Abdominal #19

A 79-year-old female patient:
– Presented with abdominal pain, nausea, vomiting
– Previous history of cholecystitis and pancreatitis
– Laboratory findings:
*Elevated C-reactive protein and white blood cell levels

What do you see?

Pneumobilia (arrow)

Cholecystoduodenal fistula (red arrow)
Gastric (blue arrow) and duodenal (green arrow) distension

Gallstone located in the proximal jejunal segment (red arrows)
Gastric distension (blue arrows)

What is your diagnosis?

Gallstone ileus

Abdominal CT images obtained two years earlier show that the gallstone is in the gallbladder (arrows).

Teaching points:

* Gallstone ileus is a cause of mechanical small bowel obstruction that generally affects the elderly and has high mortality. It is a rare complication of chronic cholecystitis. It develops when a gallstone passes through a cholecystoenteric fistula leading to small bowel obstruction.

* Gallstones most commonly become impacted in the distal ileum.

* The classical imaging findings on abdominal radiographs form Rigler triad: pneumobilia, small bowel obstruction, and ectopic radio-opaque gallstone

* CT is the most frequently used imaging modality for the diagnosis as it demonstrates the rim-calcified or total-calcified ectopic gallstone, abnormal gallbladder with air collection, presence of air-fluid level, biliary-enteric fistula, and transition point of small bowel obstruction. However, only a minority of gallstones are calcified. Therefore, they may be overlooked in intestinal lumen, which may result in misdiagnosis. Multiplanar reformatted CT images can be helpful to locate the migration site of the ectopic stones.

* Treatment: Surgery with removal of gallbladder stone is the definitive treatment.

In our case, the patient underwent surgery. Enterotomy with gallstone removal was performed. According to the operation note, the gallstone was located in the jejunum 20 cm distal to the ligament of Treitz.

Musculoskeletal #31

8-year-old patient:

– With a chronically painful right knee and ankle

Clinical information:

– Patient with no relevant clinical history
– Parents mention a difficulty when running, the patient trips very easily and sometimes struggles to use the right leg. The right leg is often painful

Showing the X-ray right knee and the pelvis

What do you see?

X-ray right knee

Eccentric, lytic bone lesions with sharp margins
No periosteal reaction
Ground-glass matrix of the lesion in the right tibial diaphysis
Soap-bubbly appearance of the lesion in the femoral diaphysis

X-ray pelvis

Expansile bone lesion with ground glass matrix in the right femoral neck, extending into the proximal diaphysis
Slight varus deformity of the femoral neck
Similar lesion in the right iliac wing/acetabular region

A CT was performed:

Showing X-ray of both feet.

What do you see?

Expansile bone lesion with ground glass matrix involving the 1st metatarsal and proximal and distal phalanges of the left foot
Soap-bubbly lesions of the talus and 5th metatarsal

What is your diagnosis?

Imaging findings:

– Multiple bone lesions with benign appearance
– Expansile lesion with ground-glass matrix in the femoral neck virtually pathognomonic for fibrous dysplasia
– Genetic testing could not reveal mutations of the GNAS gene: no syndromic association in this patient

Teaching points

Teaching points:

Benign bone lesions
– Usually central in bone
– Varying degrees of expansion
– Ground-glass matrix (mildly sclerotic)
– Lack of aggressive features (no periosteal reaction, no cortical breakthrough or soft tissue mass)
Aetiology: developmental dysplasia
Fibrous dysplasia is polyostotic in 15–20%, often in syndromic association (mutations of the GNAS gene)
– McCune-Albright syndrome (in combination with endocrine dysfunctions)
– Mazabraud syndrome

Musculoskeletal #30

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

Left knee X-ray:


What is the most likely diagnosis?


* 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?


* Pathological fracture
* Malignant transformation into chondrosarcoma

Differential diagnosis includes..

Differential diagnosis

* Bone infarct
* Chondrosarcoma
* Intraosseous ganglion


* 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

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?

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


– Always consider in older patients
– Multiplicity and known primary

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



– 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


– 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

– 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


– 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

– 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)


– 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

Key signs:
“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


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:




– 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 #5

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.

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

Musculoskeletal #11

68-year-old male:
* Presents with a mass around knee which has been present for seven years and has been enlarging since then

What do you see?

A sclerotic ill-defined soft tissue mass around the knee was present on radiographs.
The mass is located in the soft tissue around the knee with no apparent bone destruction.

Coronal fat-suppressed T2 WI (a) shows a hyperintense lobulated mass which was hypointense on T1 WI (b) and has peripheral heterogeneous enhancement on postcontrast T1 WI (c); cortical bone is preserved.

The mass encircles a pedunculated lesion which continues with cortical and medullary bone (arrows), consistent with an osteochondroma.
Histopathologic diagnosis of the mass is chondrosarcoma.


* Osteochondromas are developmental lesions rather than true neoplasms and are often referred to as an osteocartilaginous exostosis (or simply exostosis).
* An osteochondroma is composed of cortical and medullary bone protruding from and continuous with the underlying bone; cortical and medullary continuity between the osteochondroma and parent bone is well depicted on MRI.
* Malignant transformation, almost invariably due to chondrosarcoma arising in the cartilage cap of the lesion, occurs in approximately 1% of solitary osteochondromas.
* Lesions that grow or cause pain after skeletal maturity should be suspected of malignant transformation since osteochondromas only rarely enlarge after this time.

Abdominal #8 – Long case

76-year-old male.
* Presents with acute abdominal pain, enlarged abdomen and no defaecation since a few days.

What do you see?

Abdominal CT scan shows dilated colon loops with a calibre change in the sigmoid. Whirl of mesenterial vessels.

Differential diagnosis is Sigmoid volvulus. This was confirmed on OR.

Sigmoid volvulus is differentiated from a cecal volvulus by its ahaustral wall and the lower end pointing to the pelvis.

Abdominal radiographs will show a large, dilated loop of the colon, often with a few gas-fluid levels. Specific signs include coffee bean sign and absent rectal gas.

CT scan will show large gas-filled loop lacking haustra, forming a closed-loop obstruction. Specific signs include:
– whirl sign: twisting of the mesentery and mesenteric vessels
– bird’s beak sign: if rectal contrast has been administered
– X-marks-the-spot sign: crossing loops of bowel at the site of the transition
– split wall sign: mesenteric fat seen indenting or invaginating the wall of the bowel

Rectal tube insertion for treatment is successful in treating 90% of cases. Occasionally patients suffer from recurrent sigmoid volvulus, for which a surgeon may consider sigmoid colopexy (surgical fixation of the sigmoid colon), or in the surgically unfit, a percutaneous endoscopic colostomy (PEC) might be performed. The mortality rate of sigmoid volvulus is 20-25%. The most serious complication is bowel ischemia, not blow-out perforation as you might expect.

Abdominal #2 – Long case

We present the case of a 31-year-old woman with:
* Nausea and vomiting since three days
* Unable to eat or drink without vomiting
* Epigastric pain after eating
* Feels weak

* No prior trauma or illness
* No fever, no diarreha, no hematemesis or bloody stools
* No other family members ill

See below the laboratory findings:

What do you think?

Click here to see the answer

Signs of dehydration with secondary acute renal impairment and electrolyte disorders

Abdominals X-Ray were performed:

What do you see on the X-Rays?

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Apparent elevation of the right hemidiaphragm with obscuration of the right cardiac border

Air – fluid level at the right upper quadrant: free air?
Absense of gastric air and fluid-air level
Colonic air at the right upper quadrant (Chilaiditi)

Apparent soft tissue mass at the right upper quadrant

Elongated right liver lobe (Riedel lobe)
Instability of the symphysis pubis


* Apparent elevation of the right hemidiaphragm with obscuration of the right cardiac border
* Air – fluid level at the right upper quadrant: free air?
* Colonic air at the right upper quadrant (Chilaiditi)
* Apparent soft tissue mass at the right upper quadrant

* No apparent dilated bowel loops
* Elongated right liver lobe (Riedel lobe)
* Instability of the symphysis pubis

Differential diagnosis of a large amount of air in the RUQ

* Pneumoperitoneum
* Subphrenic abscess
* Hepatic abscess
* Anterior interposition of colon to the liver

* Loculated pneumothorax (mimick)
* Situs inversus – gastric air (mimick)
* Pneumobilia, portal venous gas (smaller amount)

Images from an abdominal CT-scan:

What do you see on the CT images?

Click here to see the answer
Anterior defect in the right hemidiaphragm

Partial herniation of stomach (blue arrow) and transverse colon (green arrow)

Gastric outlet obstruction due to compression of the pyloric region (red arrow),with secundary dilatation with fluid (blue arrows)

Normal position of the gastro-esophageal junction and hiatus

Collapse of the right middle lobe (green arrow) and partial collapse of the right lower lobe (blue arrow).


* Anterior defect in the right hemidiaphragm
* Partial herniation of stomach and transverse colon
* Gastric outlet obstruction due to compression of the pyloric region of the stomach, with secundary dilatation with fluid
* Normal position of the gastro-esophageal junction and hiatus
* No signs of ischemia
* Collapse of the right middle lobe and partial collapse of the right lower lobe.

What is the most likely diagnosis?

Click here to see the answer

Morgagni hernia of the diaphragm

Patient had a laparoscopic reduction of the hernia with mesh closure of the defect. No signs of ischemia at surgery.
Uneventful recovery with resolution of pain and normal intake the day after.

Morgagni hernia

* Rare congenital diaphragmatic hernia (<5% of all CDH)
* Anterior (retrosternal)
* Right-sided (90%)
* Usually small
* +/- 30% symptomatic: respiratory distress (newborn), recurrent chest infections, abdominal symptoms
* Contents: omental fat, transverse colon (60%), stomach (12%)

* Treatment: surgical repair
> In symptomatic cases, some say also in asymptomatic cases: prevention of strangulation of hernia contents
*Prognosis: good

* Differential diagnosis:
> Traumatic diaphragmatic rupture
> Diaphragmatic eventration / weakness / paralysis (abnormal contour / position of the dome)
> Cardiophrenic angle lesions ( pericardial fat pad, cyst, lipomatosis, tumor)

Emergency #11 – Long case

23-year-old male:
* Macroscopic hematuria and blood at urine meatus

What is the most likely diagnosis? What should we do next?

Click here to see the answer

 X-ray: Bilateral pelvis fractures discontinuity iliopectineal line most clearly left-sided

CT: Bilateral ramus superior/anterior iliac bone and ramus inferior pubic bone
Avulsion fracture symphysis pubis
Fracture sacrum on the right

Look also in soft-tissue setting!

Large hematoma posterior of symphysis pubis around urethra and perineum, lateral around the pelvic floor obturator internus muscles and cranially in the retroperitoneal Retzius space anterior of the bladder

Do a RUG: Retrograde Urethrogram. If intact, followed by CT Cystography

RUG shows contrast extravasation and complete rupture of anterior bulbous part of urethra, grade V isolated anterior injury. However, the rupture might be at the anatomic weak point, the bulbomembranous junction, meaning avulsion of the puboprostatic ligament and stretching of the membranous urethra. There is no contrast above the urogenital diaphragm (level of symphysis pubis). Contrast in the bladder is a residue from the IV contrast given for earlier total body CT.

Goldman classification urethral injury

Anterior urethra = Penile and bulbous part
Posterior urethra = Membranous and prostatic part

  • Type I: stretching the posterior urethra due to disruption of puboprostatic ligaments and hematoma, but urethra is intact
  • Type II: posterior urethral injury above urogenital diaphragm (between ischiopubic rami)
  • Type III: injury to membranous urethra, extending into the proximal bulbous urethra (i.e. with laceration of the urogenital diaphragm), thus contrast extravasation below diaphragm
  • Type IV: bladder base injury involving bladder neck and proximal urethrainternal sphincter is injured, hence the potential for incontinence
  • Type IVa: bladder base injury, not involving bladder neck (cannot be differentiated from type IV radiologically)
  • Type V: anterior urethral injury (isolated)

* In this case, no CT cystography was performed
* Patient was treated conservatively