From the radiologic pathology archives: mass lesions of the dura: beyond meningioma-radiologic-pathologic correlation.

Meningioma is the most common mass involving the dura, making it number one in the differential diagnosis for any dural-based mass; however, a variety of other neoplastic and nonneoplastic lesions also involve the dura. Knowledge of the dural anatomy can provide clues to the various processes that may involve this location. The neoplastic processes include both benign and malignant lesions such as hemangiopericytoma, lymphoma, solitary fibrous tumor, melanocytic lesions, Epstein-Barr virus-associated smooth muscle tumors, Rosai-Dorfman disease, and metastatic lesions. The nonneoplastic processes include infectious and inflammatory entities such as tuberculosis and sarcoid, which may mimic mass lesions. In some cases, neoplasms such as gliosarcoma may arise peripherally from the brain parenchyma, appearing dural-based and even inciting a dural tail. Many of these share similar computed tomographic, magnetic resonance imaging, and angiographic characteristics with meningiomas, such as a dural tail, increased vascularity, avid enhancement, and similar signal characteristics; however, knowledge of the patient's age, gender, and underlying conditions and certain imaging characteristics may provide valuable clues to recognizing these lesions. For example, in the population with human immunodeficiency virus infection, Epstein-Barr virus-associated smooth muscle tumors should be included in the differential diagnosis for dural-based lesions. The surgical course and prognosis for these lesions vary, and knowledge of the variety of lesions that involve the dura, their imaging appearances, and their clinical features assists in narrowing the radiologic differential diagnosis and optimizing patient treatment.

From the radiologic pathology archives: intraventricular neoplasms: radiologic-pathologic correlation.

A variety of neoplasms may arise in the ventricular system. Intraventricular neoplasms may be discovered as an incidental finding at cross-sectional imaging or may manifest with varied symptoms depending on their location, including symptoms of increased intracranial pressure. These lesions may arise from various ventricular structures, including the ependymal lining (eg, ependymoma), subependymal layer (eg, subependymoma), or choroid plexus (eg, choroid plexus neoplasms), or they may have a cell of origin that has yet to be determined (eg, chordoid glioma). Other neoplasms involving the ventricular system include central neurocytoma, subependymal giant cell tumor, meningioma, rosette-forming glioneuronal tumor, and metastases. The differential diagnosis for intraventricular neoplasms can be broad, and many of them have similar patterns of signal intensity and contrast enhancement at imaging. However, the location of the lesion in the ventricular system-along with knowledge of the patient's age, gender, and underlying conditions-will help narrow the differential diagnosis.

Magnetic resonance imaging of the fetal central nervous system, head, neck, and chest.

Magnetic resonance imaging (MRI) has become an important tool in the assessment of fetal anomalies. Although ultrasound remains the modality of choice for screening, MRI offers several advantages that permit optimal characterization of anomalies in certain situations. Accurate recognition and characterization of fetal anomalies guides decisions about pregnancy management and coordination of postnatal care. This article will briefly review safety and practical aspects of fetal MRI. We will then provide a concise summary of the most common indications for fetal MRI, and discuss the differential diagnosis and role of MRI in assessment of fetal brain, head, neck, spine, and chest anomalies.

Radiologic-pathologic correlation of pediatric and adolescent spinal neoplasms: Part 1, Intramedullary spinal neoplasms.

OBJECTIVE: The purpose of this article is to review the neuroimaging findings of pediatric and adolescent intramedullary spinal tumors in children. The differential diagnosis for lesions in this location is limited and can be further narrowed with knowledge of specific imaging characteristics. CONCLUSION: This article reviews the radiologic findings and differential diagnosis for intramedullary neoplasms. After completing this article, the reader should have an improved understanding of the types of neoplastic processes that can involve this region of the pediatric spine.

Radiologic-pathologic correlation of pediatric and adolescent spinal neoplasms: Part 2, Intradural extramedullary spinal neoplasms.

OBJECTIVE: The purpose of this article is to review the neuroimaging findings of intradural extramedullary spinal tumors in the pediatric and adolescent population. The differential diagnosis for lesions in this location is limited and can be further narrowed with knowledge of specific imaging characteristics. CONCLUSION: This article reviews the radiologic and pathologic findings of pediatric and adolescent intradural extramedullary neoplasms. After completing this article, the reader should have an improved understanding of the types of neoplastic processes that involve the extramedullary intradural compartment of the spine in the pediatric and adolescent age groups and should be able to narrow their differential diagnosis according to imaging findings.

From the archives of the AFIP: lesions of the pineal region: radiologic-pathologic correlation.

Lesions of the pineal region include a diverse group of entities. The most common neoplastic lesions are the germ cell tumors. Germ cell tumors may be hormonally active, and evaluation of serum or cerebrospinal fluid levels of oncoproteins assists in making the diagnosis. Neoplasms arising from the pineal parenchyma include the low-grade pineocytoma, pineal parenchymal tumor of intermediate differentiation, and the highly malignant pineoblastoma. Germ cell tumors and pineal parenchymal neoplasms do not have pathognomonic imaging findings, but imaging in combination with laboratory evaluation helps narrow the differential diagnosis. Neoplasms may also arise from the variety of cell types residing in the proximity of the pineal gland. These include lipomas, meningiomas, and astrocytomas. Congenital lesions such as epidermoid and dermoid cysts and lipomas can also occur. Knowledge of the variety of lesions that occur in the pineal region, their imaging appearances, and their clinical features assists in narrowing the radiologic differential diagnosis and optimizing patient treatment.

Imaging evaluation of demyelinating processes of the central nervous system.

Demyelinating processes involving the central nervous system have a variety of aetiologies and can be separated into primary and secondary demyelinating processes. The classic example of primary demyelination is multiple sclerosis. Secondary demyelination, where the aetiology is known, includes infectious, metabolic and toxic disease processes. The underlying component of all demyelinating disorders is damage to the myelin sheath and/or the oligodendrocyte, the cell forming the myelin sheath. These processes often have similar imaging findings, making knowledge of the patient's history, physical examination and laboratory evaluation imperative for developing a differential diagnosis. This pictorial essay provides a review of the imaging of these diverse disorders.

Pigmented lesions of the central nervous system: radiologic-pathologic correlation.

Pigmented lesions of the central nervous system (CNS) are a diverse group of entities that run the gamut from benign to malignant. These lesions may be well circumscribed or diffuse, and their imaging appearances are influenced by the degree of melanin content as well as the presence or absence of hemorrhage. Pigmented lesions include primary melanocytic lesions of the CNS and metastatic melanoma, as well as other CNS neoplasms that may undergo melanization, including schwannoma, medulloblastoma, and some gliomas. Primary melanocytic lesions of the CNS arise from melanocytes located within the leptomeninges, and this group includes diffuse melanocytosis and meningeal melanomatosis (seen in neurocutaneous melanosis), melanocytoma, and malignant melanoma. Primary melanin-containing lesions of the CNS must be differentiated from metastatic melanoma because these lesions require different patient workup and therapy. Absence of a known primary malignant melanoma helps in the differential diagnosis, but an occult primary lesion outside the CNS must be sought and excluded. Pigmented lesions of the CNS are uncommon, and knowledge of their imaging characteristics and pathologic features is essential for their identification.