Primary Meningeal Pheochromocytoma: A Case Report

Pheochromocytoma is a rare endocrine tumor arising from the chromaffin tissue, and it is able to produce and secrete catecholamines. Lymph nodes, liver, lung and bone are the most frequent sites of metastasis. We report here on a case of pheochromocytoma arising from the dura in a patient who was surgically treated for bilateral pheochromocytoma five years previously.

Cystic Solitary Fibrous Tumor Arising From the Left Occipital Meninges: A Case Report

Solitary fibrous tumor (SFT) is a benign mesenchymal neoplasm of a spindle-cell origin, and it usually involves the pleura. It's occurrence in various organs of the body has recently been described. Meningeal SFT is very rare. Radiologically, it is a strongly enhancing solid mass and is undistinguishable from fibrous meningioma and hemangiopericytoma. Yet we report here on a case of SFT with massive cystic degeneration that arose from the meninges of the left occipital region.

Clear-Cell Meningioma: CT and MR Imaging Findings in Two Cases Involving the Spinal Canal and Cerebellopontine Angle

Clear-cell meningioma is a rare subtype of meningioma which occurs at a younger age and has a higher recurrence rate than other subtypes. We report two cases of clear-cell meningioma, one in the thoracolumbar spinal canal and the other in the cerebellopontine angle. Though the CT and MR imaging findings were not different from those of ordinary meningioma, after surgical removal the condition recurred repeatedly in the patient with spinal canal involvement.

Primary Leptomeningeal Malignant Melanoma in Posterior Fossa and Upper Cervical Canal: A Case Report

The term 'primary melanocytic neoplasm' covers a wide disease spectrum, from well differentiated meningeal melanocytoma to malignant melanoma, its most aggressive malignant counterpart. Previous reports have shown that due to the paramagnetic effect of melanin, melanocytic neoplasms show high signal intensity on T1-weighted images and very low signal intensity on T2-weighted images, with relatively homogeneous contrast enhancement. The differentiation of leptomeningeal malignant melanoma from benign melanocytoma is important because of their different prognosis but on the basis of imaging findings alone is difficult. Ultrastructural immunohistochemical analysis is a possible alternative. We report the imaging findings of rare primary malignant melanoma, revealed by noncontrast-enhanced CT as a high-density mass, and demonstrating high signal intensity on T1-weighted images, and very low signal intensity on T2WI, with relatively good contrast enhancement.

Evaluation of Preoperative Embolization of Meningioma

PURPOSE: To evaluate the efficacy and safety of preoperative embolization of intrancranial meningioma. MATERIALS AND METHODS: We retrospectively reviewed intrancranial meningioma patients (n=37) who underwentpreoperative embolization. They were categorized into two groups, skull base lesions (n=22) and non-skull baselesions (n=15), according to tumor location. In addition, embolization results were classified by comparisonbetween pre- and post-embolization angiography as complete (residual tumor staining or= 10 or 30%). In each group, estimated blood loss (EBL) was estimated by amount ofintraoperative transfusion with pre- and post-operative hemoglobin level. Tumor resectability was evaluated byfollow-up computed tomography. New symptoms occurring within 24 hours of embolization were considered to be thoseassociated with embolization ; symptoms improved by conservative treatment were regarded as mild, while thoseresulting in new deficits were considered severe. RESULT: In the group with skull base lesions (n=22), completeembolization with the criteria of residual tumor staining of less than 30% was performed in 14 patients(EBL=1770ml;complete surgical removal in nine patients and incomplete removal four). Incomplete embolization wasperformed in eight patients (EBL=3210ml; complete and incomplete removal each in four patients). In the group withnon-skull base lesions, complete embolization with the criteria of residual tumor staining of less than 10% wasperformed in five patients (EBL=970ml) and incomplete embolization in ten (EBL=2260ml). Complete tumor removal waspossible in this group regardless of the completeness of preoperative tumor embolization. In a case ofintraventricular meningioma (3%), intratumoral hemorrage occurred on the day following embolization. Other mildpost-embolization complications occurred in three cases (8%). CONCLUSION: Preoperative embolization can be aneffective and safe procedure for meningioma and may reduce intraoperative blood loss. Its effectiveness may dependon tumor location and the degree of embolization, though the procedure seems to be helpful for lseions at theskull base.

MR Findings of Atypical Meningioma: Comparison with Benign Meningioma

PURPOSE: Atypical meningioma is an intermediate type, between benign and malignant meningiomas, and has ahigher recurrence rate and poorer prognosis than the benign type. The purpose of this study was to evaluate thedifferential imaging findings between atypical and benign meningiomas. MATERIALS AND METHODS: Over a five-yearperiod, 11 acses of atypical meningioma (in ten patients) were pathologically proven, and 30 benign meningiomaswere collected consecutively over 6 months. In retrospective analysis, the MR findings of atypical and benignmeningiomas were compared with respect to tumor respect to tumor margin, lobulation, intra-/peritumoralhemorrhage, cystic change, heterogeneity peritumoral edema, enhacement of adjacent meninges, invasion of adjacentvenous sinus and adjacent bony change. RESULTS: Significant differential MR findings between the two groups wereill-defined tumor margin(atypical-27%;benign-0%), lobulation(82%;43%), heterogeneity(73%;30%), and peritumoraledema(100%;47%). With regard to moderate edema, there was no significant difference between the twogroups(36%;23%), and with regard to intra-/peritumoral hemorrhage, cystic change, enhancement of adjacentmeninges, invasion of adjacent venous sinus, and adjacent bony change, MR findings between the two groups were notsignificantly different. CONCLUSION: The MR findings of atypical meningioma are significantly different inseveral ways from those of benign meningioma, and these differences may help differentiate the two types.

CT and MR Findings of Meningioangiomatosis

PURPOSE: To characterize the CT and MR findings in patients with meningioangiomatosis(MA). MATERIALS AND METHODS: Four patients (18 to 53 years old, two females and two males) with MA were retrospectively reviewed. CTwas used in four cases and MR in three. Pathologic specimens were obtained from all four. RESULT: All lesions were located in the cortical and subcortical areas and showed spotty(n=1), popcornlike(n=2), or gyral(n=1) calcification. The mass were associated with surrounding edema and gliosis. In two patients, lesions were multiple and were accompanied by eccentric cysts. CONCLUSION: MA is a surgically correctable benign disease. Its radiologic characteristics are cortical or subcortical mass with various calcifications, associated peripheral edema and gliosis.