December 2010

Patrick Farley, MD (Neuroradiology Fellow) andThomas Bouldin, MD (Neuropathologist)

Clinical Neuroradiology–Neuropathology Conference

CLINICAL HISTORY: 59-year-old man with history of altered mental status and hearing loss.

Case #1

Differential diagnosis Infectious Meningitis

Neoplastic Meningitis

Breast, lung most common extracranial sources

Most common primary brain tumors are GBM, medulloblastoma, pineal tumors, and choroid plexus tumors

Neurosarcoidosis

Lacy leptomeningeal enhancement

May have ventricular or dural-based enhancing masses

Brain biopsy revealed a poorly differentiated neoplasm within the leptomeninges and around several intracortical blood vessels. The immunophenotype of the neoplastic cells was consistent with a melanoma. The histologic features do not permit distinction between metastatic melanoma (common) and primary leptomeningeal melanoma (rare).

Case #2

CLINICAL HISTORY: 21-year-old postpartum woman with a sellar mass.

Adenoma

Pituitary hyperplasia

25–50% of females 18–35 years old have upwardly convex pituitary

Usually < 10 mm unless pregnant, lactating

Aneurysm

Usually eccentric, not directly suprasellar

Pituitary gland visible and identified as separate from mass

Flow-related artifacts on MRI are common

Meningioma

Pituitary gland may be visible and identified as SEPARATE from mass

Differential Diagnosis (continued) Metastasis

Lymphocytic hypophysitis

Can mimic adenoma clinically and on imaging studies

May show zones of very low T2 signal peripherally

Most common in peripartum female

Craniopharyngioma

Ca++, cysts more common, Children > adults

Rim/nodular > solid enhancement

May be indistinguishable from Rathke cleft cyst

Biopsy revealed a dense lymphoplasmacytic infiltrate within the anterior pituitary. The gland also showed interstitial fibrosis and a loss of secretory cells. The remaining secretory cells form the clusters of larger, more eosinophilic cells in the photomicrograph.

Lymphocytic hypophysitis Females > males, with a ratio of approximately 5:1

Often during last months of pregnancy or first few months postpartum

Often have family history of autoimmune disease

Sometimes associated with Hashimoto’s thyroiditis or Graves’ disease

No adverse effect on fetus

Presents as hypopituitarism and/or mass effect—headache or visual field cuts

If unrecognized, may cause death from panhypopituitarism

Treatment includes hormonal replacement and surgery to reduce mass effect.

Diagnostic signs:

Thick non-tapered stalk, with or without pituitary mass

Supra, intrasellar mass

Areas of low T2 signal peripherally or/and in cavernous sinuses

Usually < 10 mm but may be up to 2-3 cm

Rounded pituitary gland with infundibulum that appears thickened, nontapering, or bulbous

Lymphocytic hypophysitis

CLINICAL HISTORY: 73-year-old female with acute headache and right-sided weakness.

CASE #3

Differential Diagnosis Hypertensive hemorrhage

Deep structures (basal ganglia, thalami, cerebellum) but may also occur in cortex and subcortical white matter

Hemorrhagic infarct

Hemorrhagic metastases

Cerebral amyloid angiopathy

Beta Amyloid IHC

Postmortem examination of the brain in this case revealed numerous cortical and leptomeningeal vessels infiltrated by amorphous, eosinophilic amyloid. Inset shows the immunohistochemical staining of the amorphous material for beta amyloid.

Cerebral amyloid angiopathy (CAA) Deposition of beta amyloid in cortical and leptomeningeal vessels

Common in older patients

Often associated with Alzheimer’s disease

Complications of CAA include intracerebral lobar hemorrhage, microbleeds, subarachnoid hemorrhage, cerebral infarcts, inflammatory CAA, and white-matter abnormalities.

CAA Imaging Look for:

Lobar hemorrhage(s) of different ages

Multifocal areas of susceptibility artifacts corresponding to chronic microbleeds, particularly in cortex

Hemorrhage may extend to subarachnoid space or into ventricles

Acute lobar hemorrhage tends to be large

Protocol advice:

Recommend T2*-weighted sequence in all patients > 60 years of age

CLINICAL HISTORY: 65-year-old man with history of renal cell carcinoma first diagnosed in 1994. He has since had numerous surgeries for metastases to the brain. He also had stereotactic radiosurgery for an olfactory groove-based lesion, which was presumed to be a meningioma.

Case #4

CLINICAL HISTORY (continued): A few months later the presumed meningioma developed surrounding edema, became larger, and demonstrated areas of different enhancement intensity and T2 signal.

Case #4

Biopsy of the olfactory-groove lesion revealed a meningioma (right half of photomicrograph). Also present within the meningioma was a focus of metastatic renal cell carcinoma (left half of photomicrograph).

Tumor-to-tumor metastasis Metastasis of a systemic cancer to an intracranial tumor is rare.

Most often, the CNS tumor is a meningioma. Other reported types of intracranial tumors harboring a metastasis include 8th-nerve schwannoma, glioma, hemangioblastoma, and pituitary adenoma.

Breast and lung are the most common primary sites, with breast being the most common site.

Renal cell carcinoma metastatic to a meningioma has been reported only rarely. Renal cell carcinoma may also metastasize to a hemangioblastoma in the context of the von Hippel-Lindau syndrome.

Lanotte M, et al. Systemic cancer metastasis in a meningioma: Report of two cases and review of the literature. Clinical Neurology and Neurosurgery 111 (2009) 87–93.

CLINICAL HISTORY: 2-year-old African-American girl with left eye strabismus for 9 months.

Case #5

Differential Diagnosis Retinoblastoma

Calcifications, enhancement, mass of low T2 signal intensity

Persistent hyperplastic primary vitreous

Coat’s disease

Retinal astrocytoma

Rare; isolated or in association with tuberous sclerosis (TSC)

Ocular toxocariasis

PHPV Congenital

Due to incomplete regression of embryonic ocular blood supply

Imaging

Best diagnostic clue: Hyperdense or hyperintense small globe, retrolental soft tissue, no Ca++

Retinal detachment common

Central linear structure: Cloquet’s canal

Layering blood or debris may be present

PHPV is the most common intraocular abnormality to be confused with retinoblastoma

The intraocular lesion is a small blue cell tumor with neuroblastic (Homer Wright) rosettes (arrows). The histological features of the tumor are typical of a retinoblastoma.

RetinoblastomaCT:

Calcified intraocular mass

Unilateral in 70-75%

MR: T2 Hypointense relative to vitreous

Moderate to marked heterogeneous enhancement

Best for assessing extraocular and intracranial disease