Musculoskeletal #30

38-year-old with left knee pain.
Showing multiple images:

Left knee X-ray:

STIR:

What is the most likely diagnosis?

Enchondroma

* Relatively common intramedullary cartilage neoplasms with benign imaging features
* Constitute ~5% (range 3–10%) of all bone tumors and ~17.5% (range 12–24%) of benign bone tumors

What are the radiological features?

Radiological features

* Narrow zone of transition
* Sharply defined margins
* Chondroid calcification, however, purely lytic in the hands/feet
* Sometimes expansile – more commonly in hands/feet
* Mild endosteal scalloping
* Do not “grow” through cortex (unless pathologic fracture)
* No bone destruction
* No periosteal reaction
* No soft tissue mass

What may be the complications?

Complications

* Pathological fracture
* Malignant transformation into chondrosarcoma

Differential diagnosis includes..

Differential diagnosis

* Bone infarct
* Chondrosarcoma
* Intraosseous ganglion

References

* Murphey MD, Flemming DJ, Boyea SR et-al. Enchondroma versus chondrosarcoma in the appendicular skeleton: differentiating features. Radiographics. 18 (5): 1213-37. Radiographics (abstract) – Pubmed citation
* Walden MJ, Murphey MD, Vidal JA. Incidental enchondromas of the knee. AJR Am J Roentgenol. 2008;190 (6): 1611-5. doi:10.2214/AJR.07.2796 – Pubmed citation
* Douis H, Saifuddin A. The imaging of cartilaginous bone tumours. I. Benign lesions. Skeletal Radiol. 2012;41 (10): 1195-212. doi:10.1007/s00256-012-1427-0 – Pubmed citation
* Mulligan ME. How to Diagnose Enchondroma, Bone Infarct, and Chondrosarcoma. (2019) Current problems in diagnostic radiology. 48 (3): 262-273. doi:10.1067/j.cpradiol.2018.04.002 – Pubmed

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)

Head and neck #7

60-year-old female:
– Since a few weeks eye movement disorder and diplopia of the left eye, tinnitus, and sinusitis.
– Non-enhanced CT of the orbits is performed (due to contrast allergy).

What are your findings?

Widened infraorbital canal left eye with thickening of the infraorbital nerve.

What is your differential diagnosis and do you want more imaging?

Yes, we want MRI to sort things out more.

Findings: Smoothly thickened T2 hyperintense, enhancing infraorbital nerve in its canal. No continuation posteriorly to the vidian canal or anteriorly to the pre-antral region. No pathologic paranasal sinus mass or pharyngeal mucosal mass indicating perineural tumor spread.

Differential diagnosis:
Schwannoma.
Less likely malignant cause like perineural tumour spread.

Biopsy is performed of right lacrimal gland, since clinically this was found to be prominent (radiologically slight asymmetry, slightly higher T2 signal).

Histopathology: IgG4 disease or dacryoadenitis.

After this, whole body scanning showed evidence of IgG4 disease in the pancreas also. Patient was treated with steroids.

Follow-up MRI: Decrease in size of the infraorbital nerve from 11 to 5 mm. Still high T2 signal, however, the decrease in size on steroids suggests other diagnosis than schwannoma, in this case probably involved in orbital IgG4 disease. Rare!

Emergency #35

61-year-old female:
– Trauma
– Fracture? What do you see?

Showing the supine AP and lateral view, due to the inability to stand on the right leg.

Click here to see the answer

Diagnosis: Lipohemarthrosis (fat-blood level) indicating intra-articular #
Comminutive though non-displaced tibia plateau fracture Avulsion fracture proximal fibula (Segond fracture – 100% association with ACL injury)
CT: Schatzker type VI

Schatzker tibia plateau classification

Schatzker I: wedge-shaped pure cleavage fracture of the lateral tibial plateau, having less than 4 mm of depression or displacement
Schatzker II: splitting and depression of the lateral tibial plateau; namely, type I fracture with a depressed component
Schatzker III: pure depression of the lateral tibial plateau; divided into two subtypes:
Schatzker IIIa: with lateral depression
Schatzker IIIb: with central depression
Schatzker IV:  medial tibial plateau fracture with a split or depressed component
Schatzker V: wedge fracture of both lateral and medial tibial plateau
Schatzker VI: transverse tibial metadiaphyseal fracture, along with any type of tibial plateau fracture (metaphyseal-diaphyseal discontinuity)

Neuroradiology #34

54-year-old woman:
– Known breast cancer
– Arm paresis and soft-tissue lump

What are the salient findings?

Left: NECT, bone algorithm. Aggressive-like bone lesion with permeative pattern and hair on end periosteal reaction

Right: MRI T1 post-Gd. Associated trans-diploic soft-tissue mass with extracranial and intracranial-extraaxial components. Solid, homogeneous and avidly enhancing. Contiguous dural thickening and enhancement.

What is the differential diagnosis?
DIFFERENTIAL DIAGNOSIS FOR TRANS-DIPLOIC SKULL VAULT LESION WITH AGGRESSIVE-LIKE BONE AFFECTATION

1- Metastasis
2 – Myeloma/Plasmocytoma
3 – Lymphoma
4 – Primary Bone Tumour (Osteosarcoma)
5 – Dural Lesion (Meningioma+++, Hemangiopericytoma)

METASTASES
METASTASES

– Always consider in older patients
– Multiplicity and known primary

Imaging
Varies depending on tumor type and aggressiveness

– Lytic: Most tumor types
– Permeative: Highly cellular and small-round cell tumors (PNET, small cell lung, lymphoma)
– Sclerotic/mixed: Prostate, breast. Less frequently: Transitional cell, neuroendocrine, PNET
– Hypervascular: Renal cell, melanoma, thyroid, hepatocarcinoma, lung, neuroendocrine

Possible soft-tissue components

LYTIC AGGRESSIVE BONE LESION/S IN PATIENT >40 years old. METASTASES vs MYELOMA

MULTIPLE MYELOMA (MM)/SOLITARY PLASMOCYTOMA
MULTIPLE MYELOMA (MM)/SOLITARY PLASMOCYTOMA

– Affects older patients (median 68-70 years). Very rare under 40 years (<10%) Imaging
MM 4 patterns of bone involvement
– Diffuse lytic bone infiltration simulating osteopenia
– Multiple focal lytic well-defined lesions
– Solitary plasmacytoma
– Sclerotic bone lesions (exclusively associated with POEMS sd)

Solitary plasmacytoma in the skull: lytic, aggressive trans-diploic, soft tissues, and hypervascular aspect

CLASSIC APPEARANCE OF MM
CLASSIC APPEARANCE OF SOLITARY PLASMOCYTOMA OF THE SKULL
LYMPHOMA
LYMPHOMA

– 7% of all bone malignancy; 5% of extranodal lymphoma
– All ages; predominates in adults (peak 50-60 years); men/women 1.5:1
– Secondary dissemination >>> primary bone lymphoma
– Imaging characteristics of a hypercellular small round cell tumour

Imaging
– Trans-diploic permeative bone pattern and abundant of tissue components (small round blue cells spread through Haversian canals conditioning a striking relatively little bone destruction in comparison to important soft-tissue lesions)
Hyperdensity on NECT, T2 hypodensity and striking diffusion restriction on DWI (all signs related to hypercellularity)
– Homogenous enhancement
– No or little necrosis

CHARACTERISTIC IMAGING FINDINGS FOR LYMPHOMA
OSTEOSARCOMA
OSTEOSARCOMA

– Most common primary high-grade bone sarcoma
– Bimodal distribution: 10-14 and >40 years old
Extremely rare in the skull in adults, and much more frequently arising from coexisting Paget’s disease> >previously irradiated bone> or bone infarction
– Clinically, quickly growing painful mass

Imaging
– Destructive, aggressive lesion, with periosteal reaction, soft tissue-mixed lytic-blastic component. May show “fluffy”, “cloud-like” osteoid matrix.

Secondary osteosarcoma arising in a Pagetic skull. See the globally aggressive pattern and the deep hypointensities inside the soft-tissue components probably transducing osteoid matrix (usually easily depicted on CT, non-available in this case)

MENINGIOMA
MENINGIOMA

– Most common brain tumor (36% of all brain tumors)
– Predilection for middle-aged females
– Can produce neurologic symptoms due to compression
– Most do not infiltrate bone, but when they do it, the hyperostosis is very specific, virtually pathognomonic
– Intra-diploic or trans-diploic meningiomas are less frequent

Imaging
Key signs:
Calcifications
“Dural tail” and extra-axial semiology
Hyperostosis (very specific)
– Hypervascular with intense homogenous enhancement

*Even the great specificity of the hyperostosis, bone involvement can be VERY VARIABLE including aggressive-like lysis and periosteal reactions that do not exclude or go against the diagnostic

Ddx: Hemangiopericytoma (Solitary Fibrous Tumor New WHO 2016 classification). Younger, frequently male patients. Osteolysis possible, but NO hyperostosis. NO calcifications. The rest of imaging features identical to meningioma, differentiation is very difficult and challenging

EXAMPLES OF THE MULTIPLE FACES OF MENINGIOMAS AND THEIR BONE INVOLVEMENT. REMEMBER, POLYMORPHISM IS AN IMPORTANT FEATURE OF THIS ENTITY

With all the information mentioned above:

Could meningiomas condition aggress periosteal reaction? Does it go against its diagnosis

Meningiomas are very frequent, specially in middle-aged woman, if all or the vast majority of features favour this diagnosis, a relatively atypical bone affectation (lysis, periosteal reaction instead of the virtually pathognomonic hyperostosis) may not change the diagnostic orientation.

Bonus clues and some advance imaging pearls

Diffusion: Striking restriction in lymphomas
Perfusion: Striking high rCBV in meningiomas
Spectroscopy: Alanine (and GLX) in meningiomas. Striking high Cho in lymphoma and plasmacytoma. Striking high lipids in metastases

Back to the case:

ARE THE ADVANCED IMAGING TECHNIQUES HELPFUL?

FINAL DIAGNOSIS: MENINGIOMA (WHO GRADE 2)

TAKE HOME MESSAGE REGARDING MENINGIOMA

– Very frequent, specially middle-aged women
– Important to know the classic characteristic features, some of them are very specific; but recognize the great polymorphism/many faces of this entity
– Advanced imaging can be helpful
– Not all the lesions in a neoplastic patient are metastases

Head and Neck #6

– 66-year-old female:
– Feels a lump in the neck when swallowing

In what space houses this lesion?

Mass in the right parapharyngeal space or deep part of parotid space. No parapharyngeal fat is visible, so either the lesion displaces the fat or it arises from it. It is certainly not from the carotid space, since the carotid arteries are displaced posteriorly. It is also not from the mucosal space since it compresses the lateral oropharyngeal wall, instead of arising from it.

Do you want further imaging to make a diagnosis and what?

MRI will provide you more details in head and neck lesions where the lesion arises from exactly, and what the origin is. MRI is made with T1, T2, and T1 with Gad and fat suppression.

What is your differential diagnosis?

Origin from deep parotid lobe, so DD benign or malignant salivary gland tumor, such as pleiomorphic adenoma, adenoid cystic of mucoepidermoid cell carcinoma. Radiologists are not good in differentiating benign from malignant lesions on MRI. Histopathology has to be done. DWI will help you a little, in that, malignant lesions have often lower ADC values, but also Wharthin tumors do so. DD rare schwannoma arises from V3 (mandibular nerve) in the true parapharyngeal space.

Solution

We performed ultrasound and cytologic punction. This turned out to be a fairly rare acinic cell carcinoma.

Teaching point: Malignant tumors of the salivary glands are well delineated and do not have to present as ill-defined lesions, nor have to have lymph node metastasis or perineural spread.

Emergency #32

53-year-old male:
– Hemodialysis patient
– Presents with a very large scrotum, size of a football
– Patient is not sick, no fever
– Laboratory results are normal
– US: Incarcerated inguinal hernia? Hydrocele? Malignancy?

What is the most likely diagnosis?

Diagnosis: Extensive scrotal lymphoedema

– Extensive scrotal wall thickening associated with diffuse lymphoedema extending to the base of penis not involving the penile corpora
– No extension into the deep subcutaneous tissue planes, inguinal canal, or muscles
– No extension to the groin or lower abdomen
– No inguinal adenopathy
– Both testicles are morphologically normal with no associated hydroceles
– There is no associated soft-tissue mass

Neuroradiology #30

A 6-year-old boy presenting to emergency department with headache, nausea, and vomiting

What do you see?

Intra-axial cystic lesion with mass effect shows CSF signal intensity on all sequences, without enhancement and perilesional edema

Differential diagnosis include

* Parasitic diseases (hydatid cyst) spheric
* Neuroglial cyst may have surrounding gliosis
* Porencephalic cyst surrounding gliosis, communicates with ventricle

Same cystic lesion in superior lobe of left lung

What is the most likely diagnosis?

Hydatid cyst disease
Both lesions were treated by surgery