Musculoskeletal #27

53-year-old female:

– Chronic sensory polyneuropathy (autoimmune). Long-term corticosteroid therapy.
Forefoot pain for three weeks (acute onset without trauma).
– Physical examination: no haematoma , mild swelling.
X-ray performed on day 2 after initial pain.
MRI performed on day 25 after initial pain.

What are the findings?

X-Ray: No obvious fracture.

MRI:
– Bone marrow heterogeneous oedema within the third metatarsal diaphysis (hypointense on T1W image, hyperintense on Proton Density (PD) FatSat image).
Linear low signal intensity fracture identified in all sequences.
Periosteal reaction due to callus formation. Periosteal thickening and enhancement (contrast administration is not necessary for diagnosis).
– Surrounding soft-tissue oedema (adjacent fat and interosseous muscles).

Metatarsal stress fracture (“march fracture”)

– Stress fractures are caused by overuse and repetitive activity.
– Everyday activities may result in a stress fracture if there is any disease or therapy that weakens the bone such as osteoporosis or long-term use of steroids (bone insufficiency: long-term treatment with steroids in this case).
– Classically affects the 2nd or 3rd metatarsal of the foot “march fracture”: named after its prevalence in soldiers who often undertake repeated and prolonged periods of walking as part of their training or work.
– Bone changes are usually not evident on X-rays before 10 to 21 days following the injury. May not be visible for several weeks later, until callus bone formation (the sensitivity range, for detecting stress fractures on initial examinations, is 15-35%; it increases to 30-70% at follow-up studies due to bone reaction).

MRI findings:
– The fluid-sensitive sequences (T2-weighted images with chemically selective fat suppression or STIR sequences) are very useful for the detection of the earliest changes of stress reaction, such as periosteal reaction, muscle, or bone marrow oedema.
– T1-weighted sequences depict the anatomy and more advanced stress-related findings.

Grading based on MRI (Arendt and Griffiths)🙂
1: Mild – moderate periosteal oedema on STIR, no marrow changes.
2: Moderate – severe periosteal oedema on STIR + marrow changes on T2-weighted.
3: Grade 2+ marrow changes on T1-weighted.
4: Fracture line visible.

Head and Neck #12

24-year-old male:
– Feels a lump in the upper lateral corner of right eye.
– MRI was made.

What do you see?

Preseptal lesion right supero-lateral corner, lateral to lacrimal gland.
T2 and T1 hyperintense, low signal after fat suppression.
No enhancement (right upper picture).
Slight remodeling of bone.
No invasive growth no post-septal component.

What is the most likely diagnosis?

Diagnosis: dermoid cyst, also fits with age and location of lesion.

Head and Neck #11

43-year-old female:
– Known with M. Ollier (multiple enchondromas)
– Long-standing headache
– Recent ophthalmoplegia right side
– MRI was made

What is the most likely diagnosis?

Large, lobulated T2 hyperintese mass centered in the petrous apex, off-midline.
More specific: on the petroclival synchondrosis (bonus point!).
Extension in clivus, sphenoid bone, and cavernous sinus and extracranial to the neck trhough hypoglossal canal and jugular foramen. Not extending to or from the internal acoustic canal.
Very high T2 signal with some T2 hypointense serpiginous lines, possible flow voids or calcifications.
Isointense on T1, intense enhancing after contrast.

Do you need additional CT?

CT shows central arc and ring calcifications in the lesion, suggesting chondromatous origin. Bony margins are lytic, not well-defined margins. Non-sclerotic margins. No hyperostosis.

Differential Diagnosis

– Intraosseous extension and pattern atypical for most common CPA lesions meningioma and schwannoma (of 12th hypoglossal nerve considering mass in this canal also)
– Does not fit with cholesterol granuloma (sclerotic margins)
– High T2 signal does not fit lymphoma or plasmacytoma
– Growth into foramina does not fit metastasis and unknown with primary tumor
– No mucosal space origin (so no nasophayryngeal carcinoma)
– Could be a jugular paraganglioma but, however, not centred at jugular foramen, and no flow voids on additional MRA TOF
– Age and location and also history of M. Ollier, could fit well with chondrosarcoma

Bonus points for those who see the mass multicystic lesion low in the neck on the left with trachea deviation. Unfortunately, no further imaging was done in this hospital. This could be a lot of things, including extensive multinodular struma, lymphangioma, neurofibroma, or paraganglioma.

Emergency #38

51-year-old female:

– Known with hypertension.
– Presents with hemiballism right.

What do you see?

Infarct? Other pathology?

Click here to see the answer

– Unilateral hyperdense caudate nucleus, globus pallidus, and putamen
– Dx: Non-ketotic hyperglycemic hemichorea
– Key message: Basal Ganglia are a known site for metabolic- and toxic-related pathology, as is the diffuse cortical grey matter
– Key message: Usually bilateral changes in BG indicate toxic or metabolic pathology, but do not forget this in your differential diagnosis if you only see unilateral pathology!
– This woman was not known with diabetes, but the radiologist suggested it

Head and Neck #9

47-year-old male:
– Headache since 2 months, nausea, and vomiting.
– Papilledema but no loss of vision.
– MRI is made.

What is the most likely diagnosis?

Expansive mass in the midline centered in the clivus (basiocciput and basisphenoid) with high signal on FLAIR (upper left), intermediate to low T1 signal, high T2 signal, and moderate heterogeneous enhancement after contrast administration.

No diffusion restriction.
ADC value is around 1350. No dural tail.
No encasement of basilar artery.
Compression on pons but no invasive growth.
Upward displacement of chaism, anterior displacement of pituitary gland and stalk.

Diagnosis: chordoma.

Does not fit with meningioma, pituitary macroadenoma, chondrosarcoma, lymphoma, or plasmacytoma.This
was histologically proven.

Head and neck #8

Where is the lesion?

Left carotid sheath posterior to the carotid bulb, internal, and external carotid arteries.

How does it look like?

Large oval avidly enhancing lesion displacing the carotid bifurcation anteriorly.

What is the differential diagnosis?

Carotid bulb paraganglioma: avidly enhancing lesion with characteristic splaying of the internal and external carotid arteries (lyre sign).
Glomus vagale: paragangliomas but of the vagus nerve, located posterior to the carotid arteries displacing them anteriorly.
Vagal schwannoma: those that arises within the carotid sheath posteriorly but usually shows moderate enhancement compared with the avid enhancement of the paragangliomas.

What is the most likely diagnosis

Glomus vagale

Emergency #36

47-year-old female:

– Found EMV 3 after assault

What do you see?

Click here to see the answer

– Diagnosis: Diffuse subdural hematomas of multiple ages (convexities, parafalcine, tentorium) But more important:

Diffuse swelling of gyri and edema with effacement of the CSF-containing spaces
– Diffuse loss of normal grey-white differentiation
– Decreased bilateral basal ganglia attenuation

– = Sequelae of traumatic brain injury (TBI) indicating hypoxic-ischemic injury, with poor prognostic outcome. Patient died several hours later

– Note: We do not see here the reversal sign (reversal of the normal CT attenuation of grey and white matter) or white cerebellum sign (diffuse oedema and hypoattenuation of the cerebral hemispheres with sparing of the cerebellum and brainstem, resulting in apparent high attenuation of the cerebellum and brainstem relative to the cerebral hemispheres)