Alice Boyd Smith

From the Archives of the AFIP : Central Nervous System Infections Associated with Human Immunodeficiency Virus Infection: Radiologic-Pathologic Correlation

Diseases of the central nervous system (CNS) in patients infected with the human immunodeficiency virus (HIV) result directly from HIV itself or from a variety of opportunistic agents. These infections include progressive multifocal leukoencephalopathy, toxoplasmosis, and cryptococcosis. A resurgence of tuberculosis and neurosyphilis has also been documented. Mass lesions, meningoencephalitis, demyelination, atrophy, and vascular lesions are the commonly encountered imaging findings. The introduction of highly active antiretroviral therapy (HAART) has improved both the clinical and radiologic findings in HIV-infected patients and reduced the number of opportunistic infections. In countries that use HAART, AIDS (acquired immunodeficiency syndrome) dementia complex is becoming the most common neurologic complication of HIV infection, whereas opportunistic infections are still the major cause of neurologic complications in patients from countries that do not commonly use HAART. Immune reconstitution inflammatory syndrome, which occurs in some patients in the weeks to months after the institution of HAART, may alter the typical imaging appearance of infectious diseases involving the CNS. Knowledge of the spectrum of imaging findings of these infectious diseases, as well as the effect that treatment has on imaging appearances, is important in the evaluation of HIV-infected patients.

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.

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.

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 patients age, gender, and underlying conditions-will help narrow the differential diagnosis.

Immune reconstitution inflammatory syndrome of the brain: case illustrations of a challenging entity.

Immune reconstitution inflammatory syndrome represents a spectrum of clinicopathologic entities encountered in human immunodeficiency virus-infected patients who have received highly active anti-retroviral therapy. The diagnosis is often challenging, treatment options are limited, and the prognosis is variable. To increase awareness and define the clinicopathologic features, we present our experience with 6 probable cases involving the brain, including 1 autopsy. Clinicopathologic review was supplemented by immunohistochemical analysis. There were 5 men and 1 woman, ranging in age from 34 to 47 (mean, 41; SD, 5.39) years. All patients experienced neurologic deterioration (focal deficits in 5/6) after highly active anti-retroviral therapy. All specimens showed a predominance of CD8+ lymphocytic inflammation. Concurrent CNS infections included human immunodeficiency virus encephalitis, progressive multifocal leukoencephalopathy, cryptococcal meningitis, and syphilis. One patient died, 1 was lost to follow-up, 2 improved, and 2 showed no substantial clinical changes. Subtle and overlapping features may preclude a definitive diagnosis. To capture all suspected cases, it is important to consider the possibility of this entity. In this study, the degree of CD8+ inflammation was more pronounced in the single fatal example, and mast cells were not identified in the infiltrates. Although nonspecific, imaging findings may offer clues to early diagnosis.

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 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 patients 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.

Aus den Archiven für Radiologische Pathologie – Tumoren der Dura: zur Differenzialdiagnose des Meningeoms – Korrelation zwischen radiologischen und pathologischen Befunden

Der haufigste Tumor mit Durabeteiligung ist das Meningeom; bei der differenzialdiagnostischen Abklarung aller durabasierten Tumoren steht es daher immer an erster Stelle. Es gibt jedoch eine ganze Reihe anderer neoplastischer und nicht neoplastischer Lasionen, an denen die Dura ebenfalls beteiligt ist. Aus der Kenntnis der Anatomie der Dura lassen sich Hinweise auf die verschiedenen Prozesse gewinnen, die sich an dieser Lokalisation abspielen konnen. Bei den neoplastischen Prozessen handelt es sich teils um benigne, teils um maligne Lasionen: Hamangioperizytome, Lymphome, solitare fibrose Tumoren, melanozytare Lasionen, Epstein-Barr-Virus-assoziierte Tumoren der glatten Muskulatur, Manifestationen der Rosai-Dorfman-Krankheit und Metastasen. Als nicht neoplastische Prozesse sind infektiose und entzundliche Entitaten, wie Tuberkulose und Sarkoidose, zu nennen, die Tumoren sehr ahnlich sein konnen. In manchen Fallen entwickeln sich Neoplasien, wie z. B. Gliosarkome, an der Peripherie des Hirnparenchyms, sodass der Anschein erweckt wird, sie gingen von der Dura aus und hatten sogar einen Duraauslaufer (sog. Dural Tail). Viele dieser Lasionen weisen in der bildgebenden Darstellung mittels CT, MRT und Angiografie Gemeinsamkeiten mit den Meningeomen auf, z. B. einen Dural Tail, eine vermehrte Gefasversorgung, prompte Kontrastmittelanreicherung und Ahnlichkeiten der Signalcharakteristika. Alter, Geschlecht und Grundkrankheiten des Patienten sowie bestimmte Besonderheiten im Bildgebungsbefund ermoglichen jedoch wichtige Ruckschlusse auf die Art der Lasionen. So sollte beispielsweise bei der Differenzialdiagnose durabasierter Lasionen bei HIV-infizierten Personen (Personen mit Infektion durch das humane Immundefizienzvirus) auch an die Epstein-Barr-Virus-assoziierten Tumoren der glatten Muskulatur gedacht werden. Das chirurgische Vorgehen bei den einzelnen Lasionen ist verschieden und ebenso die Prognose. Die Kenntnis der unterschiedlichen Lasionen, die die Dura betreffen, ihrer Bildgebungsbefunde und ihrer klinischen Merkmale hilft bei der Eingrenzung der radiologischen Differenzialdiagnose und bei der Optimierung der Therapie.

Aus den Archiven der Radiologischen Pathologie

Das System der Hirnventrikel ist Ursprungsort verschiedener Neoplasmen. Diese werden in vielen Fallen als Zufallsbefunde bei Querschnittsuntersuchungen mittels bildgebender Verfahren entdeckt, konnen sich aber auch, je nach ihrer Lokalisation, durch Beschwerden, wie z. B. Hirndrucksymptome, bemerkbar machen. Die Lasionen konnen von verschiedenen ventrikularen Strukturen ausgehen: dem Ependym, das die Ventrikel auskleidet (Ependymome), der subependymalen Schicht (Subependymome) oder dem Adergeflecht (Plexustumoren); es gibt aber auch Tumoren (z. B. die chordoiden Gliome), deren Ursprungszellen noch unbekannt sind. Weitere das Ventrikelsystem betreffende Neoplasmen sind zentrale Neurozytome, subependymale Riesenzelltumoren, Meningeome, rosettenbildende glioneuronale Tumoren sowie Metastasen. Differenzialdiagnostisch kommt bei einem intraventrikularen Neoplasma ein breites Spektrum verschiedener Tumoren in Betracht, und viele davon weisen im Bildgebungsbefund Ahnlichkeiten hinsichtlich Signalintensitat und Kontrastverstarkung auf. Jedoch erleichtert die Kenntnis der Tumorlokalisation im Ventrikelsystem – zusammen mit Alter, Geschlecht und Grunderkrankungen der betroffenen Patienten – die differenzialdiagnostische Abklarung.