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Giant intrasacral schwannoma: an unusual cause of lumbrosacral radiculopathy
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Giant Intrasacral Schwannoma: An Unusual Cause of Lumbrosacral Radiculopathy Jackson B. Salvant, Jr., M.D., and Harold F. Young, M.D. Medical College of Virginia, Richmond
Tumors involving the sacral spine are uncommon. These lesions should be considered in the differential diagnosis of lumbrosacral radiculopathy. Tumors in the sacrum can grow large while producing minimal symptoms. A recent case of sacral schwannoma (SS) treated at our institution is presented.
prick hypesthesia was noted over the left heel and the left Achilles's tendon reflex was diminished. Plain radiographs of the spine revealed a large lucent area in the left sacral ala that extended to the sacro-iliac joint (Figure 1). Magnetic resonance imaging (MRI) of the lumbar spine and sacrum confirmed a large homogeneous tumor within the sacrum, displacing the caudal theca and nerve roots (Figures 2 and 3). The patient underwent surgery via posterior sacral laminectomy and a large tumor attached to the left first sacral root was entirely removed. This required decompression of the sacral spinal canal and removal of additional bone over the lateral extent of the tumor. After identifying the caudal thecal sac, nerve roots were followed distally and carefully separated from the mass by microdissection. The dura was opened and internal decompression of the mass allowed for separation of the tumor. Pathologic examination revealed benign schwannoma (Figure 4). At 18 months follow-up, the patient is fully ambulatory and continent with no residual weakness. Mild pinprick hypesthesia in the first sacral dermatome persists.
Case R e p o r t
Discussion
A 32-year-old man noticed gradual low back pain extending into the left leg 2 weeks after lifting a heavy object. The pain was moderately severe and nearly constant, occasionally sharp in nature. Pain was present down the posterior aspect of the thigh and lower leg. Postural changes or Valsalva did not influence the extent or character of his pain. There were no complaints of weakness, bowel or urinary incontinence, or constipation. No changes in sensation were noted by the patient. Prior medical history was unremarkable. Examination of the spine was normal. Straight leg raising was normal. Motor strength was normal. Pin-
Less than 1% of all spinal schwannomas occur in the sacrum [1]. The differential diagnosis of these lesions is extensive, and radiography may not provide sufficient information for diagnosis in some cases. There are 23 previously reported cases of sacral schwannoma--the largest single series, which included 13 cases, is from the Mayo clinic [1]. To these we add our case. Most patients experience sciatica (79%), back pain (58%), or reflex changes (50%). Some patients experienced longstanding symptoms ranging up to 23 years. At diagnosis, patients ranged from 12 to 57 years of age, mean 35.2; 54% were male and 46% female. No patients had neurofibromatosis.
Address reprint requests to: Jackson B. Salvant, Jr., M.D., Division of Neurosurgery, Box 631, MCV Station, Richmond, VA 23298. Received August 9, 1993; accepted September 22, 1993.
Radiographic Evaluation
Salvant Jr JB, Young HF. Giant intrasacral schwannoma: an unusual cause of lumbosacral radiculopathy. Surg Neurol 1994;41:411-2.
Sacral schwannoma is a rare lesion (23 reported cases) with a tendency to reach large proportions. Symptoms are back and leg pain, leg weakness, hypoesthesias, paresthesias, constipation, and incontinence. The peak incidence is between ages 30 and 50. Radiographs of the sacrum are abnormal in nearly all cases. Computed tomography and magnetic resonance imaging may reveal large lesions with bony erosion and involvement of the soft tissues. The treatment of this lesion is complete removal, which is curative. KEYWORDS" Sacrum; Schwannoma; Sciatica; Tumor
© 1994 by ElsevierScienceInc.
Radiographic studies are vital to evaluation of these patients and a variety of examinations may be necessary o090-%019/94/$7.00
412
Surg Neurol 1994;41:411-3
Figure 1. Plain Radiograph. Lucency within the sacrum (arrows) can be
Salvant and Young
Figure 3. This axial M R image demonstrates the large tumor involving most of the left sacrum (small arrows). The right side of the sacrum (arrowhead) is preserved.
seen.
to adequately define the extent of the tumor. Plain radiographs demonstrated a lesion in 21 reported cases and were the sole preoperative study in three cases prior to the availability of computed tomography (CT). CT and MRI provide information regarding involvement of the spine, nerve roots, and retroperitoneum and may
exclude some processes in the differential diagnosis. Additional studies including myelography, barium enema, and intravenous urogram may also be indicated.
Pathologic Characteristics Pathologic features of these lesions are well-known and have been extensively described [2]. These lesions can involve retroperitoneal vascular structures and hollow organs. Grossly, the tumors are found to be firm and well-encapsulated and may be easily separated from adjacent bony structures. This characteristic often makes
........
.~
.
~ .
Figure 2. The extent of sacral involvement and displacement of the thecal sac can be seen in this T2-weighted sagital M R image demonstrating the mass filling the spinal canal and extending into the sacrum with a clear demarcation between tumor and bone.
Figure 4. Appearance of benign schwannoma demonstrating an Antoni A area (H&E x 400). The densely packed bipolar cells are characteristic of schwannoma.
Giant Sacral Schwannoma
Surg Neurol 1994;41:411-3
413
complete surgical removal possible. Total extirpation of the tumor is curative. In those patients where total
removal could not be accomplished, about half experienced recurrent disease [1].
References
2. De La Monte SM, Dorfman HD, Chandra R, Malawer M. Intraosseous schwannoma: histologic features, ultrastructure and review of the literature. Hum Pathol 1984;6:551-8.
1. Abernathy CD, Onofrio BM, Scheithauer B, Pairolero PC, Shires TC. Surgical management of giant sacral schwannomas. J Neurosurg 1986;65:286-95.
Giant Intrasacral Schwannoma: An Unusual Cause of Lumbrosacral Radiculopathy Jackson B. Salvant, Jr., M.D., and Harold F. Young, M.D. Medical College of Virginia, Richmond
Tumors involving the sacral spine are uncommon. These lesions should be considered in the differential diagnosis of lumbrosacral radiculopathy. Tumors in the sacrum can grow large while producing minimal symptoms. A recent case of sacral schwannoma (SS) treated at our institution is presented.
prick hypesthesia was noted over the left heel and the left Achilles's tendon reflex was diminished. Plain radiographs of the spine revealed a large lucent area in the left sacral ala that extended to the sacro-iliac joint (Figure 1). Magnetic resonance imaging (MRI) of the lumbar spine and sacrum confirmed a large homogeneous tumor within the sacrum, displacing the caudal theca and nerve roots (Figures 2 and 3). The patient underwent surgery via posterior sacral laminectomy and a large tumor attached to the left first sacral root was entirely removed. This required decompression of the sacral spinal canal and removal of additional bone over the lateral extent of the tumor. After identifying the caudal thecal sac, nerve roots were followed distally and carefully separated from the mass by microdissection. The dura was opened and internal decompression of the mass allowed for separation of the tumor. Pathologic examination revealed benign schwannoma (Figure 4). At 18 months follow-up, the patient is fully ambulatory and continent with no residual weakness. Mild pinprick hypesthesia in the first sacral dermatome persists.
Case R e p o r t
Discussion
A 32-year-old man noticed gradual low back pain extending into the left leg 2 weeks after lifting a heavy object. The pain was moderately severe and nearly constant, occasionally sharp in nature. Pain was present down the posterior aspect of the thigh and lower leg. Postural changes or Valsalva did not influence the extent or character of his pain. There were no complaints of weakness, bowel or urinary incontinence, or constipation. No changes in sensation were noted by the patient. Prior medical history was unremarkable. Examination of the spine was normal. Straight leg raising was normal. Motor strength was normal. Pin-
Less than 1% of all spinal schwannomas occur in the sacrum [1]. The differential diagnosis of these lesions is extensive, and radiography may not provide sufficient information for diagnosis in some cases. There are 23 previously reported cases of sacral schwannoma--the largest single series, which included 13 cases, is from the Mayo clinic [1]. To these we add our case. Most patients experience sciatica (79%), back pain (58%), or reflex changes (50%). Some patients experienced longstanding symptoms ranging up to 23 years. At diagnosis, patients ranged from 12 to 57 years of age, mean 35.2; 54% were male and 46% female. No patients had neurofibromatosis.
Address reprint requests to: Jackson B. Salvant, Jr., M.D., Division of Neurosurgery, Box 631, MCV Station, Richmond, VA 23298. Received August 9, 1993; accepted September 22, 1993.
Radiographic Evaluation
Salvant Jr JB, Young HF. Giant intrasacral schwannoma: an unusual cause of lumbosacral radiculopathy. Surg Neurol 1994;41:411-2.
Sacral schwannoma is a rare lesion (23 reported cases) with a tendency to reach large proportions. Symptoms are back and leg pain, leg weakness, hypoesthesias, paresthesias, constipation, and incontinence. The peak incidence is between ages 30 and 50. Radiographs of the sacrum are abnormal in nearly all cases. Computed tomography and magnetic resonance imaging may reveal large lesions with bony erosion and involvement of the soft tissues. The treatment of this lesion is complete removal, which is curative. KEYWORDS" Sacrum; Schwannoma; Sciatica; Tumor
© 1994 by ElsevierScienceInc.
Radiographic studies are vital to evaluation of these patients and a variety of examinations may be necessary o090-%019/94/$7.00
412
Surg Neurol 1994;41:411-3
Figure 1. Plain Radiograph. Lucency within the sacrum (arrows) can be
Salvant and Young
Figure 3. This axial M R image demonstrates the large tumor involving most of the left sacrum (small arrows). The right side of the sacrum (arrowhead) is preserved.
seen.
to adequately define the extent of the tumor. Plain radiographs demonstrated a lesion in 21 reported cases and were the sole preoperative study in three cases prior to the availability of computed tomography (CT). CT and MRI provide information regarding involvement of the spine, nerve roots, and retroperitoneum and may
exclude some processes in the differential diagnosis. Additional studies including myelography, barium enema, and intravenous urogram may also be indicated.
Pathologic Characteristics Pathologic features of these lesions are well-known and have been extensively described [2]. These lesions can involve retroperitoneal vascular structures and hollow organs. Grossly, the tumors are found to be firm and well-encapsulated and may be easily separated from adjacent bony structures. This characteristic often makes
........
.~
.
~ .
Figure 2. The extent of sacral involvement and displacement of the thecal sac can be seen in this T2-weighted sagital M R image demonstrating the mass filling the spinal canal and extending into the sacrum with a clear demarcation between tumor and bone.
Figure 4. Appearance of benign schwannoma demonstrating an Antoni A area (H&E x 400). The densely packed bipolar cells are characteristic of schwannoma.
Giant Sacral Schwannoma
Surg Neurol 1994;41:411-3
413
complete surgical removal possible. Total extirpation of the tumor is curative. In those patients where total
removal could not be accomplished, about half experienced recurrent disease [1].
References
2. De La Monte SM, Dorfman HD, Chandra R, Malawer M. Intraosseous schwannoma: histologic features, ultrastructure and review of the literature. Hum Pathol 1984;6:551-8.
1. Abernathy CD, Onofrio BM, Scheithauer B, Pairolero PC, Shires TC. Surgical management of giant sacral schwannomas. J Neurosurg 1986;65:286-95.