AUTHOR(S): Sieb, Jörn P., M.D.; Schultheiss, Rolf, M.D.
Neurosurgery 31; 1122-1125, 1992 ABSTRACT: A CASE OF rare segmental neurofibromatosis is presented. Multiple neurofibromas along the right sciatic nerve were found. Other typical manifestations of neurofibromatosis were absent. By microsurgical dissection, it was possible to remove the neurofibromas from the nerve trunks and to preserve all motor and sensory functions. Classification of the different neurofibromatosis types is briefly reviewed. The problems of resection of benign major nerve trunk tumors in neurofibromatosis are discussed. KEY WORDS: Neurofibroma; NF-5; Peripheral nerve tumors; Schwannoma; Von Recklinghausen disease Segmental neurofibromatosis is rare among the different types of neurofibromatosis. In 1989, Kaplan and Pestena (4) found only 19 cases published in English medical literature. In this type of neurofibromatosis, the typical signs of neurofibromatosis, such as café au lait spots and neurofibromas, are localized to one side of the body. We report a case of segmental neurofibromatosis with multiple neurofibromas occurring exclusively along the right sciatic nerve. There were no other manifestations of neurofibromatosis. CASE REPORT A 36-year-old woman sought treatment at our hospital complaining of right leg pain. Since the age of 16 years, she had suffered from increasing continuous pain in the anterior and medial part of the right thigh. In the following years, the cause of this pain remained elusive. A radicular syndrome caused by a disc prolapse was suspected but could not be confirmed radiologically. Later, the medial meniscus was resected from her right knee without any benefit. No other cases of neurofibromatosis are known in her family. Four siblings are healthy. Her two sons and a daughter, ages 19, 9, and 13 years, respectively, show no signs of neurofibromatosis. At examination, she appeared intellectually normal. The right-ankle jerk reflex was decreased. There was slight weakness of the right quadriceps and biceps femoris. No significant difference in leg circumference was found. There were no sensory abnormalities. Movement at her right knee joint was restricted. Flexion of her right knee induced shooting pain down her lower leg. Three subcutaneous nodules
DISCUSSION Neurofibromatosis is the generic term for a group of independent genetic diseases with different clinical pictures and diagnostic criteria. These differ phenotypically and have different courses, complications, and patterns of inheritance. Therefore, accurate diagnosis is of practical importance for the care of patients with neurofibromatosis and their next of kin. NF-1, the most frequent type of neurofibromatosis, corresponds to the disease described by von Recklinghausen in 1882. Among other criteria, NF-1 is characterized by the presence of at least two neurofibromas and six or more café au lait spots. In adults, examination of the iris almost always shows Lisch nodules. The hallmark of NF-2 is the presence of bilateral acoustic neurinomas. Other cranial nerve
Downloaded from https://academic.oup.com/neurosurgery/article-abstract/31/6/1122/2752150 by East Carolina University user on 14 January 2019
Departments of Neurology (JPS) and Neurosurgery (RS), University Hospital, Bonn, Germany
were palpable behind her right knee. There were no other skin changes, including café au lait spots or freckling. Slit-lamp examination revealed no posterior subcapsular cataracts or Lisch iris nodules. Computed tomographic scans showed marked tumorous enlargement of the sciatic nerve throughout the right thigh (Fig. 1). At surgery, there were tumor cords along the peroneal and tibial nerves from the foramen infrapyriform to just beyond the right knee (Fig. 2). Numerous tumor nodules surrounded by a mucous sub-stance were found along these two trunks, forming a solid tumor string. Other solitary tumors surrounded the two nerve trunks in the corpus adiposum of the right knee. The corpus adiposum was resected. The popliteal vessels were surrounded and constricted by smaller tumors and had to be freed. Macroscopically visible tumors were extirpated by using a microsurgical technique with longitudinal incision of the epineurium. However, some central bead-like tumors (maximum diameter, 2 mm) along the distal fascicles of the tibial nerve were not removed to avoid undue risk to the function of the affected nerve. The histological examination showed neurofibromas with thin fibrous capsules. Postoperatively, there were no new neurological deficits. The patient's leg pain was markedly reduced, and she was no longer limited in her daily activities. However, contact with a small zone behind her right knee produced a dysesthetic sensation; manual pressure at this site elicited an uncomfortable sensation that radiated to the inguinal region. Eighteen months later, magnetic resonance imaging (MRI) scans showed two tumors in the right adductor canal and in the ventrolateral part of the thigh (Fig. 3). A second operation was performed. The tumors originated from small branches of the right sciatic nerve. The saphenous nerve was unaffected. Macroscopic and histological findings were similar to those of the previously resected tumors. Three years after the last operation, an MRI examination of the brain revealed no abnormalities. MRI scans of the leg with gadolinium enhancement showed no tumor growth. A clinical examination did not reveal any change.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Neurosurgery 1992-98 December 1992, Volume 31, Number 6 1122 Segmental Neurofibromatosis of the Sciatic Nerve: Case Report Case Report
Establishing such a dissection plane allows complete excision of the tumor, with preservation of nerve function. If a plane of dissection cannot be achieved, it is reasonable to perform a biopsy of the lesions to rule out malignant changes and to terminate the operation at that time. Finally, we would like to emphasize the potential for major neurological deficits whenever a benign neurofibroma or schwannoma is excised from a nerve trunk. Further severe dysesthesia or other painful sequelae can occur after resection of peripheral nerve tumors. However, the chances of serious complications can be minimized by using careful microsurgical techniques. Received, January 17, 1992. Accepted, July 7, 1992. Reprint requests: J. P. Sieb, M. D., Neuromuscular Research Laboratory, Guggenheim Bldg. 8, Mayo Clinic, Rochester, MN 55905.
1. 2.
3.
4. 5.
6.
7.
8.
9.
10. 11.
Ariel IM: Tumors of the peripheral nervous system. CA 33:282-299, 1983. Boltshauser E, Stocker H, Mächler M: Neurofibromatosis type 1 in a child of a parent with segmental neurofibromatosis (NF5) Neurofibromatosis 2:244-245, 1989. Heimann R, Verhest A, Verschraegen J, Grosjean W, Draps J, Hecht F: Hereditary intestinal neurofibromatosis. Neurofibromatosis 1:26-32, 1988. Kaplan DL, Pestena A: Cutaneous segmental neurofibromatosis. I. A distinctive genetic disease. South Med J 82:516-517, 1989. Menon AG, Gusella JF, Seizinger BR: Progress toward the isolation and characterization of the genes causing neurofibromatosis. Brain Pathol 1:33-40, 1990. National Institutes of Health Consensus Development Conference: Neurofibromatosis. Conference statement. Arch Neurol 45:575578, 1988. Pickard LR, Rose JE: Avoidable complications of resection of major nerve trunk neurofibromas and schwannomas. Neurofibromatosis 1:43-49, 1988. Pulst S-M, Riccardi VM, Fain P, Korenberg JR: Familial spinal neurofibromatosis: Clinical and DNA linkage analysis. Neurology 41:1923-1927, 1991. Riccardi VM: Neurofibromatosis. Phenotype, Natural History and Pathogenesis. The Johns Hopkins University Press, Baltimore, 1992, ed 2, pp 224-250. Riccardi VM: Neurofibromatosis: Clinical heterogeneity. Curr Probl Cancer 7:1-34, 1982. Rubenstein AE, Bader JL, Aron AA, Wallace S: Familial transmission of segmental neurofibromatosis. Neurology 33 [Suppl 2]:76, 1983 (abstr).
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
REFERENCES: (1-14)
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and central nervous system tumors may occur. Lisch nodules are absent. Patients with NF-2 may or may not have café au lait spots or cutaneous tumors. A National Institutes of Health Consensus Development Conference defined the diagnostic criteria for both types in 1988 (6). It is also possible to distinguish these two types by using molecular techniques. The NF-1 mutation is located on Chromosome 17 and that of NF-2 on Chromosome 22 (5). In 1982, Riccardi (9,10) proposed distinguishing eight different types of neurofibromatosis, including NF-1, NF-2, and segmental neurofibromatosis. However, this classification is not generally accepted. At the present time, only the mutations of NF-1 and NF-2 are known. Additional unusual variants of neurofibromatosis, such as intestinal and a spinal form, have been reported (3,8). Recently, we described a family with inherited meningiomas and ependymomas. Signs typical of NF-1 and NF-2 were absent (12). Linkage analysis with DNA markers tightly linked to the NF-1 and NF-2 genes probably excluded a mutation of both loci in this family. Our case should be classified as segmental neurofibromatosis or NF-5, according to the classification by Riccardi (9,14). The manifestations of neurofibromatosis were restricted to one limited area of the body, with no crossing of the midline. Subcutaneous neurofibromas were only evident at the right knee. There were no café au lait spots or freckling. Slit-lamp examination did not reveal iris Lisch nodules. Our case is sporadic, as have been most reported cases of segmental neurofibromatosis (13). The cause is suspected to be a postzygotic mutation of the NF-1 gene in a primitive cell of the neural crest. However, Rubenstein et al. (11) reported one family with two cases of NF-5; and NF-1 occurred in a child of a parent with segmental neurofibromatosis (2). Thus, the mode of inheritance of this neurofibromatosis type is uncertain. In the foreseeable future, it should be possible to differentiate between segmental and generalized neurofibromatosis by using DNA analysis. Serious complications of neurofibromatosis, such as neurofibrosarcoma, have not been reported in segmental neurofibromatosis. The classic description of neurofibromas would imply that because of the diffuse nature of the tumor, complete excision from a major nerve trunk would result in complete loss of distal nerve function (1,7). By comparison, complete excision of a schwannoma from a peripheral nerve trunk can be performed without damage because the lesions usually arise from only one fiber, with displacement of the other nerve fibers. Unfortunately, intraoperative distinction between neurofibromas and schwannomas is not possible in all cases, and a histological examination is usually required. Our case illustrates another possible anatomic pattern of neurofibromas involving large nerve trunks. The tumor may involve only a part of the nerve, with displacement of remaining fascicles. According to Pickard and Rose (7), the epineurium of benign peripheral nerve tumors should be incised longitudinally by using microscopic techniques.
13.
14.
COMMENTS This report by Sieb and Schultheiss points out several important features of surgery of tumors of major peripheral nerves in patients with neurofibromatosis: 1. The era of "exploratory" surgery is past. Magnetic resonance imaging nicely documents the extent of tumor involvement and markedly helps in surgical planning. 2. Although some nerve tumors in NF-1 are plexiform neurofibromas that encase important axons and cannot be resected without substantial neural morbidity, others may involve only a few fascicles or may be schwannomas, allowing for complete removal with little or no deficit. Presently, no radiology test allows this distinction preoperatively; this must be made at the time of surgery. Furthermore, in my experience, patients with NF-2 almost always have schwannomas that are more easily removed, compared with some patients with NF-1. As yet, not enough segmental cases have been seen by me, or by others, to allow for categorical comment. Therefore, this case re-port is an important contribution in that area. 3. With regard to pain, it should be noted that this patient had useful pain relief with tumor removal, a feature that I, too, have seen. However, caution must be exercised, because severe dysesthetic pain can also be produced by surgery in some cases. It is important for the surgeon to remember that neurofibromatosis cannot be cured by surgery. The patient's symptoms and the goals of the surgery must always be kept in mind. In some cases, especially where tumors are small, asymptomatic, and not growing, often the best surgery is no surgery. Robert L. Martuza Washington, District of Columbia The authors present an interesting example of regionalized neurofibromatosis. This disorder is characterized by multiple tumors affecting one limb or region of anatomy without tumors occurring elsewhere in the body or the usual systemic stigmata of von Recklinghausen's disease (VRD). Unfortunately, regionalized VRD is often expressed somewhat differently than in the author's case. More often, multiple tumors are intrinsic to multiple nerves, or, if related to one nerve as it was in this case, they are not only intrinsic but up and down at
Downloaded from https://academic.oup.com/neurosurgery/article-abstract/31/6/1122/2752150 by East Carolina University user on 14 January 2019
Sieb JP, Pulst S-M, Buch A: Familial CNS tumors. J Neurol 239:343-344, 1992. Sloan JB, Fretzin DF, Bovenmyer DA: Genetic counseling in segmental neurofibromatosis. J Am Acad Dermatol 22:461-467, 1990. Theiler R, Stocker H, Boltshauser E: Zur Klassifizierung atypischer NeurofibromatoseFormen. Schweiz Med Wochenschr 121:446455, 1991.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
12.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Figure 2. Right dorsal thigh before (left) and after (right) extirpation of the neurofibromas. Preoperatively, the peroneal and tibial nerves were enclosed by multiple tumors. The tumors extend to the gluteus maximus muscle proximally. After extirpation, the nerves and the popliteal artery and vein are clearly recognizable.
Downloaded from https://academic.oup.com/neurosurgery/article-abstract/31/6/1122/2752150 by East Carolina University user on 14 January 2019
Figure 1. Computed tomography of both thighs shows several large tumor nodules along the right sciatic nerve (arrows). These tumors were removed at the first operation (see Fig. 2).
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
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Figure 3. Eighteen months after the first operation, an MRI scan shows increased T2-weighted signal images next to the right femur in the adductor canal, corresponding to two neurofibromas (arrows). These neurofibromas originated from small branches of the sciatic nerve.
Neurosurgery 31; 1122-1125, 1992 ABSTRACT: A CASE OF rare segmental neurofibromatosis is presented. Multiple neurofibromas along the right sciatic nerve were found. Other typical manifestations of neurofibromatosis were absent. By microsurgical dissection, it was possible to remove the neurofibromas from the nerve trunks and to preserve all motor and sensory functions. Classification of the different neurofibromatosis types is briefly reviewed. The problems of resection of benign major nerve trunk tumors in neurofibromatosis are discussed. KEY WORDS: Neurofibroma; NF-5; Peripheral nerve tumors; Schwannoma; Von Recklinghausen disease Segmental neurofibromatosis is rare among the different types of neurofibromatosis. In 1989, Kaplan and Pestena (4) found only 19 cases published in English medical literature. In this type of neurofibromatosis, the typical signs of neurofibromatosis, such as café au lait spots and neurofibromas, are localized to one side of the body. We report a case of segmental neurofibromatosis with multiple neurofibromas occurring exclusively along the right sciatic nerve. There were no other manifestations of neurofibromatosis. CASE REPORT A 36-year-old woman sought treatment at our hospital complaining of right leg pain. Since the age of 16 years, she had suffered from increasing continuous pain in the anterior and medial part of the right thigh. In the following years, the cause of this pain remained elusive. A radicular syndrome caused by a disc prolapse was suspected but could not be confirmed radiologically. Later, the medial meniscus was resected from her right knee without any benefit. No other cases of neurofibromatosis are known in her family. Four siblings are healthy. Her two sons and a daughter, ages 19, 9, and 13 years, respectively, show no signs of neurofibromatosis. At examination, she appeared intellectually normal. The right-ankle jerk reflex was decreased. There was slight weakness of the right quadriceps and biceps femoris. No significant difference in leg circumference was found. There were no sensory abnormalities. Movement at her right knee joint was restricted. Flexion of her right knee induced shooting pain down her lower leg. Three subcutaneous nodules
DISCUSSION Neurofibromatosis is the generic term for a group of independent genetic diseases with different clinical pictures and diagnostic criteria. These differ phenotypically and have different courses, complications, and patterns of inheritance. Therefore, accurate diagnosis is of practical importance for the care of patients with neurofibromatosis and their next of kin. NF-1, the most frequent type of neurofibromatosis, corresponds to the disease described by von Recklinghausen in 1882. Among other criteria, NF-1 is characterized by the presence of at least two neurofibromas and six or more café au lait spots. In adults, examination of the iris almost always shows Lisch nodules. The hallmark of NF-2 is the presence of bilateral acoustic neurinomas. Other cranial nerve
Downloaded from https://academic.oup.com/neurosurgery/article-abstract/31/6/1122/2752150 by East Carolina University user on 14 January 2019
Departments of Neurology (JPS) and Neurosurgery (RS), University Hospital, Bonn, Germany
were palpable behind her right knee. There were no other skin changes, including café au lait spots or freckling. Slit-lamp examination revealed no posterior subcapsular cataracts or Lisch iris nodules. Computed tomographic scans showed marked tumorous enlargement of the sciatic nerve throughout the right thigh (Fig. 1). At surgery, there were tumor cords along the peroneal and tibial nerves from the foramen infrapyriform to just beyond the right knee (Fig. 2). Numerous tumor nodules surrounded by a mucous sub-stance were found along these two trunks, forming a solid tumor string. Other solitary tumors surrounded the two nerve trunks in the corpus adiposum of the right knee. The corpus adiposum was resected. The popliteal vessels were surrounded and constricted by smaller tumors and had to be freed. Macroscopically visible tumors were extirpated by using a microsurgical technique with longitudinal incision of the epineurium. However, some central bead-like tumors (maximum diameter, 2 mm) along the distal fascicles of the tibial nerve were not removed to avoid undue risk to the function of the affected nerve. The histological examination showed neurofibromas with thin fibrous capsules. Postoperatively, there were no new neurological deficits. The patient's leg pain was markedly reduced, and she was no longer limited in her daily activities. However, contact with a small zone behind her right knee produced a dysesthetic sensation; manual pressure at this site elicited an uncomfortable sensation that radiated to the inguinal region. Eighteen months later, magnetic resonance imaging (MRI) scans showed two tumors in the right adductor canal and in the ventrolateral part of the thigh (Fig. 3). A second operation was performed. The tumors originated from small branches of the right sciatic nerve. The saphenous nerve was unaffected. Macroscopic and histological findings were similar to those of the previously resected tumors. Three years after the last operation, an MRI examination of the brain revealed no abnormalities. MRI scans of the leg with gadolinium enhancement showed no tumor growth. A clinical examination did not reveal any change.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Neurosurgery 1992-98 December 1992, Volume 31, Number 6 1122 Segmental Neurofibromatosis of the Sciatic Nerve: Case Report Case Report
Establishing such a dissection plane allows complete excision of the tumor, with preservation of nerve function. If a plane of dissection cannot be achieved, it is reasonable to perform a biopsy of the lesions to rule out malignant changes and to terminate the operation at that time. Finally, we would like to emphasize the potential for major neurological deficits whenever a benign neurofibroma or schwannoma is excised from a nerve trunk. Further severe dysesthesia or other painful sequelae can occur after resection of peripheral nerve tumors. However, the chances of serious complications can be minimized by using careful microsurgical techniques. Received, January 17, 1992. Accepted, July 7, 1992. Reprint requests: J. P. Sieb, M. D., Neuromuscular Research Laboratory, Guggenheim Bldg. 8, Mayo Clinic, Rochester, MN 55905.
1. 2.
3.
4. 5.
6.
7.
8.
9.
10. 11.
Ariel IM: Tumors of the peripheral nervous system. CA 33:282-299, 1983. Boltshauser E, Stocker H, Mächler M: Neurofibromatosis type 1 in a child of a parent with segmental neurofibromatosis (NF5) Neurofibromatosis 2:244-245, 1989. Heimann R, Verhest A, Verschraegen J, Grosjean W, Draps J, Hecht F: Hereditary intestinal neurofibromatosis. Neurofibromatosis 1:26-32, 1988. Kaplan DL, Pestena A: Cutaneous segmental neurofibromatosis. I. A distinctive genetic disease. South Med J 82:516-517, 1989. Menon AG, Gusella JF, Seizinger BR: Progress toward the isolation and characterization of the genes causing neurofibromatosis. Brain Pathol 1:33-40, 1990. National Institutes of Health Consensus Development Conference: Neurofibromatosis. Conference statement. Arch Neurol 45:575578, 1988. Pickard LR, Rose JE: Avoidable complications of resection of major nerve trunk neurofibromas and schwannomas. Neurofibromatosis 1:43-49, 1988. Pulst S-M, Riccardi VM, Fain P, Korenberg JR: Familial spinal neurofibromatosis: Clinical and DNA linkage analysis. Neurology 41:1923-1927, 1991. Riccardi VM: Neurofibromatosis. Phenotype, Natural History and Pathogenesis. The Johns Hopkins University Press, Baltimore, 1992, ed 2, pp 224-250. Riccardi VM: Neurofibromatosis: Clinical heterogeneity. Curr Probl Cancer 7:1-34, 1982. Rubenstein AE, Bader JL, Aron AA, Wallace S: Familial transmission of segmental neurofibromatosis. Neurology 33 [Suppl 2]:76, 1983 (abstr).
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
REFERENCES: (1-14)
Downloaded from https://academic.oup.com/neurosurgery/article-abstract/31/6/1122/2752150 by East Carolina University user on 14 January 2019
and central nervous system tumors may occur. Lisch nodules are absent. Patients with NF-2 may or may not have café au lait spots or cutaneous tumors. A National Institutes of Health Consensus Development Conference defined the diagnostic criteria for both types in 1988 (6). It is also possible to distinguish these two types by using molecular techniques. The NF-1 mutation is located on Chromosome 17 and that of NF-2 on Chromosome 22 (5). In 1982, Riccardi (9,10) proposed distinguishing eight different types of neurofibromatosis, including NF-1, NF-2, and segmental neurofibromatosis. However, this classification is not generally accepted. At the present time, only the mutations of NF-1 and NF-2 are known. Additional unusual variants of neurofibromatosis, such as intestinal and a spinal form, have been reported (3,8). Recently, we described a family with inherited meningiomas and ependymomas. Signs typical of NF-1 and NF-2 were absent (12). Linkage analysis with DNA markers tightly linked to the NF-1 and NF-2 genes probably excluded a mutation of both loci in this family. Our case should be classified as segmental neurofibromatosis or NF-5, according to the classification by Riccardi (9,14). The manifestations of neurofibromatosis were restricted to one limited area of the body, with no crossing of the midline. Subcutaneous neurofibromas were only evident at the right knee. There were no café au lait spots or freckling. Slit-lamp examination did not reveal iris Lisch nodules. Our case is sporadic, as have been most reported cases of segmental neurofibromatosis (13). The cause is suspected to be a postzygotic mutation of the NF-1 gene in a primitive cell of the neural crest. However, Rubenstein et al. (11) reported one family with two cases of NF-5; and NF-1 occurred in a child of a parent with segmental neurofibromatosis (2). Thus, the mode of inheritance of this neurofibromatosis type is uncertain. In the foreseeable future, it should be possible to differentiate between segmental and generalized neurofibromatosis by using DNA analysis. Serious complications of neurofibromatosis, such as neurofibrosarcoma, have not been reported in segmental neurofibromatosis. The classic description of neurofibromas would imply that because of the diffuse nature of the tumor, complete excision from a major nerve trunk would result in complete loss of distal nerve function (1,7). By comparison, complete excision of a schwannoma from a peripheral nerve trunk can be performed without damage because the lesions usually arise from only one fiber, with displacement of the other nerve fibers. Unfortunately, intraoperative distinction between neurofibromas and schwannomas is not possible in all cases, and a histological examination is usually required. Our case illustrates another possible anatomic pattern of neurofibromas involving large nerve trunks. The tumor may involve only a part of the nerve, with displacement of remaining fascicles. According to Pickard and Rose (7), the epineurium of benign peripheral nerve tumors should be incised longitudinally by using microscopic techniques.
13.
14.
COMMENTS This report by Sieb and Schultheiss points out several important features of surgery of tumors of major peripheral nerves in patients with neurofibromatosis: 1. The era of "exploratory" surgery is past. Magnetic resonance imaging nicely documents the extent of tumor involvement and markedly helps in surgical planning. 2. Although some nerve tumors in NF-1 are plexiform neurofibromas that encase important axons and cannot be resected without substantial neural morbidity, others may involve only a few fascicles or may be schwannomas, allowing for complete removal with little or no deficit. Presently, no radiology test allows this distinction preoperatively; this must be made at the time of surgery. Furthermore, in my experience, patients with NF-2 almost always have schwannomas that are more easily removed, compared with some patients with NF-1. As yet, not enough segmental cases have been seen by me, or by others, to allow for categorical comment. Therefore, this case re-port is an important contribution in that area. 3. With regard to pain, it should be noted that this patient had useful pain relief with tumor removal, a feature that I, too, have seen. However, caution must be exercised, because severe dysesthetic pain can also be produced by surgery in some cases. It is important for the surgeon to remember that neurofibromatosis cannot be cured by surgery. The patient's symptoms and the goals of the surgery must always be kept in mind. In some cases, especially where tumors are small, asymptomatic, and not growing, often the best surgery is no surgery. Robert L. Martuza Washington, District of Columbia The authors present an interesting example of regionalized neurofibromatosis. This disorder is characterized by multiple tumors affecting one limb or region of anatomy without tumors occurring elsewhere in the body or the usual systemic stigmata of von Recklinghausen's disease (VRD). Unfortunately, regionalized VRD is often expressed somewhat differently than in the author's case. More often, multiple tumors are intrinsic to multiple nerves, or, if related to one nerve as it was in this case, they are not only intrinsic but up and down at
Downloaded from https://academic.oup.com/neurosurgery/article-abstract/31/6/1122/2752150 by East Carolina University user on 14 January 2019
Sieb JP, Pulst S-M, Buch A: Familial CNS tumors. J Neurol 239:343-344, 1992. Sloan JB, Fretzin DF, Bovenmyer DA: Genetic counseling in segmental neurofibromatosis. J Am Acad Dermatol 22:461-467, 1990. Theiler R, Stocker H, Boltshauser E: Zur Klassifizierung atypischer NeurofibromatoseFormen. Schweiz Med Wochenschr 121:446455, 1991.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
12.
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
Figure 2. Right dorsal thigh before (left) and after (right) extirpation of the neurofibromas. Preoperatively, the peroneal and tibial nerves were enclosed by multiple tumors. The tumors extend to the gluteus maximus muscle proximally. After extirpation, the nerves and the popliteal artery and vein are clearly recognizable.
Downloaded from https://academic.oup.com/neurosurgery/article-abstract/31/6/1122/2752150 by East Carolina University user on 14 January 2019
Figure 1. Computed tomography of both thighs shows several large tumor nodules along the right sciatic nerve (arrows). These tumors were removed at the first operation (see Fig. 2).
Redistribution of this article permitted only in accordance with the publisher’s copyright provisions.
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Figure 3. Eighteen months after the first operation, an MRI scan shows increased T2-weighted signal images next to the right femur in the adductor canal, corresponding to two neurofibromas (arrows). These neurofibromas originated from small branches of the sciatic nerve.
