Aunt Mickeys

Aunt Mickey (They Look the Same until You Undress Them). Internal Capsule Infarct or Something Else?

This 30 year old hypertensive female smoker presented with acute onset of right hemiparesis. Her history also included OCP use and dyslipidemia. MRI demonstrated an acute infarct in the posterior limb of the left internal capsule. ADC maps showed corresponding low ADC values. MR angiography, echocardiography, and lower extremity venous ultrasound were all normal.

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Seven months later the patient re-presented to the ED with persistent waxing and waning hemiparesis, peripheral loss of sensation, and worsening ataxia. MRI at this admission demonstrated resolution of diffusion abnormalities in the left internal capsule but new right hemispheric lesions. The more inferior lesion was associated with restrained diffusion. The bright signal on DWI in the more superior lesion was due to “T2 shine-through”.

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FLAIR imaging at the second presentation demonstrated multiple white matter lesions.

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There was prominent “ring” enhancement on of the uppermost right hemispheric white matter lesion.

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Subsequent clinical evaluation supported a diagnosis of multiple sclerosis.

Discussion:

Lesions of multiple sclerosis may demonstrate diffusion restraint. This does not reliably correlate with acute inflammation and blood brain barrier breakdown, as illustrated by the enhancing lesion with increased ADC in this case. The presenting lesion location and clinical background in this patient led (unsurprisingly) to a diagnosis of lacunar infarction. Her young age (30) might have been a clue to suggest an alternate diagnosis.

References:

1. Karaarslan E, Arslan A. Diffusion weighted MR imaging in non-infarct lesions of the brain. EJR 2007;65:402-16

2. Stadnik TW, Demaerel P, Luypaert RR, et al. Imaging tutorial: Differential diagnosis of bright lesions on diffusion-weighted MR images. Radiographics 2003;23:e7…

Aunt Mickey (They Look the Same until You Undress Them). Nerve Sheath Tumor or Something Else?

Aunt Mickeys are alternative diagnoses for “Aunt Minnies”. They represent less common diagnoses, and emphasize the importance of clinical history and careful imaging review.

Dumbell spinal mass: Nerve sheath tumor or something completely different?

A  “dumbell” spinal mass was discovered during CT angiographic evaluation of an aortic aneurysm in this 66-year-old female. She had experienced constant but stable low back pain. There were no neurologic deficits.

NECT at T11-12
Non-contrast axial CT at T11-12
CECT at T11-12
Contrast-enhanced axial CT image at T11-12
Axial T2 weighted image at T11-12
Axial T2 weighted image at T11-12
Axial T1 weighted image at T11-12
Axial T1 weighted image at T11-12
Axial enhanced T1 weighted image at T11-12
Axial enhanced T1 weighted image at T11-12

The lesion was biopsied under CT guidance. At pathology, the lesion was composed of closely apposed small to medium sized blood vessels (some of which contained organizing thrombus) without intervening stroma. The vessels were admixed with fibroadipose tissue. The pathological diagnosis was “hemangioma” (a misnomer, as these lesions represent venous vascular malformations, not true hemangiomas). More detailed review of the imaging study revealed several findings that might have suggested this pathologic possibility.

Axial NECT demonstrates a tiny phlebolith (arrow).
Axial NECT demonstrates a tiny phlebolith (arrow).
Bone window demonstrates honeycomb changes and thickened trabeulae (arrow).
Bone window demonstrates honeycomb changes and thickened trabeulae (arrow) in the right transverse process.

Aunt Mickey (They Look the Same until You Undress Them). Colloid Cyst or Something Else?

Aunt Mickeys are alternative diagnoses for “Aunt Minnies”. They represent less common diagnoses, and emphasize the importance of clinical history.
Fig 1.
FIg. 1 T1 weighted midline sagittal image.
Fig 2.
Fig 2 Axial T2-weighted at third ventricular level.

This submission is a 23 year old male patient who became lethargic and somnolent after playing soccer. On physical exam he was somnolent, but arousable with no focal neurologic deficits. An unenhanced CT of the brain initially demonstrated right frontal horn dilatation. A subsequent CT demonstrated bilateral lateral and third ventricular dilatation. Following placement of a ventriculostomy catheter, MRI was obtained and demonstrated a cystic-appearing third ventricular lesion. The lesion was hyperintense on T1WI (Fig 1) and hypointense on T2WI (Fig 2).

During attempted endocscopic removal of the lesion, it was “lost” from the surgical forceps, though a partial specimen was retrieved. Subsequent MR imaging demonstrated that the cyst was now located in the ventricular trigone (Fig 3). At pathology, findings were consistent with a cysticercal cyst. There was no scolex in the specimen.

Fig 3
Fig 3. Axial T1 weighted MR image at level of ventricular atria.
frontal-horn
Fig 4. Axial CT at level of the frontal horn. Arrow indicates presumed initial cyst location.
Fig 5. Arrow indicates a right parietal parenchymal calcification.
Fig 5. Arrow indicates a right parietal parenchymal calcification.

Interestingly, review of the preoperative CT studies suggested that the cyst had started in the right frontal horn  (Fig 4) and also  revealed a parenchymal calcification (Fig 5), almost certainly an additional manifestation of cysticercosis in this Hispanic patient. Key “hints” to correct identification of this Aunt Mickey case included the parenchymal calcification, cyst mobility, and ethnicity of the patient.

Colloid cysts are the most common lesion of the anterior superior third ventricle. They are of variable signal intensity on T1 and T2 weighted images, presumably reflecting the variable viscosity of proteinaceous cyst contents. …