Citations

Abstract OBJECTIVE AND IMPORTANCE Heterotopic ossification (“neuritis ossificans”) is among the least frequently encountered reactive lesions in peripheral nerves. Only two cases have been described previously, one in the median nerve of a 34-year-old man, and the other in the ulnar nerve of an adult woman. The architecture of this lesion is distinctly zonal. Consisting of a central fibroblastic core, an intervening zone of osteoid production, and a peripheral layer of ossification, the pattern is remarkably similar to that of myositis ossificans. This similarity and the occurrence of the process in superficial nerves have led to speculation that trauma plays a role in its pathogenesis; this hypothesis remains unproved. We describe two additional cases of neuritis ossificans. CLINICAL PRESENTATION One patient, a 41-year-old man, experienced pain and numbness in the left leg for several months but had no history of local trauma. A mass was detected in the saphenous nerve. The second patient, a 16-year-old boy, noted subacute onset of pain in the popliteal fossa and decreased sensation in the distribution of the lateral sural cutaneous nerve. A mass was found within the tibial nerve at the knee level. INTERVENTION In each patient, resection of the mass required sacrifice of a segment of the nerve. CONCLUSION In each patient, the mass was composed of fibrovascular tissue with osteoid and bone deposition arranged in a zonal pattern. The ossifying process was intraneural but encased rather than directly involving nerve fascicles. These exceptionally intact examples of neuritis ossificans underscore its resemblance to myositis ossificans. Nerve-sparing resection of such masses is not always possible.

Abstract OBJECTIVE AND IMPORTANCE We report the case of a 29-year-old man with Gardner syndrome and an isolated, giant cerebellopontine angle craniopharyngioma. Our description of this patient is only the second case report of a craniopharyngioma arising primarily in the cerebellopontine angle. CLINICAL PRESENTATION The patient presented with a 1-year history of progressive neurological impairment and headache. On the basis of the patient's history of multiple dermal fibromas, a cranial osteoma, familial adenomatous polyposis (FAP), a total abdominal colectomy, and an adenoma of the ampulla of Vater, we diagnosed the patient's condition as Gardner syndrome. INTERVENTION Magnetic resonance imaging showed a large cerebellopontine angle tumor, which was removed through a suboccipital retromastoid craniotomy. The pathological features were those of an adamantinomatous craniopharyngioma. The patient has done well postoperatively and has no new neurological deficits. A careful retrospective review of the preoperative imaging shows that this tumor was located exclusively in the posterior fossa and was not an extension of a sellar, suprasellar, or clival craniopharyngioma. CONCLUSION We present the second reported case of FAP and craniopharyngioma. There is no known genetic link between FAP and craniopharyngioma. Now that the patient has manifested a primary tumor of the central nervous system with FAP, it is unclear whether he should be classified as having Turcot syndrome. For this patient, we recommended vigilant follow-up imaging and forgoing external beam radiotherapy unless there is a documented recurrence of his craniopharyngioma.

Abstract OBJECTIVE AND IMPORTANCE Cerebellar hemorrhage remote from the site of surgery may complicate neurosurgical procedures. We describe our experience with two cases of cerebellar hemorrhage after spinal surgery and review the three cases previously reported in the literature to determine whether these cases provide insight regarding the pathogenesis of remote cerebellar hemorrhage. CLINICAL PRESENTATION One of our patients developed cerebellar hemorrhage in the vermis and right hemisphere after transpedicular removal of a partially intradural T9–T10 herniated disc with the patient in the prone position. The other patient developed cerebellar hemorrhage in the vermis and bilateral hemispheres after L3–S1 decompression and instrumentation with the patient in the prone position, during which the dura was inadvertently opened. INTERVENTION The first patient was treated conservatively and had mild residual dysarthria and gait ataxia 2 months after surgery. The second patient underwent exploration and revision of the lumbar wound with primary dural repair. The cerebellar hemorrhage was treated conservatively, and the patient had mild dysarthria and ataxia 1 month after surgery. CONCLUSION Cerebellar hemorrhage must be considered in patients with unexplained neurological deterioration after spinal surgery. Dural opening with loss of cerebrospinal fluid has occurred in every reported case of cerebellar hemorrhage complicating a spinal procedure, supporting the hypothesis that loss of cerebrospinal fluid is central to the pathogenesis of this condition. Because remote cerebellar hemorrhage can occur after procedures with the patient in the supine, sitting, and prone positions, patient positioning seems unlikely to play a causative role in its occurrence.

Abstract OBJECTIVE AND IMPORTANCE: Optic nerve choristoma is a rare lesion composed of adipose tissue and smooth muscle involving the optic nerve. Few cases have been reported. CLINICAL PRESENTATION: A 20-year-old woman presented with a history of slowly progressive visual loss in the left eye. On T1-weighted magnetic resonance imaging studies, after frequency-selective fat saturation, an optic nerve mass was detected at the level of the optic canal with signal characteristics suggesting the diagnosis of optic nerve lipoma. INTERVENTION: At left frontotemporal craniotomy, the intracranial optic nerve appeared thin and atrophic proximally and was covered by abundant adipose tissue distally. Because no cleavage plane could be identified between the fatty lesion and the optic nerve, which appeared splayed within the adipose tissue, the nerve was resected after an intraoperative biopsy. The presence of two heterotopic mesodermal elements, a rim of adipose tissue admixed with bundles of mature smooth muscle, extending into the nerve septa, warranted a diagnosis of optic nerve choristoma. CONCLUSION: Optic nerve choristoma is an uncommon optic nerve lesion. Even if imaging studies are highly suggestive of the diagnosis, pathological confirmation is required because of the high adipose tissue content in the majority of cases. The lesion, most likely malformative and nonneoplastic in nature, can be the cause of progressive visual loss.

AbstractOBJECTIVE:The purpose of this study was to describe the natural history of tethered cord in patients who have undergone meningomyelocele repair.METHODS:We performed a retrospective review of 45 patients with a history of neonatal meningomyelocele repair who subsequently developed symptoms of tethered cord. Symptoms of tethered cord in this cohort consisted of the development of bladder spasticity or orthopedic foot deformity. None of these patients were treated with cord untethering; instead, they were treated symptomatically.RESULTS:On follow-up, 40 (88.9%) of these patients subsequently required additional orthopedic or urological procedures because of further symptoms of tethered cord. The incidence of progression of tethered cord syndrome is 27.5, 40, and 60% at 1, 2, and 5 years, respectively.CONCLUSION:Although this study does not address the question whether cord untethering will prevent further symptom development, these results do provide a strong rationale for consideration of an untethering procedure in patients with repaired meningomyelocele at the time of the onset of symptoms of tethered cord.

Abstract OBJECTIVE AND IMPORTANCE A case of acutely symptomatic epidural hematoma caused by metastatic hepatocellular carcinoma (HCC) to the cranium is reported. This is a rare case of metastatic HCC without known primary presenting as an epidural hematoma. CLINICAL PRESENTATION The patient presented with an acute onset of headache, aphasia, and right hemiparesis 2 weeks after he experienced minor trauma to the cranium. An emergency computed tomographic scan of the head revealed the presence of a left parietal epidural hematoma. INTERVENTION An emergency evacuation of the epidural hematoma was performed, and metastatic HCC was diagnosed. CONCLUSION The patient's neurological deficits were reversed with surgical intervention, and he is now undergoing palliative chemotherapy. This was the first clinical manifestation of HCC in this patient. This case reaffirms the neurosurgeon's role in the complex, multidisciplinary care of patients with craniospinal metastasis.

Abstract OBJECTIVE The proper treatment for patients with cyst formation after arteriovenous malformation radiosurgery is unknown. METHODS The treatment of six patients who developed cysts after arteriovenous malformation radiosurgery is described. Four patients had undergone gamma knife radiosurgery (two patients developed cysts after repeat procedures), and two patients had undergone linear accelerator-based radiosurgery. The median prescription isodose volume at the time of the first radiosurgical procedure was 13.2 cm3 (range, 8.0–28.7 cm3). RESULTS The cysts were discovered a median of 48 months (range, 24–89 mo) after radiosurgery. Three patients were originally without symptoms, and observation with serial imaging was performed; two of those patients developed symptoms 13 and 40 months later, whereas one patient has remained without symptoms for 51 months. Initial treatments for patients with symptomatic cysts included cyst aspiration (n = 3) and placement of a cystoperitoneal shunt (CPS) (n = 2). The median cyst volume was 14 cm3 (range, 4–63 cm3). Cyst recurrence occurred within 2 months for patients who underwent aspiration alone, necessitating placement of a CPS. Shunt placement eliminated the cysts for four patients, at a median follow-up time of 16 months (range, 9–27 mo). One patient's cyst persisted despite CPS placement, and cyst excision was performed. No morbidity occurred with any of the cyst treatments. CONCLUSION Cyst formation after arteriovenous malformation radiosurgery may occur many years after the procedure. Although most symptomatic cysts can be effectively treated with CPSs, cyst excision may be necessary if the mass effect is not relieved with the less invasive approach.