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Endometriosis of the sciatic nerve: case report demonstrating the value of MR imaging
European Journal of Obstetrics & Gynecology and ReproductiveBiology 58 (1995) W-202
ELSEVIER
Case report
Endometriosis of the sciatic nerve: case report demonstrating the value of MR imaging Ph. Descamps* ‘, J.P. Cottierb, I. Barre’, Ph. Rossetd, J. Laffontb, J. Lansaca, G. Bodya BDepartment of Obstetrics and Gynecology, University Hospital, 2 Bvd. Totmel& 37044 Tours, France bDepartment of h’euroradiology, University Hospital, 2 Bvd. Tonaelik, 37044 Tours, France ‘Department of Pathology, University Hospital, 2 Bvd. Tonnelk 37044 Tours, France dDepartment of Orthopedics, University Hospital, 2 Bvd. TonneIlk, 37044 Tours, France
Accepted7 August1994
Among the many causes of sciatica, endome~osis, a rare aetiology, should be considered in ~enst~ting women in view of the diagnostic strategy and ensuing therapeutic implications. We report a case of sciatic nerve involvement with endometriosis in contact with the nerve in the left sciatic notch. Exploration by MRI was invaluable for the diagnosis, revealing a signal on the stem of the nerve suggestive of a lesion with haemorrhagic content. Keywurdr: Endometriosis; Sciatica; MRI
1. Introduction
Endome~osis is a rare cause of sciatica. Since the tirst case of endometriosis-induced sciatica reported by Schlicke in 1946 [ 11, 18 histologically proven observations have been reported. For four of them [2-51 computed tomography (CT) of the pelvis revealed a lesion on the sciatic nerve. None of these patients underwent magnetic resonance imaging (MRI). We report a case of sciatic nerve involvement explored by MRI, with endometriosis in contact with the nerve in the left sciatic notch. 2. case report A 39-year-old woman {gravida 1, para 1) was referred for episodic pain in her back and left leg associated with difficulties in walking, of slow progressive onset. Clinical history revealed cyclic left sciatica which had evolved * Corresponding author.
over 3 years. Pain began on the first day of menstruation and continued for the 5 or 6 days of menstruation. It was poorly controlled by non-steroid anti-inhalator drugs. The pain recurred during the following cycle after a pain-free period. CT scan of the lumbar vertebrae 6 months before had shown only a slightly bulging L-5-S 1 disc. On examination, she walked with left steppage gait. There was paralysis of the anterior tibia1 and peroneal muscles of the left ieg associated with hypoesthesia in the L-5 area. Left straight leg-raising did not produce discomfort (no Lasegue’s sign). Achilles reflex of the left contirmed foot was not present. Electromyogram damage to the peroneal nerve with slight damage to the tibia1 nerve. Truncal sciatica was suspected and pelvic MRI revealed a distinct mass of approximately 2 cm in diameter in the left sciatic notch (Fig. 1). The lesion appeared to be situated in the lower part of the piriform muscle, in contact with the sciatic nerve in the gluteal area. The lesion was hy~~nten~ on the Tl and T2 weighted images, partially surrounded by a
0 1995 Elsevier Science Ireland Ltd. All rights reserved 0028.2243/95/$09.50 SSDI 0028-2243(94)01946-5
200
Ph. Descamps et al. /European Journal Obstetrics & Gynecology and Reproduction Biology 58 (1995) 199-202
Fig. 1. Post-gadolinium coronal Tl-weighted image showing the lesion close to the sciatic nerve (arrowhead).
thin hypointense zone in both ponderations. The lesion was not enhanced by gadolinium injection. Surgery revealed a purplish mass situated within the piriform muscle, developing below and outside in contact with the sciatic nerve. The whole region was inflamed. Section of the tumour released a chocolate coloured fluid. Preliminary examination indicated the diagnosis of endometriosis. The cyst was excised and neurolysis of the sciatic nerve was performed. A pathological examination (Fig. 1) revealed areas of typical endometrial glands s~round~ by stroma and bordered by vessels with occasional foci of hemosiderin-laden macrophages typical of endometriosis. Ultrasonography and laparascopy revealed no other pelvic localisations. Treatment with Cn-RH agonist (Triptorelin, 3.75 m~month) was prescribed for 3 months followed by Promegeston (0.5 mg). All pain had disappeared on completion of treatment. Electromyelogram performed 5 months after surgery revealed initial neurologic recovery. 3. Discussion Endometriosis is defined by the presence of ectopic
islets of endometrial tissue. It is a very common gynaecologycal disease affecting between 1% and 5% of women of reproductive age [6] but its true frequency is difficult to estimate because in many cases there is no parallel between anatomical lesions and clinical features. The localisation of endometrial nodes at the root of a nerve or in the nerve stem is one of the rarest topographical variations of this condition. The precise pathogenesis of endometrial sciatica is still unknown. The existence of a peritoneal diverticulum permitting endomet~al tissue to migrate to the sciatic nerve from the site of genital endometriosis or after tube reflux has been suggested [7], but this ‘pocket’ sign is rarely observed during pelvic examination. Haematogenic migration after vascular damage such as a slight injury or surgery could also be the cause, especially in patients without other sites of endometriosis. As endometriosis is hormone dependent, the haemorrhage penetrates neighbouring tissues during each menstrual cycle and triggers a considerable in~a~atory reaction. All the published cases give the same descriptions of pain [2,8]. The sciatica is first cyclical and occurs during menstrual periods. It sometimes begins l-2
ph. Descamps ef al. /European Jomai
Obstetrics & Gynecology and Reproduction Biology S8 (1995) 199-202
days before or after the first day of a period. The pain is intense and progressive, with a pain-free interval which gradually shortens until, after a few years, it becomes permanent. Although, in one case 191 pain disappeared during pre~an~y (which is classic of all endometriosis symptoms), in all other published cases it had no effect on the sciatic pain [2]. There is a clear predominance of sciatic pain on the right side [S]. It has been suggested that the sigmoid impedes the implantation of endometriosis nodes on the left sciatic nerve. Sensorimotor deficit can appear. Such progressive sensory motor deficit is sometimes the only manifestation of sciatic nerve involvement. Straight leg-raising producing discomfort (Lasegue’s sign) is often present and tenderness in the sciatic notch is often elicited. There may be weakness and atrophy of muscles innervated by the sciatic nerve, and appropriate sensory loss [2]. Pelvic exa~nation is usually normal, but foci of endometriosis may be seen or palpated (in one case, palpation of the utero-sacral ligament produced sciatic neuralgia) [9]. Elec~omyogram can identify peripheral neuro~enous syndrome by showing signs of denervation as well as slowing of conduction speed. Moreover, it makes possible the distinction between root and stem damage and the surveillance of treatment after evolution. In different pelvic localisations, endometriosis presents different aspects on CT scan: cystic, solid or mixed. There have been some reports of CT scans of endometriosis-induced sciatica [2-51 but, to our knowledge, none of MRI exploration of catameniai sciatica. The sensitivity and specificity of this technique in the diagnosis of endometriosis in usual pelvic localizations (ovaries and uterus) is estimated to be around 700/o [ 10,l I]. These cystic lesions are typically surrounded by an hypointense rim on Tl and T2 weighted images related to their fibrous capsule (121. Classically, the interior of the cyst is hyperintense in Tl and T2 weighted images due to the presence of paramagnetic methemo~obin, There can be other types of signal: hypointensity in both sequences or hypointensity on Tl weighted images associated with hyperintensity on T2 weighted images [lO,ll]. The intensity of the signal is a function of the quantity and age of the hemorrhage on the one hand and of the pro~rtion of endomet~al cells and stroma on the other hand. In our case, the lesion presented h~rintensity on both ~nderal sequences related to its hematic content and a peripheral hypointensity which could have been linked to the presence of fibrous tissue and granular tissue composed of macrophages filled with hemosiderin. In view of the nerve symptomatology and the topography of the lesion, the principal differential diagnosis is benign neurogenic tumour. On MRI [ 131 neurinoma and neurofibroma are hypointense in the ponderal sequence in Tl and heterogeneously hyper-
201
intense in the ponderal sequence in T2 (with a central zone of low intensity for neuro~bromas). These trots are usually greatly enhanced after gadolinium injection. In the few observations of cystic forms of these tumours, the signal was never hy~~ntense in the ponderal sequence in Tl [14]. The ~tameni~ rhythm in our case of pain associated with the signal from the lesion (hyperintensity on Tl and T2 weighted images as in the signal from ovarian endometriosic cysts, absence of enhancement after gadolinium injection) should first suggest a diagnosis of endometriosis. Treatment is based on excision of the lesion in contact with the sciatic nerve (confirming the diagnosis and giving the best chance of neurological recovery) and associated treatment of the other localizations of endometriosis (laparoscopic surgery and/or medical treatment, particularly with GnRH agonists). Therefore, endometriosis may result in chronic sciatica which is catamenial and increases in intensity and duration during successive cycles to the point of ~coming reagent. MRI may support the diagnosis by revealing a signal on the stem of the nerve suggestive of a lesion with haemorrha~~ content.
We wish to express our gratitude to Professor D. Sirinelli for his help and to Mrs D. Raine for her ~ng~sh lecture. References Schlicke CP. Ectopic endometrial tissue in the thigh. J Am Med Assoc 1946; 132: 445. Saiazar-Grueso E, Roos R. Sciatic endometriosis: a treatable sensorimotor mononeuropathy. Neurology 1986; 36: 1360-1363. Hibbard J, Schreiber JR. Footdrop due to sciatic nerve endometriosis. Am J Obstet Gynecol 1984; 149: 800-801. Fishman EK, Scatarige JC, Satsouk FA, Rosenhein NB, Siegelman SS. Computed tomography of endometriosis. J Comput Assist Tomogr 1983; 7: 257-264. Richards BJ, Gillet WR, Polloc KM. Reversal of footdrop in sciatic nerve endometriosis. J Neurol Neurosurg Psychiatry 1991; 54: 935-940. Barbieri R.L. Endometriosis 1990. Current treatment approaches. Drugs 1990; 39: 502-510. Hedd HB, Welch JS, Mussey E et al. Cyclic sciatica: report of a case with introduction of a new surgical sign. J Am Med Assoc 1962; 180: 521. Torkelson SJ, Lee RA, Hildahl DE. Endrometriosis of the sciatic nerve: a report of two cases and a review of the litterature. Gbstet Gynecoi 1988; 71: 473-477. Dagnehe J. Lombo-sciatalgie et endocrinologie: contribution B t’&ude des endom~triomes h~t~rotopiques. Ann Endocrinoi 1947; 8: 26-31. Arrive L, Hricak H, Martin MC. Pelvic endometriosis: MR imaging. Radiology 1989; 171: 687-692. Zawin M, McCarthy S, Scoutt L, Comite F. Emodometriosis: appearance and detection et MR imaging. Radiology 1989; 171: 693-696.
202 [I21 Nishimura
Ph. Descomps et al. /European Journal Obstetrics & Gynecology and Reproduction Biology 58 (1995) 199-202
K, Togashi K, Itohk, Fujisawa I, Noma S, Kawamura Y et al. Endometrial Cysts of the ovary: MR imaging Radiology 1987; 162: 315-318. [13] Suh JS, Abenoxa P, Galloway HR, Everson LI, Grifiths HJ. Peripheral (extracranial) nerve tumors: correlation of MR imaging and histological findings. Radiology 1992; 183: 341-346.
[14] Cerofolini E, Landi A, DeSantis G, Maiorana A, Canossi G, Romagnoli R. MR of benign peripheral nerve sheath tumors. J Comput Assist Tomogr 1991; 15: 593-597.
ELSEVIER
Case report
Endometriosis of the sciatic nerve: case report demonstrating the value of MR imaging Ph. Descamps* ‘, J.P. Cottierb, I. Barre’, Ph. Rossetd, J. Laffontb, J. Lansaca, G. Bodya BDepartment of Obstetrics and Gynecology, University Hospital, 2 Bvd. Totmel& 37044 Tours, France bDepartment of h’euroradiology, University Hospital, 2 Bvd. Tonaelik, 37044 Tours, France ‘Department of Pathology, University Hospital, 2 Bvd. Tonnelk 37044 Tours, France dDepartment of Orthopedics, University Hospital, 2 Bvd. TonneIlk, 37044 Tours, France
Accepted7 August1994
Among the many causes of sciatica, endome~osis, a rare aetiology, should be considered in ~enst~ting women in view of the diagnostic strategy and ensuing therapeutic implications. We report a case of sciatic nerve involvement with endometriosis in contact with the nerve in the left sciatic notch. Exploration by MRI was invaluable for the diagnosis, revealing a signal on the stem of the nerve suggestive of a lesion with haemorrhagic content. Keywurdr: Endometriosis; Sciatica; MRI
1. Introduction
Endome~osis is a rare cause of sciatica. Since the tirst case of endometriosis-induced sciatica reported by Schlicke in 1946 [ 11, 18 histologically proven observations have been reported. For four of them [2-51 computed tomography (CT) of the pelvis revealed a lesion on the sciatic nerve. None of these patients underwent magnetic resonance imaging (MRI). We report a case of sciatic nerve involvement explored by MRI, with endometriosis in contact with the nerve in the left sciatic notch. 2. case report A 39-year-old woman {gravida 1, para 1) was referred for episodic pain in her back and left leg associated with difficulties in walking, of slow progressive onset. Clinical history revealed cyclic left sciatica which had evolved * Corresponding author.
over 3 years. Pain began on the first day of menstruation and continued for the 5 or 6 days of menstruation. It was poorly controlled by non-steroid anti-inhalator drugs. The pain recurred during the following cycle after a pain-free period. CT scan of the lumbar vertebrae 6 months before had shown only a slightly bulging L-5-S 1 disc. On examination, she walked with left steppage gait. There was paralysis of the anterior tibia1 and peroneal muscles of the left ieg associated with hypoesthesia in the L-5 area. Left straight leg-raising did not produce discomfort (no Lasegue’s sign). Achilles reflex of the left contirmed foot was not present. Electromyogram damage to the peroneal nerve with slight damage to the tibia1 nerve. Truncal sciatica was suspected and pelvic MRI revealed a distinct mass of approximately 2 cm in diameter in the left sciatic notch (Fig. 1). The lesion appeared to be situated in the lower part of the piriform muscle, in contact with the sciatic nerve in the gluteal area. The lesion was hy~~nten~ on the Tl and T2 weighted images, partially surrounded by a
0 1995 Elsevier Science Ireland Ltd. All rights reserved 0028.2243/95/$09.50 SSDI 0028-2243(94)01946-5
200
Ph. Descamps et al. /European Journal Obstetrics & Gynecology and Reproduction Biology 58 (1995) 199-202
Fig. 1. Post-gadolinium coronal Tl-weighted image showing the lesion close to the sciatic nerve (arrowhead).
thin hypointense zone in both ponderations. The lesion was not enhanced by gadolinium injection. Surgery revealed a purplish mass situated within the piriform muscle, developing below and outside in contact with the sciatic nerve. The whole region was inflamed. Section of the tumour released a chocolate coloured fluid. Preliminary examination indicated the diagnosis of endometriosis. The cyst was excised and neurolysis of the sciatic nerve was performed. A pathological examination (Fig. 1) revealed areas of typical endometrial glands s~round~ by stroma and bordered by vessels with occasional foci of hemosiderin-laden macrophages typical of endometriosis. Ultrasonography and laparascopy revealed no other pelvic localisations. Treatment with Cn-RH agonist (Triptorelin, 3.75 m~month) was prescribed for 3 months followed by Promegeston (0.5 mg). All pain had disappeared on completion of treatment. Electromyelogram performed 5 months after surgery revealed initial neurologic recovery. 3. Discussion Endometriosis is defined by the presence of ectopic
islets of endometrial tissue. It is a very common gynaecologycal disease affecting between 1% and 5% of women of reproductive age [6] but its true frequency is difficult to estimate because in many cases there is no parallel between anatomical lesions and clinical features. The localisation of endometrial nodes at the root of a nerve or in the nerve stem is one of the rarest topographical variations of this condition. The precise pathogenesis of endometrial sciatica is still unknown. The existence of a peritoneal diverticulum permitting endomet~al tissue to migrate to the sciatic nerve from the site of genital endometriosis or after tube reflux has been suggested [7], but this ‘pocket’ sign is rarely observed during pelvic examination. Haematogenic migration after vascular damage such as a slight injury or surgery could also be the cause, especially in patients without other sites of endometriosis. As endometriosis is hormone dependent, the haemorrhage penetrates neighbouring tissues during each menstrual cycle and triggers a considerable in~a~atory reaction. All the published cases give the same descriptions of pain [2,8]. The sciatica is first cyclical and occurs during menstrual periods. It sometimes begins l-2
ph. Descamps ef al. /European Jomai
Obstetrics & Gynecology and Reproduction Biology S8 (1995) 199-202
days before or after the first day of a period. The pain is intense and progressive, with a pain-free interval which gradually shortens until, after a few years, it becomes permanent. Although, in one case 191 pain disappeared during pre~an~y (which is classic of all endometriosis symptoms), in all other published cases it had no effect on the sciatic pain [2]. There is a clear predominance of sciatic pain on the right side [S]. It has been suggested that the sigmoid impedes the implantation of endometriosis nodes on the left sciatic nerve. Sensorimotor deficit can appear. Such progressive sensory motor deficit is sometimes the only manifestation of sciatic nerve involvement. Straight leg-raising producing discomfort (Lasegue’s sign) is often present and tenderness in the sciatic notch is often elicited. There may be weakness and atrophy of muscles innervated by the sciatic nerve, and appropriate sensory loss [2]. Pelvic exa~nation is usually normal, but foci of endometriosis may be seen or palpated (in one case, palpation of the utero-sacral ligament produced sciatic neuralgia) [9]. Elec~omyogram can identify peripheral neuro~enous syndrome by showing signs of denervation as well as slowing of conduction speed. Moreover, it makes possible the distinction between root and stem damage and the surveillance of treatment after evolution. In different pelvic localisations, endometriosis presents different aspects on CT scan: cystic, solid or mixed. There have been some reports of CT scans of endometriosis-induced sciatica [2-51 but, to our knowledge, none of MRI exploration of catameniai sciatica. The sensitivity and specificity of this technique in the diagnosis of endometriosis in usual pelvic localizations (ovaries and uterus) is estimated to be around 700/o [ 10,l I]. These cystic lesions are typically surrounded by an hypointense rim on Tl and T2 weighted images related to their fibrous capsule (121. Classically, the interior of the cyst is hyperintense in Tl and T2 weighted images due to the presence of paramagnetic methemo~obin, There can be other types of signal: hypointensity in both sequences or hypointensity on Tl weighted images associated with hyperintensity on T2 weighted images [lO,ll]. The intensity of the signal is a function of the quantity and age of the hemorrhage on the one hand and of the pro~rtion of endomet~al cells and stroma on the other hand. In our case, the lesion presented h~rintensity on both ~nderal sequences related to its hematic content and a peripheral hypointensity which could have been linked to the presence of fibrous tissue and granular tissue composed of macrophages filled with hemosiderin. In view of the nerve symptomatology and the topography of the lesion, the principal differential diagnosis is benign neurogenic tumour. On MRI [ 131 neurinoma and neurofibroma are hypointense in the ponderal sequence in Tl and heterogeneously hyper-
201
intense in the ponderal sequence in T2 (with a central zone of low intensity for neuro~bromas). These trots are usually greatly enhanced after gadolinium injection. In the few observations of cystic forms of these tumours, the signal was never hy~~ntense in the ponderal sequence in Tl [14]. The ~tameni~ rhythm in our case of pain associated with the signal from the lesion (hyperintensity on Tl and T2 weighted images as in the signal from ovarian endometriosic cysts, absence of enhancement after gadolinium injection) should first suggest a diagnosis of endometriosis. Treatment is based on excision of the lesion in contact with the sciatic nerve (confirming the diagnosis and giving the best chance of neurological recovery) and associated treatment of the other localizations of endometriosis (laparoscopic surgery and/or medical treatment, particularly with GnRH agonists). Therefore, endometriosis may result in chronic sciatica which is catamenial and increases in intensity and duration during successive cycles to the point of ~coming reagent. MRI may support the diagnosis by revealing a signal on the stem of the nerve suggestive of a lesion with haemorrha~~ content.
We wish to express our gratitude to Professor D. Sirinelli for his help and to Mrs D. Raine for her ~ng~sh lecture. References Schlicke CP. Ectopic endometrial tissue in the thigh. J Am Med Assoc 1946; 132: 445. Saiazar-Grueso E, Roos R. Sciatic endometriosis: a treatable sensorimotor mononeuropathy. Neurology 1986; 36: 1360-1363. Hibbard J, Schreiber JR. Footdrop due to sciatic nerve endometriosis. Am J Obstet Gynecol 1984; 149: 800-801. Fishman EK, Scatarige JC, Satsouk FA, Rosenhein NB, Siegelman SS. Computed tomography of endometriosis. J Comput Assist Tomogr 1983; 7: 257-264. Richards BJ, Gillet WR, Polloc KM. Reversal of footdrop in sciatic nerve endometriosis. J Neurol Neurosurg Psychiatry 1991; 54: 935-940. Barbieri R.L. Endometriosis 1990. Current treatment approaches. Drugs 1990; 39: 502-510. Hedd HB, Welch JS, Mussey E et al. Cyclic sciatica: report of a case with introduction of a new surgical sign. J Am Med Assoc 1962; 180: 521. Torkelson SJ, Lee RA, Hildahl DE. Endrometriosis of the sciatic nerve: a report of two cases and a review of the litterature. Gbstet Gynecoi 1988; 71: 473-477. Dagnehe J. Lombo-sciatalgie et endocrinologie: contribution B t’&ude des endom~triomes h~t~rotopiques. Ann Endocrinoi 1947; 8: 26-31. Arrive L, Hricak H, Martin MC. Pelvic endometriosis: MR imaging. Radiology 1989; 171: 687-692. Zawin M, McCarthy S, Scoutt L, Comite F. Emodometriosis: appearance and detection et MR imaging. Radiology 1989; 171: 693-696.
202 [I21 Nishimura
Ph. Descomps et al. /European Journal Obstetrics & Gynecology and Reproduction Biology 58 (1995) 199-202
K, Togashi K, Itohk, Fujisawa I, Noma S, Kawamura Y et al. Endometrial Cysts of the ovary: MR imaging Radiology 1987; 162: 315-318. [13] Suh JS, Abenoxa P, Galloway HR, Everson LI, Grifiths HJ. Peripheral (extracranial) nerve tumors: correlation of MR imaging and histological findings. Radiology 1992; 183: 341-346.
[14] Cerofolini E, Landi A, DeSantis G, Maiorana A, Canossi G, Romagnoli R. MR of benign peripheral nerve sheath tumors. J Comput Assist Tomogr 1991; 15: 593-597.