Musculoskeletal #18 – Flashcard

27-year-old patient with neurofibromatosis-type 1 (NF-1). Bone lesions found on PET-CT

What are the imaging findings?

Multiple bilateral multiloculated eccentric metaphyseal lucent lesions with thin sclerotic rim

What is the most likely diagnosis?

Multiple non-ossifying fibromas in a patient with NF-1

Teaching points

Very common benign lesion in young adults. Tend to heal or involute. Vast majority asymptomatic. Large lesions may be painful or weaken the cortical predisposing to pathological fracture (rare). Multiple in NF-1

Cáceres’ Corner Case 256 – SOLVED

Dear Friends,

welcome to the second trimester of 2021! Showing today PA chest radiograph of a 66-year-old man with chest pain without any other symptoms.

What do you see?
More images will be shown on Tuesday and Wednesday.

Dear friends, showing today the lateral chest view.
Does it help?

Today I am showing an enhanced axial CT.
What would be your diagnosis?

Click here to see the answer

Findings: PA chest radiograph shows an increase in size and opacity of the left hilum
(A, arrow), due to superimposition of a well-defined posterior mass visible in the lateral view (B, arrow). At first glance, the appearance of the mass is compatible with an extrapulmonary lesion. However, there is retrocardiac nodule in the PA view (A, red arrow), suggesting a metastasis from an intrapulmonary mass.

Enhanced axial CT confirms an irregular pulmonary mass (C, arrow), which is invading the chest wall, as confirmed by the displaced intercostal artery (C, yellow arrow) and erosion of the underlying rib (D, circle).

Caudal slices confirm the retrocardiac nodule (E, white arrow) and additional nodules (E-F, red arrows) representing pleural implants.
Biopsy of the main mass returned as lung carcinoma.

Final diagnosis: Carcinoma of the lung simulating an enlarged hilum in the PA view.
 
Congratulations to Dr LeLam and thaf1212, who detected the retrocardiac nodule, which is the clue to determine that the main mass is intrapulmonary.
 
Teaching point: Remember that one of the three causes of unilateral enlarged hilum is superposition of a pulmonary opacity either in front or behind the hilum (the other two are enlarged hilar lymph nodes and increase in size of the pulmonary artery)

Neuroradiology #26 – Long case

Where is the abnormality?

Right temporal lobe

What is it like?

Effacement of the temporal horn of the right lateral ventricle and subtle hypodensity within the right temporal lobe

What would you do next?

CT with contrast and MRI

Click here to see more images

What are the MRI signal characteristics?

High-signal intensity lesion on FLAIR with significant edema and mass effect. Ring enhancement on post-contrast images

Dr. Pepe’s Diploma Casebook 170 – SOLVED

Dear Friends,

This week’s case follows the pattern of a “Meet the Examiner” presentation, with questions and answers similar to a real examination. Take your time before scrolling down for the answer.

There will be no new blog posts over the Easter period. The next case will be published on Monday, April 5, 2021.

The images belong to a 65-year-old woman with cough and low-grade fever. The referred physician demanded a chest CT.

What would be your diagnosis?

1. Pneumonia
2. Pulmonary infarction
3. Peripheral adenocarcinoma
4. Any of the above

Click here to see the answer

Findings: unenhanced axial and sagittal CTs show LLL airspace disease with a surrounding halo (B-C arrows). In my opinion, the sensible answer is 4. Any of the above, although I liked adenocarcinoma because of the peripheral halo and air bubbles within the infiltrate (A, circle).

Click here to see more images

Patient was diagnosed of pneumonia and treated with antibiotics, without improvement. Chest radiographs taken 13 days later shows progression of the LLL opacity (A and B, arrows).

A CT was recommended.

Click here to see the CT images

Two axial and one sagittal views are selected. What would your diagnosis be:

1. Peripheral adenocarcinoma
2. Tuberculosis
3. Covid pneumonia
4. None of the above

Click here to see the answer

In comparison with the previous CT, the LLL infiltrate has increased markedly in less than two weeks. An upper halo persists (A and C, arrows). A small infiltrate has appeared at the right lung base (B, arrow) In my opinion, this rapid progression rules out carcinoma and TB. A PCR was negative. Blood tests were not remarkable. It was considered that the patient had an unusual pneumonia, and the antibiotic was changed.

Click here to see more images

The fever disappeared with the new antibiotic and the patient improved moderately. A new CT was taken three weeks later. What would your diagnosis be?

1. Löffler syndrome
2. Goodpasture syndrome
3. Cryptogenic organizing pneumonia
4. Any of the above

Click here to see the answer

Findings: The most striking finding is the disappearance of the LLL infiltrate and the apparition of two new areas of airspace disease in RLL and LLL (A, arrows). There is a halo sign in the LUL infiltrate (B, arrows) and a negative halo in the RLL infiltrate (B and C, arrows).
This change of location of the opacities falls in the category of migratory infiltrates which are caused by several diseases, some of them listed in the previous questions.

The patient had no risk factors for parasitic infection and no peripheral eosinophilia, ruling out Löffler syndrome. Renal function was not altered, excluding Goodpasture’s syndrome

The combination of migratory infiltrates and a negative halo sign was very suggestive of a cryptogenetic organizing pneumonia, that was confirmed with BAL and an excellent response to corticosteroid treatment.

Final diagnosis: cryptogenic organizing pneumonia

Organizing pneumonia (OP) is a clinical, radiological and histological entity usually associated to other pathologies. The idiopathic form of OP is called cryptogenic organizing pneumonia (COP).
Clinical manifestations of COP begin with a mild flu-like illness with fever, cough and malaise.
In chest imaging it may appear as localized airspace opacity that may be confused with ordinary pneumonia, adenocarcinoma or aspiration, among others. The lack of response to antibiotic treatment and the peripheral location may help in suggesting the diagnosis.

I am presenting this case because it shows two features the help in the diagnosis: migratory infiltrates and the reverse halo sign.
Migratory infiltrates are not unique to COP, but they occur in a limited number of diseases (Loeffler syndrome, vasculitis, etc.) and their presence in the adequate clinical setting should suggest COP.
The reverse halo was originally described as specific of COP, but since then it has been seen in many other entities. It is defined as a central ground-glass opacity  surrounded by denser consolidation of crescentic shape or a complete ring. It is visible in about 20% of cases.

In this patient the combination of both signs strongly pointed towards COP, that was confirmed and responded brilliantly to corticoid treatment.

To complete the presentation, I am showing two more examples of reversed halo and migratory infiltrates (CASES 1 and 2, below).

CASE 1. 61-year-old woman with COP and basilar infiltrates (A, arrows). During treatment, coronal and axial CTs show bilateral and symmetrical reversed halo signs (B and C, arrows)

CASE 2. 51-year-old woman with COP and migratory pulmonary infiltrates (A and B). The second CT shows nice examples of reversed halo sign (B, circle), better seen in the cone down axial view (C, arrows).


Follow Dr. Pepe’s advice:

1. Localized cryptogenic organizing pneumonia may mimic other pulmonary processes

2. Migrating infiltrates and reverse halo sign (or both) are helpful in suspecting COP

Emergency #27 – Flashcard

Elbow pain after a fall. What do you see?

Click here to see the answer

Findings

Large joint effusion with the displacement of the anterior fat pad. Mild posterior soft tissue swelling over the olecranon. Fracture line along the lateral aspect of the radial neck. Radial head and articular surface are normal

Diagnosis

Nondisplaced radial head fracture

Teaching points

– Check not only the bones and joints but also the soft tissues
– Search and interpret the findings in two different positions
– Pain always withholds a story behind

Cáceres’ Corner Case 255

Dear friends,

today I am presenting preoperative chest radiographs for knee surgery in a 47-year-old woman.

More images will be shown on Wednesday.

What do you see?

Click here to see the new images

Click here to see the answer

Findings: PA chest radiograph shows a bump in the left hemidiaphragm (A, arrow). It is partially hidden in the lateral view by the shadow of the right hemidiaphragm and the cardiac silhouette (B, arrows).

Diaphragmatic bumps are common on the right and rarer on the left, especially in young persons. I was curious about this finding and reviewed an abdominal CT done a few weeks earlier. Enhanced axial, coronal and sagittal images demonstrate an intact diaphragm and a fluid-filled structure in the thoracic side (C-E, arrows). The appearance is typical of a diaphragmatic cyst.
 
Diaphragmatic cyst is a congenital lesion, asymptomatic and absolutely harmless. It is easy to demonstrate with CT and should not be removed. They are rare (I have seen only four during my professional life). I thought it interesting to acquaint you with this rare entity.

Final diagnosis: congenital diaphragmatic cyst
 
Teaching point: not all diaphragmatic bumps are hernias or eventrations. When they occur in the left side in a young person, consider other possibilities, such as a congenital cyst or a fibrous pleural tumor.

Musculoskeletal #17 – Long Case

2-year-old girl, referring to emergency department after a fall.

What do you see?

Click here to see the answer

– An expansile lytic lesion with ill-defined margins (green arrow) is seen on the diaphysis of fibula.

– Lamellated periosteal reaction (red arrow) suggests an aggressive lesion.

Differential diagnosis of an aggressive lytic lesion in a 2-year-old child includes:
– Osteomyelitis
– Ewing’s sarcoma
– Langerhans cell histiocytosis
– Leukemia/lymphoma

What should be done next?

An MRI scan

Intramedullary hyperintense lesion with extensive surrounding soft tissue and bone marrow edema on coronal STIR image (a) is seen. The lesion is hypointense on T1 WI (b).

Cortical destruction is shown on axial PD image (arrow in c).

Postcontrast coronal (a) and axial fat-suppressed (b) T1-weighted images show extensive enhancement in the lesion and the surrounding soft tissue

Histopathologic examination revealed Langerhans cell histiocytosis.

Langerhans Cell Histiocytosis (LCH)

– LCH is characterised by idiopathic infiltration and accumulation of abnormal histiocytes within various tissues.

– Bone is the most commonly affected tissue in children, with a predilection for axial bones, and femur is the most commonly affected long bone.

– Radiographic appearance of the lesions depends on the site of involvement and the phase of the disease.

Skull: Calvarium is more affected than the skull base, typically seen as single or multiple well-defined lytic lesions on radiography; T1 hypointense, T2 hyperintense with significant enhancement on MRI. Temporal bone is the most common affected part of skull base seen as destructive lesions with a soft tissue component.
Spine: Vertebral bodies are affected with relative sparing of posterior elements. A typical vertebra plana appearance may be encountered with total collapse.
Long bones: Ill-defined lytic lesions with/without cortical destruction are seen usually located at diaphysis or metaphysis. Periosteal reaction may be present. Extensive bone marrow and soft tissue signal changes on MRI may also be helpful in the diagnosis.

Cáceres’ Corner Case 254 – SOLVED

Dear Friends,

today’s radiographs belong to a 34-year-old woman with moderate cough. Previous history of asthma.

What do you see?

Diagnosis:

1. Mucous plug
2. Segmental atelectasis
3. Tuberculosis
4. None of the above

Click here to see the answer

Findings: Pa chest radiograph shows a tubular opacity that seems to arise from the right hilum (A, arrow). The lateral chest (B) does not show any abnormality, which raises the possibility that the opacity in the PA view is spurious.

Careful inspection demonstrates that the opacity extends to the right apex and to the neck (C, red arrows). The appearance is typical of a superimposed pigtail.

Some of you described the slightly elevated minor fissure. It is an unfortunate coincidence, probably related to previous episodes of mucous plug in an asthmatic patient causing mild loss of volume of RUL.
 
Final diagnosis: Pigtail simulating pulmonary disease.
 
Congratulations to MK who was the only one to suggest the correct diagnosis.
 
Teaching point: You may think that I tricked you, but it was not my intention. This case is a reminder that apparent pulmonary opacities may be located in the pleura, chest wall or outside of the body.
 
To emphasize this point I am showing two more cases of braids simulating pulmonary disease, presented in earlier blogs.

CASE 1. 48-year-old woman with mild cough. PA radiograph shows an ill-defined opacity in the left lung, running from top to bottom (A, white arrows). The opacity extends towards the neck (A, red arrow), which suggests that it is external to the lung. Lateral view shows an elongated opacity in the back of the chest (B, arrows).

A photo of the patient (C) confirms that a long braid is the cause of the opacity. PA radiograph after lifting the braid demonstrates that the chest is normal (D).

CASE 2. 25-year-old man with braided hair simulating a RUL infiltrate (A, arrow). The opacity extends to the neck, giving away the diagnosis (A, red arrow). After raising the braid, the chest looks normal (B). Remember that men also wear their hair long nowadays.

Neuroradiology #25 – Flashcard

What do you see? What is the most likely diagnosis?

Click here to see the answer

Multiple sclerosis

Multiple white matter lesions involving the corpus callosum, peri-trigone region, subcortical, and deep white matter.
Ddx: other demyelination, vasculitis, small vessel disease, tosic/metabolic, watershed infarcts.