Musculoskeletal #16

63-year-old patient with knee pain. What do you see?

Click here to see the answer


Lucent distal femur epiphyseal lesion with thin sclerotic borders and rings-and-archs calcifications, characteristic of chondral matrix

What is the most likely diagnosis?



Malignant counterpart chondrosarcoma in spinous process of lumbar spinal vertebra

What do you see?

Click here to see the answer

Teaching points

Characteristic findings: location epiphysis, thin sclerotic borders and rings-and-archs calcifications
It might be indistinguishable from chondrosarcoma on imaging, and pain may raise the latter suspicion
If bone aggressive lysis, striking endosteal scalloping or soft tissue component is present,

Cáceres’ Corner Case 253 – SOLVED

Dear Friends,

Today’s case is a PA chest radiograph for knee surgery in a 28-year-old man.

What do you see?

Click here to see the answer

Findings: PA chest radiograph shows an osteochondroma in the right humerus (A, yellow arrow). There are two more in the anterior arch of the left fifth rib and in the proximal end of the right clavicle (A, red arrows).
They are better seen in the cone down views (B-D, arrows).

The first and only diagnosis that comes to mind is multiple osteochondromatosis, confirmed with views of the lower extremities (E-G).

Final diagnosis: Multiple osteochondromatosis.
Most of you did very well in this case. Congratulations to Mauro, who was the first and to Kaushalya and Ali who made back-to-back diagnosis in a five-minute interval.
Teaching point: remember to look at the bones of the chest, especially when taking an examination. It may surprise the examiner and win you a few extra points.

Dr. Pepe’s Diploma Casebook 168 – Solved!

This week’s case is a little special! Prof. Cáceres has prepared a Quiz that will to challenge your knowledge and your speed reviewing radiographs! The quiz contains 7 different cases with radiographs and you will have 60 seconds to answer each question! The three participants with highest score will receive a signed picture of Dr. Pepe 😀

Are you up for the challenge? Join the quiz here It will start on Thursday 18th, at 12:00 CET.

On Friday Prof. Cáceres will publish the explanation for each case on the blog.



71-year-old man with hemoptysis:

In which quadrant will you place the lesion?

1. Right upper quadrant
2. Right lower quadrant
3. Left upper quadrant
4. Left lower quadrant

Click here to see the answer

Findings: there is a rounded opacity behind the heart (A, arrow). CTs show a non-enhancing pulmonary mass with irregular borders attached to the pericardium (B-C, circles).
Post-operative diagnosis: mucoid carcinoma of the lung.



43-year-o.ld male with moderate cough.

Most likely diagnosis:

1. Tuberculosis
2. Enlarged left pulmonary artery
3. Carcinoma
4. Any of the above

Click here to see the answer

Findings: PA radiograph shows that the left hilum is larger and more opaque than the right one (A, arrow). The pulmonary arch is prominent (A, red arrow). The lateral view shows an enlarged left pulmonary artery (B, arrows) excluding the diagnosis of carcinoma or TB as causes of hilar enlargement. Enhanced axial CT confirms the enlarged left pulmonary artery (insert, arrow).
Diagnosis: Congenital pulmonary valve stenosis with secondary dilatation of the left pulmonary artery due to the jet effect.



60-year-old man with chest pain.

In which quadrant will you place the lesion?

1. Right upper quadrant
2. Right lower quadrant
3. Left upper quadrant
4. Left lower quadrant

Click here to see the answer

Findings: there is a well-defined rounded left apical opacity (A, arrow), better seen in the cone down view (B, arrow)

Coronal and axial enhanced CT confirm the apical mass (C-D, arrows). The patient complained of pain in the left shoulder. Needle biopsy came back as adenocarcinoma.

Final diagnosis: Pancoast tumor



65-year-old man with cough and dyspnea


1. Unilateral hyperlucent lung
2. Pneumothorax
3. Giant bulla
4. Carcinoma of the lung

Click here to see the answer

Findings: the initial impression of the PA chest is a left hyperlucent lung with diminished vascularity. A second look shows a descended left hilum (A, arrow) and a concave paraspinal line (A, red arrow) representing the major fissure. These findings are indicative of LLL collapse with compensatory expansion of LUL.

Enhanced axial CT confirms the marked LLL collapse (B, arrow). Coronal reconstruction shows irregular bronchial narrowing (C, red arrow) with complete occlusion of the LLL bronchus.

Diagnosis: epidermoid carcinoma with LLL collapse.



33-year-old man with pain in the right hemithorax

Where is the nodule located:

1. Lung
2. Pleura
3. Chest wall
4. Need a CT

Click here to see the answer

Findings: PA radiograph shows a rounded opacity in the lower right chest (A, circle) with incomplete border sign (medial aspect outlined by air, lateral border not visible because in contact with chest wall). The clue to its location is given by the rib erosion (A, red arrow) which places the lesion in the underside of the rib. The border of the erosion is sclerotic, indicating a slow-growing process.
CT confirms a soft-tissue mass (B, circle) and the rib erosion (B-C, red arrows).

Final diagnosis: neurofibroma in a patient with neurofibromatosis.



32-year-old man with chronic cough

In which quadrant will you place the lesion?

1. Right upper quadrant
2. Right lower quadrant
3. Left upper quadrant
4. Left tower quadrant

Click here to see the answer

Findings: PA radiograph shows increased lucency of the lower right lung with decreased vasculature (A, circle). This finding has two main causes: increased lung air or paucity of lung vessels (pulmonary embolism, arterial stenosis). In these cases, the best approach is to take an expiratory film, which will demonstrate whether or not there is air-trapping. If present, it will orient us to a bronchial obstructive process, either central or peripheral

Coronal CT (B) confirms the increased lucency and diminished vasculature of RLL and RML. Scattered bronchiectasis are seen within the lucent lung (B-C, arrows).
Axial expiratory CT (D) demonstrates marked air-trapping of RML and RLL.

The patient had a history of swallowing a peanut at the age of five years, developing RLL pneumonia at that time. Control radiographs demonstrated increased lucency of the lower right lung over the years.
Final diagnosis: Lobar Swyer-James/McLeod syndrome secondary to aspiration of a peanut in childhood.



17-year-old woman with moderate cough

Most likely diagnosis:

1. Benign pulmonary nodule
2. Arteriovenous malformation
3. Pleural plaque
4. Artifact

Click here to see the answer

Findings: PA radiograph shows a rounded opacity in the periphery of the left lung (A, arrow) that seems to be calcified. Cone down view shows a whorled pattern (B, arrow). A braid is visible in the left supraclavicular area (A, red arrow).

Scout view of the CT does not show the apparent lung lesion, which is not visible in the axial view of the lung (D). The technician that did the CT noticed that the patient had a long braid with a rubber band at the end.

Final diagnosis: hair braid simulating a lung nodule.

Head and Neck #4 – Flashcard

CT – Coronal + C
CT – Axial + C
Where is the abnormality?​

Left side of the neck.

How can the abnormality be described?​

Multiple enlarged neck clustered lymph nodes, with some of them showing necrosis.

What is the differential diagnosis?

Infectious lymphadenitis: such as TB or pyogenic lymphadenitis.
Metastasis: particularly from head and neck malignancies.
Treated lymphoma or lymphoma in immune compromised patient.

What is the final diagnosis

TB lymphadenitis

Emergency #26 – Flashcard

A 30-year-old female with right shoulder pain.

4 images of the right shoulder were obtained (axillar, Y-view, internal rotation, external rotation)

Click here to see the images

Internal rotation
External rotation


Right shoulder: There is a nondisplaced fracture involving the inferior aspect of the glenoid, with involvement of the articular surface. Glenohumeral joint shows normal alignment. Acromioclavicular joint is normal. No soft-tissue calcification. No fracture or dislocation

What is the most likely diagnosis?

The most likely diagnosis is Hill-Sachs lesion

Hill-Sachs lesions are a posterolateral humeral head compression fracture. Typically occurs secondary to recurrent anterior shoulder dislocations. It is often associated with a Bankart lesion of the glenoid

Internal Rotation
External Rotation

These lesions are best seen following relocation of the joint. It appears as a sclerotic line running vertically from the top of the humeral head towards the shaft. A wedge defect may be evident in large lesions. The lesions are better appreciated on internal rotation views

Cáceres’ Corner Case 252 – SOLVED

Dear Friends,

Since this week is my birthday, I am showing a simple case. Chest radiographs were taken in a routine study for asbestos exposure in a 42-year-old man.

Will show more images on Wednesday.

Click here to see the images shown on Monday

Dear Friends,

showing today a cone down view of the lateral chest. What does the pattern suggest?

Click here to see the new images

Click here to see the answer

Findings: PA radiograph shows punctate opacities in the upper and middle thirds of the right lung. The right heart border is indistinct (A, circle) suggesting RML disease.

The lateral view confirms RML disease (B, circle). A cone down view demonstrates thick lineal branching lines (C, circle) highly suspicious of dilated mucous-filled bronchi.
(Branching structures in chest radiograph are either vessels or mucous -filled bronchi).

Unenhanced sagittal and axial CTs show bronchiectasis of RML and lingula (D-E, circles).

Final diagnosis: RML bronchiectasis detected in the lateral view of the chest
Congratulations to MK, who made the diagnosis.
Teaching point: I presented this case because it is a nice example of bronchiectasis with mucous impaction suspected in the plain film. I posted it on Monday without having seen the CT because whoever read it told me that bronchiectasis were present.
I reviewed the CT two days ago and was surprised to discover two vital findings
that I had not been told:
1. The CT showed centrilobular and tree-in-bud opacities (F-G, circles), typical signs of bronchiolitis.
2. These findings plus RML and lingular bronchiectasis are a classic presentation of atypical mycobacterial infection.

So, what started as an unsuspected discovery in the plain film ended up with the serendipitous diagnosis of atypical mycobacterial infection (unproven, but likely). The attending physician has been notified and when a germ is found I would let you know

Dr. Pepe’s Diploma Casebook 167 – Big little findings – SOLVED

Dear friends,
Presenting today a new case of “Big little findings”. This case is not recommended for the faint-hearted 😱
Chest images belong to a 65-year-old woman with moderate cough. Since I am your friend, I am including an axial CT.

What do you think?

Click here to see the answer

Findings: PA radiograph shows a curvilinear opacity in the right middle/lower lung (A, arrows). The right lung is slightly smaller than the left and the hilum looks abnormal (A, circle). Aside from slight elevation of the right hemidiaphragm, the lateral view (B) is unremarkable.

Coronal CT shows that the curvilinear line represents a scimitar vein draining below the diaphragm (C, arrow). The right pulmonary artery describes an unusual path (D, circle) and there is abnormal branching of the right main bronchus (D, circle).

An unexpected finding is an oblique band in the lower right lung (E and F, arrows). The bronchi and RLL vessels pass through an opening in the center (E and F, circles).

Final diagnosis: hypogenetic right lung with duplicated diaphragm

The reason I’m presenting this case is to discuss duplication of the diaphragm, an uncommon congenital malformation associated with hypogenetic lung.

As you all know, hypogenetic lung is a congenital malformation characterized by absence of one or two lobes of the right lung, with abnormal lower lung venous drainage (scimitar vein) in 80% of cases. It is asymptomatic and almost always occurs on the right side. Because it is symptomless, it is usually found incidentally in adults .

Typical signs in the PA chest radiograph (Fig. 1) reflect the small size of the lung:

1. Small right hemithorax with secondary dextrocardia
2. Small right hilum
3. Anomalous vein in RLL (scimitar sign), not always present

Fig. 1. PA radiograph (A) shows typical appearance of hypogenetic lung: small right hemithorax, secondary dextrocardia, and a scimitar vein (A, arrows) coursing downwards to join the IVC. Enhanced coronal CT in a different patient shows the scimitar vein to better advantage (B, arrow). Axial CT confirms the small right hemithorax and abnormal branching of the right main bronchus (insert, circle).

Occasionally, hypogenetic lung occurs with minimal hypoplasia, a normal-sized right lung, and absent dextrocardia. In these patients (such as the initial one), the scimitar vein and abnormal right hilum are the clues to the diagnosis.

In my experience, these cases are the ones most commonly associated with duplicated diaphragm, an infrequent malformation resulting from an alteration of caudal migration of the embryonic diaphragm.

Anatomically it appears as a band running obliquely from the chest wall to the right hemidiaphragm (Fig. 3, drawing).

If we’re lucky, we might see it as an oblique line in PA and lateral radiographs (Fig. 4), but it is usually not visible or overlooked (Fig. 5). An additional sign is blurring of the central part of the right hemidiaphragm, where the duplication ends (Figs. 4 and 5).

Fig. 3. Coronal and axial drawings demonstrating the appearance of the duplicated diaphragm (A and B, blue lines) and vessels crossing through the central orifice (A and B, in red).
Fig. 4. Duplicated diaphragm visible in the PA and lateral radiographs as an oblique band (A and B, white arrows). Note that the contour of the right hemidiaphragm becomes blurred where the duplicate joins it (A and B, red arrows). Axial CT confirms the duplicated diaphragm (C, white arrows) and crossing vessels (C, red arrow). A scimitar vein was not present in this patient.
Fig. 5. Blurring of the central right hemidiaphragm (A, red arrow) and an oblique line in the lateral view (B, red arrow) were present in the initial case, but they were overlooked. Signs in the chest radiograph can be too subtle. My advice is to rely on the CT findings.

My hard-learned experience tells me it is very difficult to suspect duplicated diaphragm on plain films. It is usually discovered in a CT performed to confirm a hypogenetic right lung or for other reasons.
The good news is that the CT findings are pathognomonic and consist of:

1. An oblique band with a central opening
2. RLL bronchi and vessels passing through the opening and fanning out thereafter

You may wonder why I present such a rare condition, but the answer is simple:

a) It is easily recognized because of the distinctive findings. Once recognized, advise against surgery or other invasive procedures.

b) I don’t believe it’s that rare. In my career I have seen a dozen cases, the last three in this century and at the same institution. The last, seen in 2015, is the one that headed this Diploma. Two more were seen in 2004 and 2008 (Cases 1 and 2, below).

I am due to see a new case soon. Perhaps in a COVID patient, allowing me to write a useless paper about the relationship between COVID and duplicated diaphragm 🙂

CASE 1. 56-year-old woman investigated for lymphoproliferative syndrome. Axial and coronal CT show an unsuspected duplicated diaphragm (A and B, white arrows) and the crossing vessels (A and B, red arrows).
CASE 2. CT requested for chronic bronchitis in a 44-year-old woman. Axial CTs document the complete duplicated diaphragm (red arrows), the vessels insinuating through it (B, circle) and lower down, the orifice with the vessels passing through (C, green arrow). White arrows point to the downward course of the scimitar vein before draining in the IVC.

Follow Dr. Pepe’s advice:
1. Duplicated diaphragm is an infrequent malformation associated with hypogenetic right lung

2. Difficult to detect in the chest radiograph

3. Easy to diagnose in CT images by the following signs:

a) Oblique band with a central hiatus in the right lower lung

b) Central hiatus that constricts RLL bronchi and vessels

Cáceres’ Corner Case 251 – SOLVED

Dear Friends,

Showing today radiographs of a 27-year-old man with fever and hemoptysis.
More images will be shown on Wednesday

What do you see?

Click here to see Monday images

Dear friends, attaching CT images of the chest and abdomen. Do they help?

Click here to see more images

Click here to see the answer

Findings: chest radiographs show a cavitated pulmonary lesion in the apical-posterior segment of the LUL (A-B, arrows). There is convexity of the left middle mediastinum
(A, red arrow).

Enhanced axial CTs show an irregular pulmonary mass with cavitations (C-D, arrows). The thymus is enlarged, with a central area of decreased density (D, red arrow).

Enhanced axial abdominal CTs demonstrate enlarged retroperitoneal lymph nodes
(E-F, circles) as well as enlarged mesenteric lymph nodes (E, red ellipse).

In summary, the findings are:
Cavitated lung mass. Etiology: TB, fungal infection, lymphoma, Wegener and other granulomatosis.
Enlarged thymus. Etiology: thymoma, germ-cell tumor, thymic lymphoma
Enlarged retroperitoneal and mesenteric lymph nodes. In my opinion, this is a crucial finding, because it is highly suspicious of lymphoproliferative disease.
Putting all the findings together, lymphoma is the most likely diagnosis.
In this patient the initial diagnosis was TB. No TB germs were grown from the bronchial aspirate and PPD was negative. Abdominal CT seven days after admission suggested the diagnosis of lymphoma, confirmed by biopsy, which demonstrated widespread Hodgkin disease, nodular sclerosis type.
Final diagnosis: Cavitated Hodgkin disease of the lung.

Congratulations to all of you who made a gallant effort to diagnose the case. Will single out Olena because she was the first to mention lymphoma.
Teaching point: As this case proves, cavitated lesions of the lung are difficult to diagnose by chest imaging alone. Sometimes you need all the help you can get.

Dr. Pepe’s Diploma Casebook 166 – Big little findings – SOLVED

Dear friends,

I am starting a new section named “Big little findings”. The aim is to emphasize the importance of discovering subtle findings that should not be missed. They are easily seen if you know what to look for.

Today I’m showing preoperative chest radiographs of a 69-year-old man with bladder carcinoma.

What do you see?

Click here to see the answer

Findings: the most important feature is a negative finding: absence of air in the gastric fornix (A, circle). Although this is sometimes seen in healthy persons, it is more frequent in distal esophageal obstruction. A careful look discovers that the left mediastinum has a double contour, actually the left wall of the dilated esophagus (A, blue arrow) and the descending aorta (A, red arrow). There is bulging of the right paraesophageal line (A, yellow arrow). A dilated air-filled upper esophagus is visible in the lateral view (B, arrows).

The findings are typical of lower esophageal obstruction with dilatation of the esophagus. The double contour of the left mediastinum is better seen in the cone down view (C, arrows) and confirmed with CT (D, arrows).

The air-filled dilated esophagus in the lateral view (E, arrows) is confirmed with sagittal CT (F, arrows) (T= trachea).

Final diagnosis: unsuspected esophageal achalasia

To my eternal shame, I confess that when I read the initial radiographs I overlooked the findings (nobody’s perfect!). Achalasia was discovered in a routine follow-up CT taken one year later. I redeemed myself in a subsequent pre-op PA radiograph of the patient, in which I saw a double contour of the descending aorta (A and B, red and blue arrows) and bulging of the paraesophageal line (A and B, yellow arrows). I missed the absent air in the gastric fornix, again!

Esophageal achalasia is not an uncommon condition, and early stages can be suspected in the chest radiograph if we pay attention to the telltale signs. Note that these signs are not specific for achalasia and can be secondary to any obstructive process of the distal esophagus. The most revealing findings are:

Absent gastric bubble
Displaced lower mediastinal lines
Air-fluid level in the mediastinum


Occurs in about 10% of the normal population and 50% of achalasia patients, and is due to failure of swallowed air to cross the distal esophageal sphincter. It is a negative finding and therefore, difficult to recognize. When it is detected, we should examine the lower mediastinum, looking for signs of esophageal dilatation (Fig. 1).

Fig. 1. 54-year-old man with moderate dysphagia. In the PA radiograph, there is no gastric bubble (do not confuse air in the colon – A and B, black arrows – with air in the gastric fornix). The paraesophageal line is convex (A, red arrow). These two signs are suspicious for achalasia, confirmed with barium swallow. Note the distal esophageal stenosis (B, white arrow).


A dilated esophagus displaces the paraesophageal line toward the right, making it convex. The left wall of the esophagus moves outward, and is sometimes seen as a double contour with the descending aorta (Figs. 2 and 3). Convexity of the paraesophageal line is the most reliable sign and the easiest to detect.

Fig. 2. 48-year-old. woman with achalasia. Initial film shows a normal mediastinum with a visible gastric bubble (A, black arrow). Four years later (B) the gastric bubble is absent. There is a second contour (B, red arrow), paralleling the aorta (B, black arrow). Note that the initial concave paraesophageal line has become straight four years later (A and B, yellow arrows). Esophagogram confirms the esophageal dilatation and the narrow esophagogastric junction (C, red arrow).
Fig. 3. 47-year-old man with dysphagia. PA radiograph shows a convex paraesophageal line (A, white arrow). There is also a convex line on the left (A, red arrow). CT confirms the dilated esophagus containing air and fluid (B and C, asterisks). Diagnosis: esophageal achalasia.


Excluding hiatal hernia, an air-fluid level in the mediastinum is usually located in the esophagus. It is seen as a straight horizontal line in the middle/upper mediastinum. It is usually related to esophageal obstruction of any cause, the most common being achalasia. Discovery of an air-fluid level should lead us to investigate other signs of esophageal dilatation (Figs. 4 and 5).

Fig. 4. 47-year-old woman with dysphagia. PA radiograph shows an air-fluid level in the upper mediastinum (A, red arrow) accompanied by bulging of the paraesophageal line (A, white arrow) and absent gastric fornix. Esophagogram: dilated esophagus with distal stenosis (B, arrow) typical of achalasia.
Fig. 5. Showing this case because it’s a beauty. 73-year-old man referred by the pulmonologist to investigate chronic cough. PA and lateral chest radiographs show a dilated esophagus containing mainly air (A and B, white arrows), with a distal air-fluid level (A and B red arrows). Axial CT confirms the dilated esophagus with retained food (Insert, arrow). Achalasia, confirmed. Air is visible in the gastric fornix in this case (A, black arrow).

Aspiration pneumonia is a complication of achalasia. I’m showing two cases in which the signs mentioned helped to suggest the correct diagnosis (Figs. 6 and 7).


55-year-old man with pancreatic carcinoma and known achalasia who presented with marked cough. Chest radiographs show bilateral airspace infiltrates. In the PA view there is also dilatation of the upper esophagus (A, white arrows) with an air-fluid level (A, red arrow). The lateral view shows a retrocardiac mass (B, white arrow), suggestive of a dilated lower esophagus. The trachea is displaced forward (B, red arrow). These signs were overlooked by the radiologist, whose diagnosis was widespread pneumonia.

Coronal CT demonstrates widespread air-space disease. It also shows a dilated esophagus (C, arrow). Axial CT images confirm dilatation of the esophagus, which is full of residue
(D and E, arrows).
Final diagnosis: esophageal achalasia with secondary aspiration pneumonia.


This an old case of a 27-year-old woman with a chronic RUL opacity suspected to be TB (disregard the opacities in both middle lung fields, caused by superimposed breast implants).
PA chest radiograph shows an opacity in the right upper lobe (A, circle). A right paramediastinal line extends from top to bottom (A, arrows). The lateral view shows anterior displacement of the trachea by a tubular structure (B, arrows), which occupies the upper and middle mediastinum. Both findings suggest a dilated esophagus.
Barium swallow confirms the dilated esophagus, secondary to narrowing at the esophagogastric junction (insert, arrow). Considering the age of the patient, achalasia with aspiration pneumonia was the most likely diagnosis, confirmed later.
(Remember that aspiration pneumonia goes to the right upper lobe when the patient is recumbent at night).

Follow Dr. Pepe’s advice:

Subtle findings of distal esophageal obstruction (achalasia) that should not be overlooked:

1. Absent gastric bubble

2. Displaced lower mediastinal lines

3. Air-fluid level in mediastinum