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Large subpial lipoma of the dorsolumbar spinal cord in a pediatric patient
European Journal of Radiology Extra 58 (2006) 63–67
Large subpial lipoma of the dorsolumbar spinal cord in a pediatric patient Petra Braun a,∗ , Francisco Menor Serrano a , Khuram Kazmi b , Jose Joaqu´ın Alvarez-Garrijo a a
b
Department of Pediatric Radiology, La Fe Hospital, Avenida Campanar 21, 46009 Valencia, Spain Department of Radiology, New York University Medical Center, 530 First Avenue, New York, NY 10016, USA Received 14 December 2005; received in revised form 2 March 2006; accepted 3 March 2006
Abstract Background: Isolated spinal cord lipoma in the absence of congenital abnormalities is a rare cause of compressive myeloradiculopathy and accounts only for about 1% of all intraspinal tumors. We present an extensive subpial dorsolumbar spinal cord lipoma in a child with mild neurological symptoms and scoliosis. Case report: An 8-year-old female patient was transferred to our hospital for evaluation of urinary and anal sphincter dysfunction. Urinary tract ultrasound, cystography and urodynamic evaluation were normal. Spinal X-ray showed a discrete right dorsal scoliosis and a widened dorsolumbar spinal canal. Therefore, MRI was performed and an extensive subpial spinal cord lipoma (D1–L4) was diagnosed. The lesion demonstrated characteristic high signal intensity on T1- and T2-weighted images and suppression on fat saturation sequences. No contrast enhancement was seen. The patient did not have severe neurological symptoms, so conservative management was chosen. Clinical exam and MRI follow-up 2 years later were unchanged. Discussion: In children, spinal cord lipoma often presents with nonspecific symptoms such as hypotonia, retardation of ambulation or back pain. MRI is the best imaging modality for diagnosing intraspinal lipomas. Differentiation between intra- versus extramedullary lipoma is difficult. When nerve roots traversing the lipoma are observed, subpial origin can be assumed. Thus far, the questions of whether all spinal lipomas need surgery and does prophylactic surgery prevent neurological deterioration are not clearly answered. Therefore, the therapeutic approach has to be evaluated individually. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Spinal cord lipoma; Spinal cord tumor; Subpial; Magnetic resonance imaging
1. Introduction Intradural spinal lipomas usually are lumbosacral and associated with spinal dysraphism. Isolated spinal cord lipomas are uncommon and mainly located in the cervical and dorsal spine. Extensive subpial lipomas in children can present with nonspecific symptoms such as hypotonia, decreased ambulation, back pain or even compressive myelopathy. We present a child with a large dorsolumbar
∗ Corresponding author at: C/ Garb´ı 11, 46116 Masias, Moncada, Spain. Tel.: +34 679288874. E-mail address: [email protected] (P. Braun).
1571-4675/$ – see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2006.03.002
subpial spinal cord lipoma with sphincter dysfunction and scoliosis. Spinal subpial lipomas, as extensive as the one described in this case report, are very rare.
2. Case report An 8-year-old female patient was transferred to our institution for the evaluation of urinary and anal sphincter dysfunction. A physical examination revealed perineal hypoesthesia, absence of cremasteric and perianal reflexes and a mild scoliosis. Laboratory findings were normal. Urinary tract ultrasound, cystography and urodynamic evaluation were normal.
64
P. Braun et al. / European Journal of Radiology Extra 58 (2006) 63–67
Fig. 1. Spinal X-ray showing a discrete right dorsal scoliosis and a widened dorsolumbar spinal canal.
Spinal X-rays showed a discrete right dorsal scoliosis and a widened dorsolumbar spinal canal (Fig. 1). MRI (1.5 T, Siemens) demonstrated an extensive lesion within the spinal canal from D1 to L4. Caudally, the lesion got thinner and seemed to follow the filum terminale. It occupied nearly the entire spinal canal displacing the spinal cord ventrally. On MRI the lesion was well-demarcated and showed homogeneous high signal intensity on T1- and T2-weighted images (Figs. 2 and 3). There was corresponding low signal intensity on fat saturation images (Fig. 4), consistent with lipomatous tissue. No enhancement was detected on post contrast T1-weighted images with fat saturation (Fig. 5). Coronal T1weighted imaging revealed hypointense punctate nerve roots traversing the hyperintense lipoma (Fig. 6), suggesting a subpial location. The patient did not present with severe neurological symptoms. Therefore, conservative management was pursued. Clinical and MRI follow-up two years later demonstrated no significant change.
Fig. 2. Sagittal T1-weighted image (TR 560 TE 7.9) of the cervicodorsal spine shows a well delimitated, homogeneous, hyperintense mass occupying nearly completely the dorsal spinal canal, with anterior displacement and compression of the spinal cord.
3. Discussion Intraspinal lipomas are most often found in childhood. They are frequently associated with spinal dysraphism and are mainly located in the lumbosacral region [1]. Intradural lipomas without spinal dysraphism represent less than 1% of all spinal cord tumors. Excluding the lumbosacral spine, the reported distribution of lipomas is dorsal in 32% of cases, cervicodorsal in 24% and cervical in 13% [2]. Lipomas most frequently develop posteriorly in the spinal canal and their extent varies from one spinal segment to the entire spine with a mean of six segments [3]. Our patient had an extensive subpial lipoma (D1–L4) located posteriorly in the spinal canal. Inferiorly, it was in apparent continuity with the filum terminale. A filiform spinal cord was present anteriorly in an expanded spinal canal. A review of 100 cases of intradural spinal lipoma performed by Giuffr`e [4] showed that the second and third
P. Braun et al. / European Journal of Radiology Extra 58 (2006) 63–67
Fig. 3. Sagittal T2-weighted image (TR 3120 TE 86.9) of the lumbar spine shows a hyperintense mass occupying nearly completely the dorsolumbar spinal canal, without clearly visualizing the anteriorly displaced and compressed spinal cord, being impossible to identify the conus medullaris. The mass seems to follow the filum terminale.
decades of life accounted for 55% of all cases, followed by the first year 24% and the fifth decade 16%. There was no gender predilection. Lee et al. [5] postulated that abnormal fatty tissue may be formed during embryologic development. If a large amount of tissue has developed, the symptoms could occur at an early age. When a small ectopic island of adipose tissue has developed, the lesion may enlarge in conjunction with the general increase in adipocyte size that occurs during adult life. Thus symptoms could occur at a later age. Nonetheless, the origin of the adipocytes present in the spinal canal is not clear. Several hypotheses have been postulated but their origin still remains unknown [6]. Pierre-Kahn et al. [1] studied the behavior of adipocytes in spinal lipomas. He confirmed that the lipogenesis and lipoly-
65
Fig. 4. Sagittal T2-weighted image with fat saturation (TR 4000 TE 43.4) of the dorsal spine shows a hypointense mass occupying nearly the whole dorsal spinal canal without clearly visualizing the spinal cord, what suggests the diagnosis of an intraspinal lipoma.
sis of adipocytes in lipomas did not differ from the adipocytes of normal adipose tissue. For that reason, an increased growth rate is postulated in situations where the adipose tissue accumulates faster than other tissues, such as in neonates, adults gaining weight and during pregnancy [7]. In adults, the usual presentation is of a long indolent history followed by a more dramatic worsening over months. Local back pain, radicular pain, paraparesis, sensory disturbance, gait difficulties, incoordination, urinary incontinence and impotence have been described [5,8]. In children, spinal lipoma often presents with nonspecific symptoms such as hypotonia/floppy baby, retardation of ambulation or back pain. These may be accompanied by vertebral deformities such as kyphoscoliosis. Our patient had mild neurological symptoms and scoliosis.
66
P. Braun et al. / European Journal of Radiology Extra 58 (2006) 63–67
Fig. 5. Axial T1-weighted image with fat saturation and contrast material administration (TR 460, TE 12.2) presents a hypointense mass without enhancement, occupying nearly the whole spinal canal without clearly visualizing the spinal cord.
Plain radiographs usually are normal. Widening of the spinal canal or scalloping of the posterior margin of the vertebral bodies, as in our case (Fig. 1), may occur in large lipomas [9]. Computed tomography is often diagnostic demonstrating a lesion of fat attenuation (−30 and −140 Hounsfield units). Nevertheless, MRI is indispensable for diagnosis and preoperative evaluation of these patients. The lipomas are hyperintense on T1-weighted images and usually are hyperintense on T2-weighted images (Figs. 2 and 3). The fat-suppression sequence is very useful as it typically reduces the high signal of fatty tissue on T1- and T2-weighted images, confirming the diagnosis of lipoma (Figs. 4 and 5). Additionally, it permits a better anatomic evaluation of the lipoma in relationship to the spinal cord, especially on T2-weighted fat suppressed images (Figs. 4) [10]. Even though intraspinal lipomas usually do not enhance [11], focal areas of enhancement have been described using a fat-suppression sequence [10]. No enhancement was detected in our case (Fig. 5). The differentiation between an intradural, intramedullary and intradural extramedullary lipoma might be difficult. Nerve roots, which are seen as hypointense foci, traversing the hyperintense lipoma suggest an intramedullary location [12]. This finding was present in our patient (Fig. 6). Macroscopically, the spinal cord lipoma is a soft, yellow, fusiform tumor. Even though the edges of the lesion are often not attached to the underlying spinal cord, intraparenchymal margins are often indistinct [8]. Pathology of lipomas shows mature adipose tissue without evidence of malignancy or dedifferentiation [5]. In patients with intraspinal lipomas presenting with progressive neurological symptoms, surgery is indicated.
Fig. 6. Coronal T1-weighted image (TR 460 TE 9.6) shows hypointense puntate nerve roots traversing the hyperintense lipoma, suggesting a subpial location of the spinal cord lipoma.
However, the surgical management is still controversial. Total excision of the lipoma is seldom possible due to the lack of a clear cleavage plane between the neural and fatty tissue [13]. Severe spinal cord damage resulting in tetraplegia or death can result from attempts at complete excision of the lipoma [8,13]. Thus, the main purpose of surgery is debulking to decompress adjacent neural structures [4,7,14,15]. In the series of Ammerman et al. [8], two of seven patients with dorsal subpial lipoma underwent total excision and both developed postoperative paraplegia and incontinence. The other five patients had either biopsy and/or subtotal resection
P. Braun et al. / European Journal of Radiology Extra 58 (2006) 63–67
and showed improvement or minimal deterioration. In the opinion of Klekamp et al. [16], partial removal of the lipoma is only indicated if the spinal cord cannot be decompressed or untethered otherwise or the lipoma has increased in volume. According to Lunardi et al. [17], subtotal removal of the lipoma or simple decompression carries no higher risk of recurrence than total removal. The success of surgery depends only on the severity of the preoperative neurological deficit. Whether improvement occurs might be related to the length of time of compression, degree of disability before surgery and the type of lipoma. Lee et al. [5] presented six patients with intramedullary spinal cord lipoma who were disabled before surgery and did not improve after surgery. Therefore, they postulate that it might be advantageous to undergo early surgery in these cases in order to stabilize the clinical course [5]. Razack et al. [9] encourage early surgical debulking in all cases to prevent further progression of neurological symptoms. Unfortunately surgical outcome is generally poor. This may be due to the congenital nature of the lipoma replacing neural tissue during embryologic development. Therefore, fewer redundant spinal tracts form and subsequently the physiological reserve of the spinal cord is diminished [11]. The questions of whether every spinal lipoma needs an operation and if prophylactic surgery really prevents neurological deterioration remain controversial. The most extensive paper on this subject was published by Pierre-Kahn et al. [1] on 291 lumbosacral lipomas. They came to the conclusion that prophylactic surgery is warranted for lipomas of the filum terminale but not for lipomas attached to the conus medullaris. Surgical morbidity in the latter group was significant and beneficial effect of surgery was not confirmed during long-term follow-up. Furthermore, untethering of the spinal cord and debulking of conus lipomas did not avoid the onset of late neurological deficits in almost half of the patients. It appears reasonable to apply this conclusion for lipomas of the dorsal and cervical cord, as well [16]. This raises the question of whether the results of surgery are any better than the natural history of the disease. Since our patient presented with only mild neurological symptoms and no clinical or radiological progression during the 2-year follow-up, prophylactic surgical debulking was not performed. Ongoing MRI and clinical follow-up will be
67
carried out in order to detect any progression or complication of the spinal subpial lipoma. References [1] Pierre-Kahn A, Zerah M, Renier D. Lipomes malformatifs intrarachidiens. Neurochirurgie 1995;41(Suppl 1):1–136. [2] McGillicuddy GT, Shucart W, Kwan SE. Intradural spinal lipomas. Neurosurgery 1987;21:343–6. [3] Mrabet A, Zouari R, Mouelhi T, et al. Les lipomes intram´edullaires cervicobulbaires. A propos d’un cas avec revue de la litt´erature. Neurochirurgie 1992;38:309–14. [4] Giuffr`e R. Intradural spinal lipomas: Review of the literature (99 cases) and report of an additional case. Acta Neurochir (Wien) 1966;14:69–95. [5] Lee M, Rezai AR, Abbott R, Coelho DH, Epstein FJ. Intramedullary spinal cord lipomas. J Neurosurg 1995;82(3):394–400. [6] Kujas M, Sichez JP, Lalam TF, Poirier J. Intradural spinal lipoma of the conus medullaris without spinal dysraphism. Clin Neuropathol 2000;19(1):30–3. [7] Fujiwara F, Tamaki N, Nagashima T, Nakamura M. Intradural spinal lipomas not associated with spinal dysraphism: a report of four cases. Neurosurgery 1995;37(6):1212–5. [8] Ammerman BJ, Henry JM, De Girolami U, Earle KM. Intradural lipomas of the spinal cord: A clinicopathological correlation. J Neurosurg 1976;44:331–6. [9] Razack N, Jimenez OF, Aldana P, Ragheb J. Intramedullary holocord lipoma in an athlete: case report. Neurosurgery 1998;42(2): 394–7. [10] Kai Y, Amano T, Inamura T, et al. An infant with an intradural lipoma of the cervical spine extending into the posterior fossa. J Clin Neurosci 2003;10(1):127–30. [11] Pathi R, Kiley M, Sage M. Isolated spinal cord lipoma. J Clin Neurosci 2003;10(6):692–4. [12] Subramaniam P, Behari S, Singh Satyanarayan, Jain VK, Chhabra DK. Multiple subpial lipomas with dumb-bell extradural extension through the intervertebral foramen without spinal dysraphism. Surg Neurol 2002;11:338–43. [13] Johnson RE, Roberson GH. Subpial lipoma of the spinal cord. Radiology 1974;111:121–5. [14] Corr P, Beningfield SJ. Magnetic resonance imaging of an intradural spinal lipoma: a case report. Clin Radiol 1989;40:216–8. [15] Stolke D, Zumkeller M, Seifert V. Intraspinal lipomas in infancy and childhood causing a tethered cord syndrome. Neurosurgery 1988;11:59–65. [16] Klekamp J, Fusco M, Samii M. Thoracic intradural extramedularry lipomas. Report of three cases and review of the literature. Acta Neurochir (Wien) 2001;143(8):767–73. [17] Lunardi P, Missori P, Ferrante L, Fortuna A. Long-term results of surgical treatment of spinal lipomas. Report of 18 cases. Acta Neurochir (Wien) 1990;104:64–8.
Large subpial lipoma of the dorsolumbar spinal cord in a pediatric patient Petra Braun a,∗ , Francisco Menor Serrano a , Khuram Kazmi b , Jose Joaqu´ın Alvarez-Garrijo a a
b
Department of Pediatric Radiology, La Fe Hospital, Avenida Campanar 21, 46009 Valencia, Spain Department of Radiology, New York University Medical Center, 530 First Avenue, New York, NY 10016, USA Received 14 December 2005; received in revised form 2 March 2006; accepted 3 March 2006
Abstract Background: Isolated spinal cord lipoma in the absence of congenital abnormalities is a rare cause of compressive myeloradiculopathy and accounts only for about 1% of all intraspinal tumors. We present an extensive subpial dorsolumbar spinal cord lipoma in a child with mild neurological symptoms and scoliosis. Case report: An 8-year-old female patient was transferred to our hospital for evaluation of urinary and anal sphincter dysfunction. Urinary tract ultrasound, cystography and urodynamic evaluation were normal. Spinal X-ray showed a discrete right dorsal scoliosis and a widened dorsolumbar spinal canal. Therefore, MRI was performed and an extensive subpial spinal cord lipoma (D1–L4) was diagnosed. The lesion demonstrated characteristic high signal intensity on T1- and T2-weighted images and suppression on fat saturation sequences. No contrast enhancement was seen. The patient did not have severe neurological symptoms, so conservative management was chosen. Clinical exam and MRI follow-up 2 years later were unchanged. Discussion: In children, spinal cord lipoma often presents with nonspecific symptoms such as hypotonia, retardation of ambulation or back pain. MRI is the best imaging modality for diagnosing intraspinal lipomas. Differentiation between intra- versus extramedullary lipoma is difficult. When nerve roots traversing the lipoma are observed, subpial origin can be assumed. Thus far, the questions of whether all spinal lipomas need surgery and does prophylactic surgery prevent neurological deterioration are not clearly answered. Therefore, the therapeutic approach has to be evaluated individually. © 2006 Elsevier Ireland Ltd. All rights reserved. Keywords: Spinal cord lipoma; Spinal cord tumor; Subpial; Magnetic resonance imaging
1. Introduction Intradural spinal lipomas usually are lumbosacral and associated with spinal dysraphism. Isolated spinal cord lipomas are uncommon and mainly located in the cervical and dorsal spine. Extensive subpial lipomas in children can present with nonspecific symptoms such as hypotonia, decreased ambulation, back pain or even compressive myelopathy. We present a child with a large dorsolumbar
∗ Corresponding author at: C/ Garb´ı 11, 46116 Masias, Moncada, Spain. Tel.: +34 679288874. E-mail address: [email protected] (P. Braun).
1571-4675/$ – see front matter © 2006 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.ejrex.2006.03.002
subpial spinal cord lipoma with sphincter dysfunction and scoliosis. Spinal subpial lipomas, as extensive as the one described in this case report, are very rare.
2. Case report An 8-year-old female patient was transferred to our institution for the evaluation of urinary and anal sphincter dysfunction. A physical examination revealed perineal hypoesthesia, absence of cremasteric and perianal reflexes and a mild scoliosis. Laboratory findings were normal. Urinary tract ultrasound, cystography and urodynamic evaluation were normal.
64
P. Braun et al. / European Journal of Radiology Extra 58 (2006) 63–67
Fig. 1. Spinal X-ray showing a discrete right dorsal scoliosis and a widened dorsolumbar spinal canal.
Spinal X-rays showed a discrete right dorsal scoliosis and a widened dorsolumbar spinal canal (Fig. 1). MRI (1.5 T, Siemens) demonstrated an extensive lesion within the spinal canal from D1 to L4. Caudally, the lesion got thinner and seemed to follow the filum terminale. It occupied nearly the entire spinal canal displacing the spinal cord ventrally. On MRI the lesion was well-demarcated and showed homogeneous high signal intensity on T1- and T2-weighted images (Figs. 2 and 3). There was corresponding low signal intensity on fat saturation images (Fig. 4), consistent with lipomatous tissue. No enhancement was detected on post contrast T1-weighted images with fat saturation (Fig. 5). Coronal T1weighted imaging revealed hypointense punctate nerve roots traversing the hyperintense lipoma (Fig. 6), suggesting a subpial location. The patient did not present with severe neurological symptoms. Therefore, conservative management was pursued. Clinical and MRI follow-up two years later demonstrated no significant change.
Fig. 2. Sagittal T1-weighted image (TR 560 TE 7.9) of the cervicodorsal spine shows a well delimitated, homogeneous, hyperintense mass occupying nearly completely the dorsal spinal canal, with anterior displacement and compression of the spinal cord.
3. Discussion Intraspinal lipomas are most often found in childhood. They are frequently associated with spinal dysraphism and are mainly located in the lumbosacral region [1]. Intradural lipomas without spinal dysraphism represent less than 1% of all spinal cord tumors. Excluding the lumbosacral spine, the reported distribution of lipomas is dorsal in 32% of cases, cervicodorsal in 24% and cervical in 13% [2]. Lipomas most frequently develop posteriorly in the spinal canal and their extent varies from one spinal segment to the entire spine with a mean of six segments [3]. Our patient had an extensive subpial lipoma (D1–L4) located posteriorly in the spinal canal. Inferiorly, it was in apparent continuity with the filum terminale. A filiform spinal cord was present anteriorly in an expanded spinal canal. A review of 100 cases of intradural spinal lipoma performed by Giuffr`e [4] showed that the second and third
P. Braun et al. / European Journal of Radiology Extra 58 (2006) 63–67
Fig. 3. Sagittal T2-weighted image (TR 3120 TE 86.9) of the lumbar spine shows a hyperintense mass occupying nearly completely the dorsolumbar spinal canal, without clearly visualizing the anteriorly displaced and compressed spinal cord, being impossible to identify the conus medullaris. The mass seems to follow the filum terminale.
decades of life accounted for 55% of all cases, followed by the first year 24% and the fifth decade 16%. There was no gender predilection. Lee et al. [5] postulated that abnormal fatty tissue may be formed during embryologic development. If a large amount of tissue has developed, the symptoms could occur at an early age. When a small ectopic island of adipose tissue has developed, the lesion may enlarge in conjunction with the general increase in adipocyte size that occurs during adult life. Thus symptoms could occur at a later age. Nonetheless, the origin of the adipocytes present in the spinal canal is not clear. Several hypotheses have been postulated but their origin still remains unknown [6]. Pierre-Kahn et al. [1] studied the behavior of adipocytes in spinal lipomas. He confirmed that the lipogenesis and lipoly-
65
Fig. 4. Sagittal T2-weighted image with fat saturation (TR 4000 TE 43.4) of the dorsal spine shows a hypointense mass occupying nearly the whole dorsal spinal canal without clearly visualizing the spinal cord, what suggests the diagnosis of an intraspinal lipoma.
sis of adipocytes in lipomas did not differ from the adipocytes of normal adipose tissue. For that reason, an increased growth rate is postulated in situations where the adipose tissue accumulates faster than other tissues, such as in neonates, adults gaining weight and during pregnancy [7]. In adults, the usual presentation is of a long indolent history followed by a more dramatic worsening over months. Local back pain, radicular pain, paraparesis, sensory disturbance, gait difficulties, incoordination, urinary incontinence and impotence have been described [5,8]. In children, spinal lipoma often presents with nonspecific symptoms such as hypotonia/floppy baby, retardation of ambulation or back pain. These may be accompanied by vertebral deformities such as kyphoscoliosis. Our patient had mild neurological symptoms and scoliosis.
66
P. Braun et al. / European Journal of Radiology Extra 58 (2006) 63–67
Fig. 5. Axial T1-weighted image with fat saturation and contrast material administration (TR 460, TE 12.2) presents a hypointense mass without enhancement, occupying nearly the whole spinal canal without clearly visualizing the spinal cord.
Plain radiographs usually are normal. Widening of the spinal canal or scalloping of the posterior margin of the vertebral bodies, as in our case (Fig. 1), may occur in large lipomas [9]. Computed tomography is often diagnostic demonstrating a lesion of fat attenuation (−30 and −140 Hounsfield units). Nevertheless, MRI is indispensable for diagnosis and preoperative evaluation of these patients. The lipomas are hyperintense on T1-weighted images and usually are hyperintense on T2-weighted images (Figs. 2 and 3). The fat-suppression sequence is very useful as it typically reduces the high signal of fatty tissue on T1- and T2-weighted images, confirming the diagnosis of lipoma (Figs. 4 and 5). Additionally, it permits a better anatomic evaluation of the lipoma in relationship to the spinal cord, especially on T2-weighted fat suppressed images (Figs. 4) [10]. Even though intraspinal lipomas usually do not enhance [11], focal areas of enhancement have been described using a fat-suppression sequence [10]. No enhancement was detected in our case (Fig. 5). The differentiation between an intradural, intramedullary and intradural extramedullary lipoma might be difficult. Nerve roots, which are seen as hypointense foci, traversing the hyperintense lipoma suggest an intramedullary location [12]. This finding was present in our patient (Fig. 6). Macroscopically, the spinal cord lipoma is a soft, yellow, fusiform tumor. Even though the edges of the lesion are often not attached to the underlying spinal cord, intraparenchymal margins are often indistinct [8]. Pathology of lipomas shows mature adipose tissue without evidence of malignancy or dedifferentiation [5]. In patients with intraspinal lipomas presenting with progressive neurological symptoms, surgery is indicated.
Fig. 6. Coronal T1-weighted image (TR 460 TE 9.6) shows hypointense puntate nerve roots traversing the hyperintense lipoma, suggesting a subpial location of the spinal cord lipoma.
However, the surgical management is still controversial. Total excision of the lipoma is seldom possible due to the lack of a clear cleavage plane between the neural and fatty tissue [13]. Severe spinal cord damage resulting in tetraplegia or death can result from attempts at complete excision of the lipoma [8,13]. Thus, the main purpose of surgery is debulking to decompress adjacent neural structures [4,7,14,15]. In the series of Ammerman et al. [8], two of seven patients with dorsal subpial lipoma underwent total excision and both developed postoperative paraplegia and incontinence. The other five patients had either biopsy and/or subtotal resection
P. Braun et al. / European Journal of Radiology Extra 58 (2006) 63–67
and showed improvement or minimal deterioration. In the opinion of Klekamp et al. [16], partial removal of the lipoma is only indicated if the spinal cord cannot be decompressed or untethered otherwise or the lipoma has increased in volume. According to Lunardi et al. [17], subtotal removal of the lipoma or simple decompression carries no higher risk of recurrence than total removal. The success of surgery depends only on the severity of the preoperative neurological deficit. Whether improvement occurs might be related to the length of time of compression, degree of disability before surgery and the type of lipoma. Lee et al. [5] presented six patients with intramedullary spinal cord lipoma who were disabled before surgery and did not improve after surgery. Therefore, they postulate that it might be advantageous to undergo early surgery in these cases in order to stabilize the clinical course [5]. Razack et al. [9] encourage early surgical debulking in all cases to prevent further progression of neurological symptoms. Unfortunately surgical outcome is generally poor. This may be due to the congenital nature of the lipoma replacing neural tissue during embryologic development. Therefore, fewer redundant spinal tracts form and subsequently the physiological reserve of the spinal cord is diminished [11]. The questions of whether every spinal lipoma needs an operation and if prophylactic surgery really prevents neurological deterioration remain controversial. The most extensive paper on this subject was published by Pierre-Kahn et al. [1] on 291 lumbosacral lipomas. They came to the conclusion that prophylactic surgery is warranted for lipomas of the filum terminale but not for lipomas attached to the conus medullaris. Surgical morbidity in the latter group was significant and beneficial effect of surgery was not confirmed during long-term follow-up. Furthermore, untethering of the spinal cord and debulking of conus lipomas did not avoid the onset of late neurological deficits in almost half of the patients. It appears reasonable to apply this conclusion for lipomas of the dorsal and cervical cord, as well [16]. This raises the question of whether the results of surgery are any better than the natural history of the disease. Since our patient presented with only mild neurological symptoms and no clinical or radiological progression during the 2-year follow-up, prophylactic surgical debulking was not performed. Ongoing MRI and clinical follow-up will be
67
carried out in order to detect any progression or complication of the spinal subpial lipoma. References [1] Pierre-Kahn A, Zerah M, Renier D. Lipomes malformatifs intrarachidiens. Neurochirurgie 1995;41(Suppl 1):1–136. [2] McGillicuddy GT, Shucart W, Kwan SE. Intradural spinal lipomas. Neurosurgery 1987;21:343–6. [3] Mrabet A, Zouari R, Mouelhi T, et al. Les lipomes intram´edullaires cervicobulbaires. A propos d’un cas avec revue de la litt´erature. Neurochirurgie 1992;38:309–14. [4] Giuffr`e R. Intradural spinal lipomas: Review of the literature (99 cases) and report of an additional case. Acta Neurochir (Wien) 1966;14:69–95. [5] Lee M, Rezai AR, Abbott R, Coelho DH, Epstein FJ. Intramedullary spinal cord lipomas. J Neurosurg 1995;82(3):394–400. [6] Kujas M, Sichez JP, Lalam TF, Poirier J. Intradural spinal lipoma of the conus medullaris without spinal dysraphism. Clin Neuropathol 2000;19(1):30–3. [7] Fujiwara F, Tamaki N, Nagashima T, Nakamura M. Intradural spinal lipomas not associated with spinal dysraphism: a report of four cases. Neurosurgery 1995;37(6):1212–5. [8] Ammerman BJ, Henry JM, De Girolami U, Earle KM. Intradural lipomas of the spinal cord: A clinicopathological correlation. J Neurosurg 1976;44:331–6. [9] Razack N, Jimenez OF, Aldana P, Ragheb J. Intramedullary holocord lipoma in an athlete: case report. Neurosurgery 1998;42(2): 394–7. [10] Kai Y, Amano T, Inamura T, et al. An infant with an intradural lipoma of the cervical spine extending into the posterior fossa. J Clin Neurosci 2003;10(1):127–30. [11] Pathi R, Kiley M, Sage M. Isolated spinal cord lipoma. J Clin Neurosci 2003;10(6):692–4. [12] Subramaniam P, Behari S, Singh Satyanarayan, Jain VK, Chhabra DK. Multiple subpial lipomas with dumb-bell extradural extension through the intervertebral foramen without spinal dysraphism. Surg Neurol 2002;11:338–43. [13] Johnson RE, Roberson GH. Subpial lipoma of the spinal cord. Radiology 1974;111:121–5. [14] Corr P, Beningfield SJ. Magnetic resonance imaging of an intradural spinal lipoma: a case report. Clin Radiol 1989;40:216–8. [15] Stolke D, Zumkeller M, Seifert V. Intraspinal lipomas in infancy and childhood causing a tethered cord syndrome. Neurosurgery 1988;11:59–65. [16] Klekamp J, Fusco M, Samii M. Thoracic intradural extramedularry lipomas. Report of three cases and review of the literature. Acta Neurochir (Wien) 2001;143(8):767–73. [17] Lunardi P, Missori P, Ferrante L, Fortuna A. Long-term results of surgical treatment of spinal lipomas. Report of 18 cases. Acta Neurochir (Wien) 1990;104:64–8.