Occult leptomeningeal large cell medulloblastoma in an adult.

OBJECTIVE AND IMPORTANCE: Large cell medulloblastoma is an uncommon malignancy of childhood that often pursues an aggressive clinical course. We report the first case of this entity in an adult that proved to be an unsuspected primary leptomeningeal tumor. CLINICAL PRESENTATION: A 30-year-old man complained of worsening neck pain over the course of 3 months. Neck pain increased a few days prior to admission and a cervical spine CT revealed tonsillar herniation. Cervical spine MRI performed the day prior to admission confirmed the diagnosis of Chiari I malformation and C3-4 disk herniation without spinal cord compression. On the day of admission, the patient became unresponsive and resuscitative measures were unsuccessful. Postmortem examination of the brain was notable for necrotic cerebellar tonsils, but demonstrated no evidence of an intraparenchymal mass lesion. Microscopic examination of the cerebellum revealed discohesive neoplastic cells, which showed characteristic dot-like immunoreactivity for synaptophysin, diagnostic of large cell medulloblastoma within the subarachnoid space. CONCLUSIONS: Our experience with this unique case illustrates the challenges of diagnosing a primary leptomeningeal neoplasm. This case also underscores the importance of maintaining a high degree of suspicion for leptomeningeal neoplasms in patients who present with imaging studies suspicious for Chiari I malformation.

Intracranial neurenteric cysts: imaging and pathology spectrum.

BACKGROUND AND PURPOSE: Intracranial neurenteric (NE) cysts are rare congenital lesions that may be mistaken for other, more common non-neoplastic cysts as well as cystic neoplasms. We delineate the imaging spectrum, pathologic findings, and differential diagnosis of NE cysts. METHODS: History, imaging, surgical and pathologic findings were analyzed retrospectively in 18 patients with intracranial NE cysts. Fifteen were surgically proved cases; 3 exhibited classic imaging findings and are being followed clinically. RESULTS: Thirteen cysts were located in the posterior fossa; 12 of 13 were extra-axial. Size varied from 1.2 x 0.8 x 0.6 cm to 3.4 x 3 x 2.5 cm. Five were supratentorial, measuring from 7 x 5 x 3 to 9 x 6 x 7 cm. All were frontal and off the midline. Seven of 18 patients had CT scans. Cysts varied widely in attenuation. None enhanced. Eighteen of 18 had MR images. Sixteen of 18 were hyperintense, and 2 were isointense to CSF on T1-weighted imaging. Sixteen of 18 were hyperintense on T2-weighted imaging. All cysts were hyperintense to CSF on fluid-attenuated inversion recovery (FLAIR) sequences. Diffusion imaging was performed on 2 patients. One case showed mild restriction. Mild posterior rim enhancement was seen in 5 cases at the site where the cyst adhered to brain parenchyma. CONCLUSION: The imaging spectrum for NE cysts is broader than previously reported. Intracranial NE cysts should be considered in the differential diagnosis for intracranial extra axial cystic lesions both above and below the tentorium.

Cortical blindness after metrizamide myelography. Report of a case and proposed pathophysiologic mechanism.

Metrizamide, a nonionic, water-soluble contrast medium, has been increasingly used for myelography. We saw a patient with cortical blindness, seizure, organic psychosis, and asterixis after undergoing attempted metrizamide myelography via C1-2 puncture. Computed tomography demonstrated early penetrance of metrizamide into the brain parenchyma, most prominently in the occipital lobes. A mechanism of direct metrizamide neurotoxicity was proposed.

Educational efficacy of computer-assisted instruction with interactive videodisc in radiology.

RATIONALE AND OBJECTIVES: To create a robust, functional computer-assisted instruction (CAI)-videodisc program and to demonstrate its educational efficacy. METHODS: After creating a CAI-videodisc program in skeletal radiology for a two-screen Macintosh system, 36 medical students and 162 radiology residents entered a controlled study with paired pre- and posttests. Subjects also compared CAI-videodisc with other educational media. RESULTS: Medical students using the CAI-videodisc improved their mean pre- and posttests. Subjects also compared CAI-videodisc with other educational media. RESULTS: Medical students using the CAI-videodisc improved their mean pre- and posttest scores from 50.9 to 70.9 (P < .001, control group scores 50.1 and 50.6) and residents (using a different test) improved from 45.4 to 70.9 (P < .001, control group scores 49.6 and 46.1). Medical students and residents favored CAI-videodisc over teaching files, textbooks, videotapes, and slide-audiotapes. CONCLUSIONS: A functional CAI-videodisc program was created and demonstrated to be educationally effective.

Intracranial hemangiopericytomas: MR and CT features.

PURPOSE: To describe the MR and CT imaging features of hemangiopericytoma and to identify the characteristics that might distinguish them from meningioma. METHODS: We retrospectively reviewed the CT and MR findings in 34 pathologically proved cases of hemangiopericytoma. We evaluated the size, shape, and location of the tumor; the presence of hydrocephalus, edema, and mass effect; the type of dural attachment (broad-based or narrow-based) and bone changes (erosion, hyperostosis); and the tumor's density, signal, and contrast-enhancement characteristics. RESULTS: Thirty of 34 tumors were 4 cm or more in greatest dimension, 32 were lobular, and only seven were in the posterior fossa. Hydrocephalus was present in 18, edema in 30, and mass effect in 33. Twenty-three had broad-based dural attachment and 11 had narrow-based attachment. All 26 unenhanced CT scans showed hyperdense tumors; 19 were heterogeneous and seven homogeneous. All 27 contrast-enhanced CT scans showed enhancement; 17 were heterogeneous and 10 homogeneous. Bone erosion was present in 17 of 29 hemangiopericytomas imaged with CT. None had hyperostosis or tumor calcifications. On T1-weighted MR images, 13 of 17 tumors were isointense with cortical gray matter; on T2-weighted image, 10 of 17 were isointense. All 14 tumors imaged with contrast enhanced T1-weighted MR imaging showed enhancement, and 13 of these were heterogeneous; eight of the 14 had a "dural tail" sign. CONCLUSION: Intracranial hemangiopericytomas are multilobulated, extraaxial tumors, sometimes associated with narrow-based dural attachment and bone erosion. Unlike with meningiomas, hyperostosis and intratumoral calcification are not present.

CT of the brain in taste and smell dysfunction.

Three hundred fifty-four patients with taste and/or smell disorders were evaluated with computed tomography (CT). The largest group was characterized by head trauma (27%), followed by idiopathic causes (26%), postinfluenza-like hyposmia and hypogeusia (15%), and congenital etiologies (14%). Hyposmia and hypogeusia occurred concomitantly in 21%-45%, the percentage varying according to etiologic subgroup. CT abnormalities were found in 108 (31%) of the 354 patients. The most frequent pathologies were frontal encephalomalacia, subfrontal atrophy in the region of the olfactory bulbs, and anterior temporal lobe atrophy. These changes were found alone or in tandem. Some CT findings suggest common cerebral taste and smell centers and common neural pathways and association centers.

Congenital brain tumors: a review of 45 cases.

Forty-five pathologically proved cases of neonatal brain tumors (diagnosed in neonates within 60 days after birth) were reviewed from the neuroradiology archives dating back to 1964. CT was performed in 24 cases, MR in five, sonography in six, and angiography in seven. Two-thirds of the lesions were supratentorial. The most common histology was a tumor composed of primitive or poorly differentiated tissues: 12 teratomas and 12 primitive neuroectodermal tumors, four of which were typical medulloblastomas. In addition, there were nine astrocytomas (grades I-III); four cases of glioblastoma multiforme (astrocytoma grade IV); three choroid plexus papillomas; and single cases each of ependymoma, medulloepithelioma, germinoma, angioblastic meningioma, and ganglioglioma. The dominant CT appearance, regardless of histology, was a large heterogeneous lesion with associated hydrocephalus. Coarse calcification was a constant feature in the teratomas. Prognosis was poor overall, with the longest survival seen in choroid plexus papilloma and astrocytoma. Imaging studies are most valuable in identifying and distinguishing potentially curable lesions such as choroid plexus papillomas (variably sized intraventricular lesions with homogeneous enhancement) from rapidly fatal tumors such as teratomas (large heterogeneous lesions with coarse calcifications and associated hydrocephalus).

Lateral ventricular neoplasms of the brain: differential diagnosis based on clinical, CT, and MR findings.

The differential diagnosis of lateral ventricular tumors was explored by retrospective analysis of 47 pathologically proved cases identified by CT and/or MR imaging. Third ventricular tumors adjacent to the foramen of Monro (e.g., colloid cysts) were excluded. Forty-six patients underwent CT, and eight had MR imaging. The most common neoplasms were choroid plexus papilloma (10 cases) and meningioma (nine cases). Other common neoplasms included subependymoma (six cases), subependymal giant cell astrocytoma (five cases), and metastasis/lymphoma (four cases). Important features for differential diagnosis included age of the patient, the tumor's location within the lateral ventricle, and density on CT before IV administration of contrast material. Fifty percent of the tumors were in the ventricular atrium. All intraventricular tumor types (except subependymoma) showed contrast enhancement. MR was most useful in evaluating tumor location, size, and extent, but it did not help in eliminating alternative diagnoses. On the basis of patients' ages, specific tumor location, and the appearance on CT scans or MR images, an algorithm for differential diagnosis of lateral ventricular tumors was developed.

Radiologic-pathologic correlation. Epidermoid tumor of the cerebellopontine angle.

This case demonstrated the classic gross pathologic, CT, and MR appearances of epidermoid tumors. The imaging features and differential diagnosis are summarized.

Cerebral MR imaging in intravascular lymphomatosis.

MR imaging data were reviewed retrospectively in four male patients (32 to 74 years old) with histologically confirmed intravascular lymphomatosis (IVL), a rare, aggressive form of non-Hodgkin lymphoma. MR findings included infarct-like lesions (n = 2), focal parenchymal enhancement (n = 3), dural/arachnoid enhancement (n = 2), and, in one case, nonspecific, patchy foci of increased signal in the white matter on long-TR images. All patients had multifocal lesions. Knowledge of the spectrum of MR imaging features in this unusual disorder may aid in diagnosis and potentially enhance the role of imaging in following response to therapy.

Thin-section CT of midbrain abnormalities in progressive supranuclear palsy.

Thin-section computed tomographic (CT) scans of 3 and 1.5 mm thickness were obtained using the Philips Tomoscan 310 and General Electric 8800 CT/T scanners in the study of 10 consecutive patients with progressive supranuclear palsy (PSP) and 31 patients with other diseases. Marked midbrain and moderate pontine atrophy, a dilated third ventricle, and enlarged quadrigeminal plate cisterns were observed in all PSP cases. The aqueduct was dilated in several. In six of the PSP cases, there was a striking midbrain abnormality in the form of a low-density area extending from the interpeduncular cistern toward the aqueduct. Thin-section metrizamide-enhanced cisternography of three of the six PSP cases showed that the low-density abnormality was the result of the interpeduncular cistern invaginating the atrophic midbrain.

The interventricular extension of choroid plexus papillomas.

Four cases of choroid plexus papilloma extending through the foramen of Monro are presented. All four patients were evaluated by contrast-enhanced CT and two of these were also evaluated by neurosonography. No other intraventricular tumor commonly extends through a ventricular outlet. The radiographic demonstration of this extension of an intraventricular mass through the foramen of Monro, cerebral aqueduct, or foramen of Luschka or Magendie represents an ancillary diagnostic sign of choroid plexus papilloma.

Radiologic-pathologic correlation. Diffuse pontine astrocytoma.

This case demonstrated the classic gross, pathologic, CT, and MR findings of pontine astrocytoma. The role of functional brain imaging in identifying regrowth of tumor was illustrated and the differential diagnosis of a brain stem lesion summarized.

Chondrosarcoma of the larynx: CT features.

PURPOSE: To define the typical CT features of chondrosarcoma of the larynx. PATIENTS AND METHODS: Results of CT studies, performed on 10 patients with pathologically proved chondrosarcoma of the larynx, were retrospectively reviewed and correlated with clinical presentation. RESULTS: In all patients, the mass was detected on CT. The most frequent site of origin of the tumor was the cricoid cartilage (nine cases) followed by the thyroid cartilage (one case). Coarse or stippled calcification within the tumor was the most helpful radiologic finding and was seen in every case. In eight patients, the tumor had both an endolaryngeal and an extralaryngeal growth pattern, whereas in two patients the tumor was entirely endolaryngeal. Hoarseness, dyspnea, and dysphagia were the most common symptoms. In all patients presenting with dyspnea, the tumor exhibited endolaryngeal components. In patients presenting with hoarseness, three tumors had endolaryngeal and extralaryngeal components and two tumors were entirely endolaryngeal. CONCLUSION: Cross-sectional imaging afforded excellent evaluation of the airway as well as the extralaryngeal component of the tumor.

Intracranial meningioma.

This case shows many of the imaging features classically associated with meningiomas. The illustrations show common location, shape, and local effects as well as enhancement characteristics. Hyperostosis and bone destruction, a fluid "cleft" surrounding the extraaxial mass, gray-white interface displacement, and secondary intraparenchymal changes are correlated with gross pathology findings. These key features are summarized in Table 1 and the composite anatomic diagram (Fig. 6).

Teaching skeletal radiology with use of computer-assisted instruction with interactive videodisc.

We evaluated the effectiveness and logistical practicality of use of a program consisting of computer-assisted instruction with interactive videodisc to teach residents in orthopaedic surgery the radiology of musculoskeletal injuries. Eleven residents (four in the fourth year of postgraduate training, five in the third year, one in the second year, and one whose level of training was not recorded) used the computer-videodisc program in a single session with no supervision. The residents took a pre-test and a post-test and also filled out a questionnaire on the efficacy and usefulness of this program compared with other educational materials. The eleven residents improved their scores from 56 +/- 8.6 per cent correct answers (mean and standard deviation) (range, 44 to 69 per cent correct answers) on the pre-test to 86 +/- 9.2 per cent correct answers (range, 69 to 100 per cent correct answers) on the post-test. All of the residents improved their scores, and the improvements were significant (p < 0.001; effect size, 3.57). The residents thought that the program increased their interest in the subject, and they preferred the computer-videodisc program to the use of actual radiographs, textbooks, videotapes, and slides and audiotapes for individual study. The residents reported no difficulty in using the program or the electronic equipment.

Mesenchymal chondrosarcoma of the cauda equina.

Primary central nervous system mesenchymal chondrosarcomas are extremely rare tumors composed of primitive mesenchymal cells punctuated by islands of cartilage in various stages of differentiation. Although there are isolated reports of tumors arising in the spinal dura, to our knowledge extraskeletal mesenchymal chondrosarcoma localized to the cauda equina has not been reported in the literature. We present an unusual case of a mesenchymal chondrosarcoma involving the nerve roots of the cauda equina. The clinical, pathological and neuroimaging features are reviewed and discussed.

Lesions of the cauda equina: a clinical and pathology review from the Armed Forces Institute of Pathology.

We reviewed the clinical records of 149 patients with pathologically proved cauda equina lesions in order to define the relative frequency and clinical presentations of the various diagnoses. The most common pathology was ependymomas (47 patients) followed in frequency by nerve sheath tumors (35 patients), metastases (27 patients), nonependymal glial neoplasms (six patients), meningiomas (six patients), lipomas (five patients), paragangliomas (five patients) and various other diagnoses (19 patients). Mean patient age at presentation for the various lesions included: metastases (51.5 years), nerve sheath tumors (49.7 years), nonependymal glial tumors (46.5 years), paragangliomas (41.2 years), ependymomas (38.3 years), meningiomas (34.7 years), and lipomas (18.4 years). ANOVA showed that the relationship between age and diagnosis for these groups to be statistically significant at a high level (P = 0.002). Low back pain was the most common symptom and occurred in 44 patients. Other symptoms included unilateral lower extremity pain or tenderness (24 patients), bilateral lower extremity pain or tenderness (16 patients), and bilateral lower extremity weakness (16 patients). No relationship between pathologic diagnosis and specific symptoms was found.

Botryomycosis ('bacterial ball') of the sinonasal tract caused by Pseudomonas aeruginosa.

BACKGROUND: Botryomycosis is a chronic bacterial infection that typically presents as a cutaneous lesion. Visceral involvement may occur, but mucosal disease is uncommon. We report two cases of sinonasal tract botryomycosis that clinically simulated a neoplasm. METHODS: Two cases of sinonasal tract botryomycosis were identified from the Otolaryngic Tumor Registry at the Armed Forces Institute of Pathology, Washington, DC. The clinical records, slides, and paraffin blocks were available for both cases. Histochemical stains, including Brown and Hopps, Gomori's methenamine-silver, acid-fast bacilli, mucicarmine, periodic acid-Schiff, and Warthin-Starry, were performed. RESULTS: The patients were an 81-year-old man and a 43-year-old woman. The man presented with acute ethmoiditis and a bulging eye. Radiographic studies showed a soft tissue mass in his left maxillary antrum with osseous erosion of adjacent anatomic sites. The woman presented with persistent headaches of more than 1 year's duration, with increasing severity in the months prior to presentation. An expansile soft tissue mass was identified in her right maxillary and ethmoid sinuses. Surgery was performed on both patients. The histology included amorphous, acellular material and separate, rounded eosinophilic granules associated with a neutrophilic infiltrate. A Splendore-Hoeppli phenomenon was seen. Filamentous gram-negative bacilli, identifiable only by histochemical staining, were morphologically compatible with Pseudomonas aeruginosa. Cultures of samples taken from both patients intraoperatively confirmed the organisms as P. aeruginosa. CONCLUSIONS: Sinonasal botryomycosis is a rare localized disease that may be mistaken clinically for an aggressive neoplasm. Complete surgical evacuation is curative.

The new WHO classification of brain tumors.

The current WHO classification greatly advances the ability to predict patient prognosis from pathologic diagnosis by introducing new tumor categories. This improved pathologic stratification is reflected in more accurate interpretations of diagnostic imaging studies. Pathology and oncology have progressed from a gross beginning, through microscopy and special stains, and into the realm of molecular biology and tumor genetics.