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Richard L. Davis and Gerald E. Fox

✓ Mucin-producing cystic tumors of the choroid plexus are rare and most are papillomas or carcinomas. An acinar choroid plexus adenoma of the right lateral ventricle is described. Symptoms and signs included headache, vomiting, papilledema, and a gait disturbance. The neoplasm was located with ventriculography and totally removed, but the patient died of complications of surgery. The relationship of this tumor to others arising in the choroid plexus is discussed.

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Samuel F. Ciricillo, Richard L. Davis and Charles B. Wilson

✓ The authors report the case of a patient harboring a posterior fossa neuroepithelial cyst who presented with positional facial weakness and syncope. The patient recovered rapidly after cyst fenestration and placement of an internal cyst-cisternal shunt. The pathogenesis and principles of diagnosis and management of these rare lesions are reviewed.

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Charles E. Alpers, Richard L. Davis and Charles B. Wilson

✓ A 5-year-old girl with juvenile pilocytic astrocytoma subsequently had multiple episodes of symptomatic recurrence over the course of 21 years of follow-up review. This lesion underwent histological transformation to an anaplastic small-cell neoplasm 21 years after the initial resection and diagnosis. Late transformation of benign childhood cerebellar astrocytomas to malignant astrocytic tumors is very rare; transformation to an anaplastic small-cell neoplasm has not been reported previously. This case and other reported cases in which juvenile pilocytic astrocytoma recurred after a long interval indicate the requirement of long-term follow-up review of these patients before assuming either a cure or arrest of the tumor's growth.

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Adam N. Mamelak, William M. Kelly, Richard L. Davis and Mark L. Rosenblum

✓ Hypertrophic cranial pachymeningitis is a rare, idiopathic form of granulomatous pachymeningitis. This report describes three cases of hypertrophic cranial pachymeningitis and discusses the clinical, radiographic, and pathological findings in these and other reported cases. These lesions typically cause progressive cranial nerve palsies, headaches, and cerebellar dysfunction. They occur in patients of all age groups; the peak incidence is in the sixth decade. Hypertrophic cranial pachymeningitis is best identified by magnetic resonance imaging. The diagnosis is established by excluding all other granulomatous and infectious diseases. A dural biopsy is essential to confirm the diagnosis. Hypertrophic cranial pachymeningitis is initially responsive to steroid therapy, but in most cases it recurs or progresses despite treatment. Surgical excision of granulomas is occasionally necessary to alleviate a mass effect. The long-term outcome remains uncertain for most patients, but progressive disease is usually fatal owing to cranial neuropathies.

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James E. Boggan, Richard L. Davis, Greg Zorman and Charles B. Wilson

✓ The authors report the uncomplicated removal of an intrasellar epidermoid cyst that on presentation mimicked a pituitary adenoma. Current controversies regarding the differentiation of this cyst from other cystic lesions of the sellar region are reviewed.

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Isabelle M. Germano, Michael S. B. Edwards, Richard L. Davis and Davide Schiffer

✓ Meningiomas arising in the first two decades of life are uncommon and their characteristics are controversial. Some authors believe meningiomas in younger patients occur in different locations, have more malignant histological features, and have a worse prognosis than those in adults. To address this controversy, the authors retrospectively reviewed 23 cases of meningiomas in patients under 21 years of age at diagnosis who were operated on at the University of Turin (1948 to 1990) or at the University of California, San Francisco (1970 to 1989). These tumors represented 2.9% of all tumors in this age group and 1.8% of all meningiomas during the study period at the two institutions. There were 14 males and nine females. The mean age at surgery was 13.3 ± 5.6 years; nine cases occurred in the first decade and 14 in the second. The most common neurological symptoms were a focal neurological deficit (33%) and seizures (25%). Seventy percent of the tumors were supratentorial. A gross total resection was performed in 60% of the cases. Histologically, the majority (74%) of the tumors were meningothelial or mixed. An increased number of mitoses was observed in 33% of the tumors, focal necrosis in 29%, and invasion of adjacent brain in 14%; however, none of the tumors was classified as a Grade III (anaplastic) meningioma. All patients are alive without evidence of recurrent disease 3 to 22 years (mean ± standard deviation: 10 ± 7.3 years) after surgery. This study confirms the rarity of meningiomas of the first two decades of life and the absence of the female predominance associated with meningiomas in adults. The location and histological features of these tumors are similar to those in adults; they have a low recurrence rate, and the outcome and survival rate are excellent.

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Isabelle M. Germano, Richard L. Davis, Charles B. Wilson and Grant B. Hieshima

✓ Embolization with polyvinyl alcohol (PVA) is an accepted method of rendering complex arteriovenous malformations (AVM's) more amenable to surgery, but its effects on human vascular tissues have not been adequately documented. The authors reviewed the histopathology of 66 intracranial AVM's resected 1 to 76 days after embolization with PVA. The mean age of the patients was 36 years, and their AVM's were located in the cerebral hemispheres (92%), the cerebellum (6%), or the corpus callosum (2%). In 79% of cases, at least one vessel contained PVA particles; in most cases, the vessel was filled with sharp, angular PVA particles in a serpiginous pattern. Polyvinyl alcohol particles indented the endothelium in 69% of cases but were rarely found subendothelially. Clotted blood and fibroblasts were present among the particles, and abundant intraluminal mononuclear and polymorphonuclear inflammatory cells were found in all vessels containing PVA particles. Foreign-body giant cells appeared 2 to 14 days after embolization in the majority of cases. Patchy mural angionecrosis and necrotizing vasculitis were found in 39% of the cases. Recanalized lumina were seen in 18% of PVA-embolized vessels. Foreign materials resembling cotton fibers and other particulate substances, which were probably contaminants of the contrast solution or the embolic material, were found in 65% of the cases. These findings suggest a specific chain of events in the interaction between PVA and vessel wall components and may explain some important sequelae of embolization therapy.

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Hendrikus G. J. Krouwer, Richard L. Davis, Pamela Silver and Michael Prados

✓ Although gemistocytic astrocytomas are considered slow-growing astrocytomas, they often behave aggressively. To clarify the biological and clinical behavior of these rare tumors, the authors retrospectively identified 59 patients with gemistocytic astrocytoma whose tumors were diagnosed and treated between June, 1976, and July, 1989. Three patients who were lost to follow-up review were excluded, as were two whose original slides could not be obtained and three whose tumors were diagnosed at recurrence or at autopsy. The pathological material of the remaining 51 patients was reviewed using two sets of histological criteria.

Thirteen patients (Group A) had “pure” gemistocytic astrocytoma, defined as a glial tumor with more than 60% gemistocytes/high-power field and a background of fibrillary astrocytes. Fifteen patients (Group B) had “mixed” gemistocytic astrocytoma, defined as a glial tumor with 20% to 60% gemistocytes/high-power field and a background of anaplastic astrocytes. Twenty-three tumors did not meet these criteria and were excluded from analysis. The median age of the patients was 48.5 years in Group A and 38.3 years in Group B (p < 0.05). In both groups, the median Kamofsky Performance Scale score was greater than 90%. All patients underwent surgical procedures (four total and 19 partial resections, and five biopsies) and postoperative radiation therapy. The majority also had interstitial brachytherapy, chemotherapy, or both. Ten patients had one reoperation for tumor recurrence and one had two reoperations; other treatments for recurrence included brachytherapy, chemotherapy, and repeat irradiation. All four patients who originally underwent gross total resection are still alive; all five who had a biopsy have died. There was no significant difference in median survival times between groups: 136.5 weeks in Group A (range 10 to 310+ weeks) and 135.6 weeks in Group B (range 31 to 460+ weeks). Analysis of all 28 patients showed a better prognosis for patients less than 50 years of age (185 vs. 36 weeks survival time; p < 0.001), patients with preoperative symptoms lasting for more than 6 months (228.1 vs. 110.2 weeks survival time; p < 0.05), and patients with seizures as the first symptom (185.7 vs. 80 weeks survival time; p < 0.01). Survival time did not correlate with the presence of perivascular lymphocytic infiltration.

The authors conclude that the presence of at least 20% gemistocytes in a glial neoplasm is a poor prognostic sign, irrespective of the pathological background. It is proposed that gemistocytic astrocytomas be classified with anaplastic astrocytomas and treated accordingly.

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Robert B. King, Richard L. Davis and George H. Collins

✓ The authors review the case of a patient treated by Dr. Walter Dandy. When the patient was a young child he underwent two right transtemporal third ventriculostomies during which he sustained an unrecognized contralateral subdural hygroma and a chronic subdural hematoma with a mild infantile hemiparesis. He was able to complete high school, albeit at a slower pace than usual. As an adult he held several limited employment positions, lived at home for several decades, and was later cared for at a nursing home for a short time. The patient died when he was 66 years of age.