A forum dedicated to the expansion in neuropathology knowledge for students and practitioners alike.
Meningiomas, like the one pictured here, typically show whorling architectural pattern and nuclear pseduoinclusions. The vast majority of meningiomas are low grade (WHO Grade 1) dura-based tumors with good prognosis following complete resection. However, recent studies have suggested that endothelial cell hypertrophy and/or microvascular proliferation in an otherwise typical meningioma are correlated with shorter progression free... Continue Reading →
Pilocytic Astrocytoma (PA) characteristically exhibits biphasic morphology featuring densely fibrillar, compact regions alternating with loosely-cohesive microcystic or myxoid areas; the latter is pictured here. Diagnosis can be difficult, especially on small biopsies, but molecular testing can help. BRAF-KIAA1549 fusion occurs in about 70% of PAs, whereas BRAF V600E mutation occurs in about 5-10% of PAs.
Pilocytic astrocytoma is a circumscribed glioma (WHO Grade I) commonly found in children and young adults. Characteristic features include piloid cells with long, thin, hair-like cytoplasmic processes and a myxoid background, which are both seen here in this medium power image of a cytologic smear preparation performed during intraoperative consultation.
The vast majority of meningiomas are benign grade I tumors. Meningiomas can be upgraded to grade II, called atypical meningiomas, if they show increased mitotic activity (4 or more mitoses in 10 high power fields) or other worrisome histopathologic features, such as tumor cells exhibiting a prominent and large nucleolus. Notice the mitosis in the center-right of the image and... Continue Reading →
Astrocytes are star-shaped glial cells that comprise a large proportion of brain tissue. Non-neoplastic reactive astrocytes can sometimes be difficult to differentiate from the neoplastic astrocytes of glial tumors called astrocytomas. This GFAP stain highlights the key morphologic differences between the star-shaped and widely spread-out non-neoplastic reactive astrocytes compared to the neoplastic astrocytes in this glioblastoma, which exhibit crowding and severe variation in... Continue Reading →
Many blood vessels that supply the brain and spinal cord initially run within the covering layers on the external surface, called the leptomeninges (also known as the pia-arachnoid), before plunging into the deeper neural tissue. As the vessel transitions from the outer layers into deeper tissue, the perivascular space immediately surrounding the vessel, called Virchow-Robin space, may provide a conduit for infectious/inflammatory processes. ... Continue Reading →
The spinal cord is covered by protective outer connective tissue layers called the pia-arachnoid or leptomeninges. Inflammatory or infectious processes that involve the leptomeninges, called leptomeningitis, can also involve the adjacent spinal nerve roots, which similarly have an outer covering of connective tissue that is continuous with the leptomeninges. The image depicts a spinal cord with acute... Continue Reading →
Life-sustaining blood is supplied to the brain by blood vessels, many of which run within the arachnoid layer covering the external surface before plunging into the deeper brain tissue. If the vessels are disturbed, either by trauma, infection, or other insults, blood may exit the vessel and collect in the subarachnoid space in a process called subarachnoid... Continue Reading →
Neurofibrillary tangles, like the one shown here, are composed of hyperphosphorylated tau proteins. Intracellular neurofibrillary tangles and extracellular amyloid plaques comprise the two characteristic neuropathologic findings of Alzheimer Disease, the most common neurodegenerative disease associated with progressive memory loss. This image was taken from an area of the brain that is often affected in Alzheimer Disease: the hippocampus, which is a... Continue Reading →
Epidermoid cysts (pictured here with surrounding brain tissue) are histologically characterized by a thin layer of squamous epithelium similar to the epidermal lining the skin. However, unlike skin (which sheds its outer layer of dead cells into the environment), the keratin debris of the sloughed-off upper layer of the epidermoid cyst build up within the cyst center resulting in... Continue Reading →
Adventures in Neuropathology 