Come back next week to see the answer. In the meantime, check our social networks to leave your guesses!
Right-sided hypesthesias and sensorimotor aphasia
Subacute onset: the symptoms did not develop extremely quickly as we would expect in a stroke
Unremarkable past medical history (mild gastroesophageal reflux)
Non-contrast CT was ordered
An ill-defined hypodense lesion primarily located in the deep white matter of the left parietal lobe.
Glioblastoma (formerly known as glioblastoma multiforme/GBM).
Primary CNS lymphoma.
Demyelinating disorders (multiple sclerosis…).
A T2/FLAIR hyperintense lesion with enhancement was seen in the mentioned location and it was reported as representing either lymphoma or GBM in the conclusion of the MRI by the neuroradiologist.
![Imagen axial T2-weighted: [Describir hallazgos, ej. 'lesión hiperintensa en región X']](https://i0.wp.com/blog.myebr.org/wp-content/uploads/2025/04/Neuroradiology40_4.png?resize=240%2C300&ssl=1)
![Imagen axial T1-weighted post-contraste: [Describir realce o anatomía relevante]](https://i0.wp.com/blog.myebr.org/wp-content/uploads/2025/04/Neuroradiology40_5.png?resize=261%2C300&ssl=1)
The lesion has an incomplete rim of enhancement.
Glioblastoma: complete ring, irregular enhancement.
Primary CNS lymphoma: homogeneous enhancement. (In immunocompetent patients)
Demyelinating disease: incomplete ring enhancement.
M = Metastasis
A = Abscess
G = Glioblastoma (or other high-grade gliomas)
I = Infarct (subacute phase may show enhancement)/Infections (others – non-pyogenic pathogens: Mycobacteria, Toxoplasmosis, Cysticercosis, Cryptococcus)
C = Contusion and resolving hematomas
A = AIDS related: again, non-pyogenic infections (Cysticercosis, Cryptococcus)
L = Lymphoma
D = Demyelinating disease
R = Radiation necrosis
These lesions can closely resemble CNS tumors, and in such cases, they are referred to as tumefactive demyelinating lesions.
Another odd thing was overlooked.
We see concentric rings at the periphery of the lesion.
Alternating hyper- and hypo-intense bands. Resembling the layers of an onion bulb.
The patient was admitted to neurosurgery.
Thinking it was a tumor, the neurosurgeons resected most of the lesion.
The histological diagnosis was not consistent with GBM or lymphoma. It mentioned a focus of leukoencephalitis with fiber destruction.
While ad definitive diagnosis was not provided by the pathologists: it was presumed, however, that the lesion represented “some sort of demyelinating disease or MS”.
2 weeks after the initial MRI, before surgery (performed as part of pre-op MR tractography).
T1 GRE sag and ax, without contrast.
After surgery (2 days after the previous MRI).
T2WI sag and ax.
1 year after the first presentation, after surgery.
T2WI ax and FLAIR cube sag.
This is a case of Baló concentric sclerosis, a rare demyelinating disease, often considered a variant of multiple sclerosis (MS).
Unlike conventional MS, the clinical course of Baló’s sclerosis is typically monophasic, with more severe symptoms during a single episode of demyelination. Our patient has not developed additional focal neurological deficits or new lesions outside of the previously operated area.
The hallmark MRI findings are the “onion bulb” or “bullseye” appearance, most clearly seen on pre-contrast T1- and T2-weighted images. Similar to other demyelinating disease, contrast enhancement usually appears as an incomplete open ring. DWI might show diffusion restriction during the episode of active demyelination (representing in most part intramyelinic edema).
This case serves as a reminder thta, when faced with a complex diagnosis, it‘s important to pause,reflext and ask key questions.
Asking the right questions at the right time might help you to narrow the list of your differential diagnoses and rule out other possibilities.
In our case, if the possibility of tumefactive demyelination had been considered based on the pre-operative imaging, the extensive surgery could have been avoided.
The three most common tumor or tumor-like lesions of the corpus callosum are glioblastoma, primary CNS lymphoma and demyelinating disorders. Corpus callosum is composed of dense white matter tracts, that make it hard for hematogenous metastases to deposit in that area, so they are rarely seen in this region and not on the top of your differentials. The abundance of white matter tracts probably explains, however, why predominantly white matter diseases affect this region – namely glioblastoma and demyelinating diseases. CNS lymphoma has a predilection for periventricular regions, corpus callosum being one of those regions.
Enhancement can help in differentiating the three entities, with classically glioblastoma having irregular ring enhancement or heterogeneous enhancement, lymphoma having homogenous enhancement and demyelinating diseases having the open ring enhancement.
Knowing the epidemiology can also be helpful. Glioblastoma and CNS lymphoma are seen in slightly older/older patients (>40 years), with a slight male predominance. Tumefactive demyelinating lesions have, similar to other demyelinating disorders, a younger age of onset (<40 years) with a female predominance. Our patient was a female in her late teens.
With worsening paresis of cranial nerves CN3-7
Axial T2 image on the left shows partial obliteration of the right Meckel’s cave and an ill-defined T2 hypointense lesion on the right temporal fossa.
Axial T2 image on the right shows atrophy of the right-sided masticatory muscles.
Post-contrast 3D T1 FSE fat-saturated images showing an enhancing lesion overlying the right temporal fossa, with perineural spread along CN7, the auriculotemporal nerve and continuing intracranially via the right foramen ovale (note the asymmetry in enhancement).
3D bSSFP images (CISS) before (left) and after (right) contrast administration. bSSFP images contain both T1 and T2 information, therefore showing enhancement after contrast administration.
While pre-contrast image doesn’t depict any obvious pathology, the post-contrast image on the right clearly highlights tumor deposits (red arrows) along the lateral aspect of the right cavernous sinus. The tumor has encased the cranial nerves, leading to the patient’s symptoms. For comparison, the normal anatomy of the cranial nerves is shown on the left (green arrows).
This case shows a histologically verified squamous cell carcinoma of the temporal fossa spreading along the CN7, auriculotemporal nerve, mandibular nerve and into the right cavernous sinus.
Teaching points:
Multiple CN palsies of CN3-6 should raise a suspicion of cavernous sinus pathology.
Auriculotemporal nerve is an important connection between the facial and mandibular nerves.
bSSFP sequences like CISS contain both T1 and T2 information and therefore show post-contrast enhancement which can be diagnostically useful in conjunction to their excellent spatial resolution.
75-year-old patient:
Medical history:
* Previous left anterior descending artery (LAD) stenosis and iatrogenic left coronary artery (LCA) dissection.
* Underwent coronary artery bypass grafting (CABG) complicated by subsequent graft thrombosis.
* Stress myocardial perfusion imaging performed to assess myocardial ischemia/viability (first row stress perfusion imaging, second row dark blood late gadolinium enhancement imaging).
Subendocardial scar in LAD territory basal/midventricular with perfusion defect/inducible ischemia in LAD territory surpassing the area of infarction.
Stress myocardial perfusion depicts reversible ischemia in the LAD coronary artery territory anteroseptal/anterior (perfusion at rest not shown). Dark blood-LGE imaging depicts subendocardial scar in LAD territory especially basal, but smaller in extension than the inducible ischemia, indicating potential suitability of revascularization.
Standard dose of adenosine is 140 mcg/kg/min for at least 3 min.
– Patel, A, Salerno, M, Kwong, R. et al. Stress Cardiac Magnetic Resonance Myocardial Perfusion Imaging: JACC Review Topic of the Week. JACC. 2021 Oct, 78 (16) 1655–1668. https://doi.org/10.1016/j.jacc.2021.08.022.
– Shehata ML, Basha TA, Hayeri MR, Hartung D, Teytelboym OM, Vogel-Claussen J. MR myocardial perfusion imaging: insights on techniques, analysis, interpretation, and findings. Radiographics. 2014 Oct;34(6):1636-57. doi: 10.1148/rg.346140074. PMID: 25310421.
25-year-old female:
* On ultrasound, a large pelvic mass was found.
* CA-125: 24 U/ml
* Risk of ovarian malignancy algorithm (ROMA): 6.6%
* CT imaging was acquired.
Dermoid cyst/mature cystic teratoma
Fat content
Floating ball sign/pokemon ball sign
A fat-fluid level is present with a ball of debris in the center. Calcification can also be seen
80-year-old patient:
* Underwent aortic arch repair two years ago, now experiencing back pain
* Elevated levels of troponinin I (TNI) and D dimers
* Small pericardial effusion
Intramural hematoma type A.
Aortic intramural hematoma (IMH) is an atypical form of aortic dissection. It is considered part of the acute aortic syndrome spectrum, which also includes penetrating atherosclerotic ulcers and classical aortic dissection. The condition involves a contained hemorrhage within the aortic wall, which is best visualized on non-contrast CT scans. On contrast-enhanced imaging, a small ulcer-like projection (ULP) is observed, with an ascending aorta diameter of 53 mm. Risk factors for progression of intramural hematoma and worse prognosis include the presence of ULPs, IMH thickness greater than 10 mm, associated aortic aneurysm, and increase of the thickness of the intramural hematoma at follow-up CTA. Similar to aortic dissections, aortic intramural hematomas are categorized according to the Stanford classification system (type A: involves the ascending aorta, with or without descending aortic involvement, type B: confined to the descending aorta, distal to the origin of the left subclavian artery).The patient underwent emergency supracoronary ascending aortic replacement.
14-year-old patient:
– With left hip pain
– X-rays unremarkable
– MRI requested
Showing T2W Fat Sat images:
A CT
The MRI revealed a subchondral bone lesion in the superomedial region of the left femoral head, accompanied by noticeable and extensive bone edema in the surrounding area. There is also a minor effusion in the left hip joint.
Differential diagnosis includes either an osteochondral injury or, more likely, osteoid osteoma.
CT confirms the typical features of osteoid osteoma such as subchondral lucency within an internal sclerotic focus and the presence of sclerosis in the surrounding region
Reference: Bhure U et al: Osteoid osteoma: multimodality imaging with focus on hybrid imaging. Eur J Nucl Med Mol Imaging. 46(4):1019-36, 2019
66-year-old male:
– Presented with cough and dyspnea
– Known metastatic prostate cancer, under radiological surveillance
Progressive course with veiling basal lung opacities and right pleural effusion.
Widespread metastatic sclerosis of the examined chest wall and upper humeri, scapulae and clavicle.
Patient with right-sided iliac pain:
Appendicitis
Dehiscent left jugular bulb
Absence of the sigmoid plate that normally separates the jugular bulb from the middle ear cavity with a resultant bulging of the jugular bulb into the middle ear cavity
