarachnoid space; noncommunicating cysts are more rare. Histological studies of excised cysts usually reveal normal arachnoid structure; sometimes, as in our patient, thickening of the fibrous tissue is present. Round-cell infiltration and other inflammatory changes are rarely seen [6, 8, 20, 28]. Most authors consider this lesion to be congenital in origin. That such cysts occur together with other congenital malformations (such as spina bifida, at a different level) supports this hypothesis, although the association is less frequent for intradural than for extradura! spinal cysts [6, 15, 16, 26, 31]. Aarabi and co-workers [1] described 2 cases
390
SurgicalNeurology Vol 17 No 5 May 1982
Fig. 3. Postoperative myelogram demonstrating free passage of oily contrast medium at the TIO to T11 level.
patient has been in an erect position for a prolonged period, the cyst fills more easily and may produce not only local compression, but also traction due to gravitational force [6, 19, 21]. Thus, rest periods with the patient in a recumbent position usually provide temporary relief from the symptoms. The intermittency of symptoms may lead to errors in diagnosis by suggesting degenerative myelitis [2, 18, 21], as occurred in our patient. When the cyst is located at the cervical level, it produces a syndrome that may be mistaken for syringomyelia [10, 11, 20]. Differentiating such cysts from other spinal cord lesions is difficult, and the diagnosis must be supported by radiological investigations. Results of laboratory studies on cerebrospinal fluid only reflect the extent of the block caused by the cyst, and in most cases they are negative. Although in rare instances scalloping of vertebrae [4, 8], spina bifida occulta [6, 15, 16, 26, 31], or kyphosis [8, 15] is associated with intradural leptomeningeal cysts, usually no bony vertebral defect is to be found on plain roentgenograms of the spine. Scintimyelography may be positive in the case of a spinal intradural cyst [4, 9]. Pantopaque myelography, performed with the patient both prone and erect, may permit a conclusive preoperative diagnosis when the cyst communicates with the subarachnoid space: Pantopaque fills the cyst when the patient is in the erect position and characteristically gives a fluid/contrast level [6, 8, 13, 17, 33]. Myelography with metrizamide, which mixes homogeneously with spinal fluid [32], can easily fail to show a communicating spinal arachnoid cyst, while air myelography may reveal the presence of a gross lesion without defining its nature [33]. With noncommunicating cysts, particularly small ones (as in our patient), Pantopaque myelography permits only a suspected diagnosis [33]. With total-body computerized tomography at high resolution, diagnosis is easier: on CT scans the cyst appears as a well-defined lesion with the density of cerebrospinal fluid [6]. In our patient only the combination of Pantopaque myelography (which revealed the level of the lesion) and the CT scan (which confirmed its cystic nature) permitted a definite preoperative diagnosis. Theoretically, spinal intradural arachnoid cysts are best treated by total surgical removal. This, however, may be hazardous, particularly when the cyst is located on the anterior aspect of the spinal cord in the cervical region. In such cases a lasting cure can be effected by marsupializing the cyst [20, 21]. In 1 case in which a cyst recurred, a shunt procedure was used [14]. Recovery from neurological deficits depends on the length and severity of the preoperative compression of the spinal cord [21].
of familial spinal intradural arachnoid cysts that demonstrated a mendelian-dominant inheritance. Teng and Papatheodorou [29] suggested that such cysts might result from defects in the distribution of arachnoid trabeculae. Perret and associates [22] postulated an origin in the septum posticum, but this hypothesis may not explain cysts located anterior to the spinal cord. Arachnoiditis due to inflammation [5, 12, 13, 15, 26], trauma [7, 17, 27], or parasitic infestation [24] is also discussed as a possible cause. Clinical signs and symptoms of spinal intradural arachnoid cysts are the same as for other space-occupying lesions in similar locations. Direct compression or traction by the cyst on the spinal cord, as well as interference with the blood supply to the spinal cord, causes the symptoms [8]. Spastic paraparesis, paresthesias, hypesthesias, pain, and disturbances in sphincter function are the most common initial complaints. Patients with such cysts frequently References 1. Aarabi B, PasternakG, Hurko O, Donlin ML: Familialintradural experience symptoms only intermittently, with remissions arachnoidcysts.Reportof two cases. J Neurosurg50:826-829, 1979 and exacerbations related to posture; this may be explained 2. AdamsRD: Case recordsof the MassachusettsGeneral Hospital. N by the repeated emptying and filling of the cyst. After the Engl J Med 293:33-38, 1975
Galzio et al: Spinal Intradural Arachnoid Cyst
3. Adams RD, Wegner W: Congenital cyst of the spinal meninges as cause of intermittent compression of the spinal cord. Arch Neurol Psychiatry 58:57-69, 1947 4. Bechar M, Beks JWF, Penning L: Intradural arachnoid cyst with scalloping of vertebrae in the lumbosacral region. A case report and review of the literature. Acta Neurochir (Wien) 26:275-283, 1972 5. Benini A: Chronic circumscribed adhesive and cystic spinal lepto. meningitis. Report of four cases, with special references to microsurgical treatment. Surg Neurol 1:223-228, 1973 6. Duncan AW, Hoare RD: Spinal arachnoid cysts in children. Radiology 126:423-429, 1978 7. El Mahdi MA: Arachnoid cyst and cord compression in association with tangential shrapnel injuries of the spine. Neurochirurgia (Stuttg) 20:1-7, 1977 8. Fortuna A, La Torte E, Ciappetta P: Arachnoid diverticula: a unitary approach to spinal cysts communicating with the subarachnoid space. Acta Neurochir (Wien) 39:259-268, 1977 9. Gros CM, Wakenheim A, Vrousos L, Subirana M: Scintigraphie cistemale. Acta Radiol [Diagn] (Stockh) 5:804-811, 1966 10. Herskowitz J, Bielawski MA, Venna M, Sabin TD: Anterior cervical arachnoid cyst simulating syringomyelia. A case with preceding posterior arachnoid cyst. Arch Neurol 35:57-58, 1978 11. Hoffman GT: Cervical arachnoidal cyst. Report of a 6-year-old Negro male with recovery from quadriplegia. J Neurosurg 17:327-330, 1960 12. Hoy RJ, Faulder KC: Spinal arachnoid cysts. Australas Radiol 12:344-354, 1968 13. Jacobs LG, Smith JK, Van Horn PS: Myelographic demonstration of cysts of spinal membranes. Radiology 62:215-221, 1954 14. Jensen F, Knudsen V, Troelsen S: Recurrent intraspinal arachnoid cyst treated with a shunt procedure. Acta Neurochir (Wien) 39:127-129, 1977 15. Kuhlendahl H: Spinale Arachnoidalzysten. Zentralbl Neurochir 19:198-204, 1959 16. Lombardi G, Morello G: Congenital cysts of the spinal membranes and roots. Br J Radiol 36:197-205, 1963 17. Long RW, Rachmaninoff N: Spinal adhesive arachnoiditis with cyst formation: injection during myelography. J Neurosurg 27:73-76, 1967
391
18. Meredith JM: Unusual tumors and tumor-like lesions of the spinal cord and its contents, with special reference to pitfalls in diagnosis. Va Med Mon 67:675-687, 1940 19. Nair VK, Gardner WJ: Isolated interruption ofspinothalamic tract by arachnoid cyst. Case Report. J Neurosurg 32:686-688, 1970 20. Palmer JJ: Cervical intradural arachnoid cyst in a 3-year-old child. Report of a case. Arch Neurol 31:214--215, 1974 21. Palmer JJ: Spinal arachnoid cysts. Report of six cases. J Neurosurg 41:728-735, 1974 22. Perret G, Green D, Keller J: Diagnosis and treatment of intradural arachnoid cysts of the thoracic spine. Radiology 79:424-429, 1962 23. Schisano G: Cisti aracnoidee spinali. Acta Neurol (Napoli) 16:773778, 1961 24. SkoogAL: Spinal cord compression from leptomeningeal cysts. With report of two cases. JAMA 65:394-398, 1915 25. Spiller WG, Musser JM, Martin E: A case of intradural spinal cyst with operation and recovery, with a brief report of eleven cases of tumor of spinal cord or spinal column. Trans Stud Coll Physicians Phila 25:1-18, 1903 26. Stewart DH, Red DE: Spinal arachnoid diverticula. J Neurosurg 35:65-70, 1971 27. Stookey B: Adhesive spinal arachnoiditis simulating spinal cord tumor. Arch Neurol Psychiatry 17:151-178, 1927 28. Tarlov IM: Spinal perineurial and meningeal cysts. J Neurol Neurosurg Psychiatry 33:833-843, 1970 29. Teng P, Papatheodorou C: Spinal arachnoid diverticula. Br J Radiol 39:249-254, 1966 30. Teng P, Rudner W: Multiple arachnoid diverticula. Arch Neurol 2:348-356, 1960 31. Tournoux P, Hermo JF: Pseudo-acropathie ulc6ro-mutilante et malformation kystique arachnoidienne lombaire. Neurochirurgie 16: 436-438, 1970 32. Valk J: Thoracic myelography with metrizamide. Acta Radiol [Suppl] (Stockh) 355:77-82, 1977 33. Vonofakos D, Grau H, Steudel W: Multiple spinal arachnoid cysts: the role of oily contrast medium. Surg Neurol 15:125-127, 1981 34. Wilkins RH, Odom GL: Spinal intradural cyst, in Vinken PJ, Bruyn GW (eds): Handbook of Clinical Neurology. Amsterdam: NorthHolland, 1976, Vol 20, pp 53-102