1991, The British Journal of Radiology, 64, 473-474
Case of the month A pearl of wisdom By J . Rawlinson, MA, FRCS, FRCR, C. L. Coblentz, M D , FRCPC and S. Franic, M D , FRCPC Department of Radiology, McMaster University Medical Centre, 1200 Main Street West, Hamilton L8N 3Z5, Ontario, Canada (Received March 1990)
An 8-year-old girl presented with progressive unsteadiness on her feet over a 2-year period. She was otherwise
fit and well. No neurological deficit was found on examination, but movements of the lumbar spine were reduced. Conventional radiographs of the lumbar spine, Address for correspondence: Dr J. Rawlinson, Fellow in myelogram and computed tomography (CT) myeloRadiology, Department of Radiology, McMaster University graphic findings are demonstrated in Figs 1-3, Medical Centre, 1200 Main Street West, Hamilton L8N 3Z5, respectively. Ontario, Canada. What is your differentia] diagnosis? What further information would you seek to clarify the diagnosis?
(a) (b) Figure 1. (a) Anteroposterior and (b) lateral conventional radiographs of the lumbar spine.
(a) Vol. 64, No. 761
(a) (b) Figure 2. Myelogram: (a) anteroposterior and (b) lateral vi views of the lumbar region.
Figure 3. Post-myelography CT: axial sections (a) through the body of L3 and (b) at the level of the L3/4 disc.
473
Case of the month
The plain radiographs of the lumbar spine show a scoliosis concave to the right and subtle scalloping of the posterior aspects of the lumbar vertebral bodies 3-5. On the anteroposterior view there is some flattening of the medial side of both L4 pedicles. There is no evidence of bone destruction, disc space narrowing or expansion of the exit foramina. The myelogram demonstrates an intradural mass composed of conglomerate nodules embedded within the cauda equina. This mass has expanded the theca and obstructed the flow of contrast in a caudal direction from the level of L3. Post-myelography CT shows the intradural lesion intimately related to the cauda equina. The mass is low in density and cannot be easily differentiated from the nerve roots. An intradural "pearly grey" mass was found at surgery. This was loosely adherent to the nerve roots of the cauda equina from which it was easily peeled. Histological examination of the excised tissue showed abundant keratin composed of stratified squamous epithelium with characteristic features of an epidermoid tumour. Following surgery the patient made a complete recovery. Discussion The differential diagnosis of an intradural mass at this site in childhood includes ependymoma of the filum terminale, lipoma, neurofibroma, metastases {e.g. medulloblastoma, neuroblastoma), dermoid/epidermoid tumour and teratoma; meningiomas may also rarely occur in childhood (Peacock & Lazareff, 1986). The plain radiographic findings and the length of the history suggest a slow growing, relatively benign lesion. Lipomas and dermoid/epidermoid tumours are usually associated with spinal dysraphism, for which there is no evidence here; neurofibromas commonly involve the exit foramina and are associated with other stigmata of neurofibromatosis. Epidermoid or "pearly" tumours of the central nervous system are rare and usually found in the posterior fossa; they are even less common in the spinal canal where they tend to occur in the lumbosacral region. In a review of 90 intraspinal epidermoid tumours (Manno et al, 1962), all were located in the lumbar region and most were in children. It is notable that 39 (43%) of these patients had been subjected to /um6ar puncture in period's ranging from tfrnonfris to 10 years prior to their presentation.
Lumbar punctures in children, particularly infants, are sometimes performed using a "butterfly" infusion needle (Halcrow et al, 1985; Ersback & Hobolth, 1988). Such unstiletted needles may collect a core of epithelial tissue during their passage through the skin (Gibson & Norris, 1958); furthermore, this tissue can implant and grow within the theca (Van Gilder & Schwartz, 1967). There is good presumptive evidence, therefore, that intraspinal epidermoid tumours may be a late complication of lumbar puncture. Normal myelograms prior to lumbar puncture in at least four of the reported cases support the hypothesis of iatrogenic implantation of epithelial cells. The relevant information which should be sought to clarify the diagnosis is a history of lumbar puncture. Our patient had undergone two lumbar punctures at the age of 4 months to investigate a neurological reaction to metoclompramide, administered for vomiting. A full recovery was made and she was subsequently well until becoming unsteady on her feet at the age of 7 years. While the incidence of iatrogenic intraspinal epidermoid tumours appears to be declining (Visciani et al, 1989), two cases have recently been reported (Ersbak & Hobolth, 1988; Visciani et al, 1989); also, a survey in 1985 (Halcrow et al, 1985) showed that 32% of paediatricians routinely use an unstiletted needle for lumbar puncture in neonates and small children. Sporadic cases are therefore likely to occur in the future and may be encountered by those involved in neuroradiology. References ERSBAK, V. & HOBOLTH, N., 1988. Iatrogenic intraspinal
epidermoid
tumour
(Short
communication).
Ada
Paediatrica Scandinavica, 77, 759. GIBSON, T. & NORRIS, W., 1958. Skin fragments removed by injection needles. Lancet, ii, 983-985. HALCROW, S. J., CRAWFORD, P. J. & CRAFT, A. W., 1985.
Epidermoid spinal tumours after lumbar puncture. Archives of Disease in Childhood, 60, 978-979. MANNO,
N. J.,
Intraspinal 754-765.
UHLETO,
A.
epidermoids.
&
KERNOHAN, J . W ,
1962.
Journal of Neurosurgery, 19,
PEACOCK, W. J. & LAZERAFF, J. A. 1986. Spinal tumours of
childhood. South African Medical Journal, 70, 668-670. VAN
GILDER, J. C. & SCHWARTZ, H. G.,
1967. Growth of
dermoids from skin implants to the nervous system and surrounding spaces of the newborn rat. Journal of Neurosurgery, 26, 14-20. VISCIANI, A., SAVOIARDO, M., BALESTRINI, M. R. & SOLERO,
C. L., 1989. Iatrogenic intraspinal epidermoid tumour: myelo-CT and MRI diagnosis. Neuroradiology, 31, 273-275.
Keywords: Epidermal cyst, Cauda equina, Iatrogenic disease
474
The British Journal of Radiology, May 1991
Case of the month A pearl of wisdom By J . Rawlinson, MA, FRCS, FRCR, C. L. Coblentz, M D , FRCPC and S. Franic, M D , FRCPC Department of Radiology, McMaster University Medical Centre, 1200 Main Street West, Hamilton L8N 3Z5, Ontario, Canada (Received March 1990)
An 8-year-old girl presented with progressive unsteadiness on her feet over a 2-year period. She was otherwise
fit and well. No neurological deficit was found on examination, but movements of the lumbar spine were reduced. Conventional radiographs of the lumbar spine, Address for correspondence: Dr J. Rawlinson, Fellow in myelogram and computed tomography (CT) myeloRadiology, Department of Radiology, McMaster University graphic findings are demonstrated in Figs 1-3, Medical Centre, 1200 Main Street West, Hamilton L8N 3Z5, respectively. Ontario, Canada. What is your differentia] diagnosis? What further information would you seek to clarify the diagnosis?
(a) (b) Figure 1. (a) Anteroposterior and (b) lateral conventional radiographs of the lumbar spine.
(a) Vol. 64, No. 761
(a) (b) Figure 2. Myelogram: (a) anteroposterior and (b) lateral vi views of the lumbar region.
Figure 3. Post-myelography CT: axial sections (a) through the body of L3 and (b) at the level of the L3/4 disc.
473
Case of the month
The plain radiographs of the lumbar spine show a scoliosis concave to the right and subtle scalloping of the posterior aspects of the lumbar vertebral bodies 3-5. On the anteroposterior view there is some flattening of the medial side of both L4 pedicles. There is no evidence of bone destruction, disc space narrowing or expansion of the exit foramina. The myelogram demonstrates an intradural mass composed of conglomerate nodules embedded within the cauda equina. This mass has expanded the theca and obstructed the flow of contrast in a caudal direction from the level of L3. Post-myelography CT shows the intradural lesion intimately related to the cauda equina. The mass is low in density and cannot be easily differentiated from the nerve roots. An intradural "pearly grey" mass was found at surgery. This was loosely adherent to the nerve roots of the cauda equina from which it was easily peeled. Histological examination of the excised tissue showed abundant keratin composed of stratified squamous epithelium with characteristic features of an epidermoid tumour. Following surgery the patient made a complete recovery. Discussion The differential diagnosis of an intradural mass at this site in childhood includes ependymoma of the filum terminale, lipoma, neurofibroma, metastases {e.g. medulloblastoma, neuroblastoma), dermoid/epidermoid tumour and teratoma; meningiomas may also rarely occur in childhood (Peacock & Lazareff, 1986). The plain radiographic findings and the length of the history suggest a slow growing, relatively benign lesion. Lipomas and dermoid/epidermoid tumours are usually associated with spinal dysraphism, for which there is no evidence here; neurofibromas commonly involve the exit foramina and are associated with other stigmata of neurofibromatosis. Epidermoid or "pearly" tumours of the central nervous system are rare and usually found in the posterior fossa; they are even less common in the spinal canal where they tend to occur in the lumbosacral region. In a review of 90 intraspinal epidermoid tumours (Manno et al, 1962), all were located in the lumbar region and most were in children. It is notable that 39 (43%) of these patients had been subjected to /um6ar puncture in period's ranging from tfrnonfris to 10 years prior to their presentation.
Lumbar punctures in children, particularly infants, are sometimes performed using a "butterfly" infusion needle (Halcrow et al, 1985; Ersback & Hobolth, 1988). Such unstiletted needles may collect a core of epithelial tissue during their passage through the skin (Gibson & Norris, 1958); furthermore, this tissue can implant and grow within the theca (Van Gilder & Schwartz, 1967). There is good presumptive evidence, therefore, that intraspinal epidermoid tumours may be a late complication of lumbar puncture. Normal myelograms prior to lumbar puncture in at least four of the reported cases support the hypothesis of iatrogenic implantation of epithelial cells. The relevant information which should be sought to clarify the diagnosis is a history of lumbar puncture. Our patient had undergone two lumbar punctures at the age of 4 months to investigate a neurological reaction to metoclompramide, administered for vomiting. A full recovery was made and she was subsequently well until becoming unsteady on her feet at the age of 7 years. While the incidence of iatrogenic intraspinal epidermoid tumours appears to be declining (Visciani et al, 1989), two cases have recently been reported (Ersbak & Hobolth, 1988; Visciani et al, 1989); also, a survey in 1985 (Halcrow et al, 1985) showed that 32% of paediatricians routinely use an unstiletted needle for lumbar puncture in neonates and small children. Sporadic cases are therefore likely to occur in the future and may be encountered by those involved in neuroradiology. References ERSBAK, V. & HOBOLTH, N., 1988. Iatrogenic intraspinal
epidermoid
tumour
(Short
communication).
Ada
Paediatrica Scandinavica, 77, 759. GIBSON, T. & NORRIS, W., 1958. Skin fragments removed by injection needles. Lancet, ii, 983-985. HALCROW, S. J., CRAWFORD, P. J. & CRAFT, A. W., 1985.
Epidermoid spinal tumours after lumbar puncture. Archives of Disease in Childhood, 60, 978-979. MANNO,
N. J.,
Intraspinal 754-765.
UHLETO,
A.
epidermoids.
&
KERNOHAN, J . W ,
1962.
Journal of Neurosurgery, 19,
PEACOCK, W. J. & LAZERAFF, J. A. 1986. Spinal tumours of
childhood. South African Medical Journal, 70, 668-670. VAN
GILDER, J. C. & SCHWARTZ, H. G.,
1967. Growth of
dermoids from skin implants to the nervous system and surrounding spaces of the newborn rat. Journal of Neurosurgery, 26, 14-20. VISCIANI, A., SAVOIARDO, M., BALESTRINI, M. R. & SOLERO,
C. L., 1989. Iatrogenic intraspinal epidermoid tumour: myelo-CT and MRI diagnosis. Neuroradiology, 31, 273-275.
Keywords: Epidermal cyst, Cauda equina, Iatrogenic disease
474
The British Journal of Radiology, May 1991
