Musculoskeletal #3 – Long case

Axial CT abdomen bone window

Axial CT abdomen soft tissue window

Where is the lesion?

Left iliac bone

What are the radiological characteristics/findings?

Large lytic lesion with wide zone of transition, cortical destruction, and large soft tissue component.
No specific matrix.

What is the differential diagnosis of an aggressive iliac bone lesion?

* Metastasis
* Plasmacytoma: solitary plasma cell tumor expansile lytic lesion with bone destruction and soft tissue component. Usually shows low signal intensity on T2 with variable post contrast enhancement. 
* Chondrosarcoma: malignant cartilage tumor destructive lytic lesion with intralesional rings and arcs calcification (chondroid matrix). High signal intensity on T2. 

What is the most likely diagnosis?

Plasmacytoma

Dr. Pepe’s Diploma Casebook: CASE 144 – SOLVED

Dear Friends,
presenting chest radiograph of a 77-year-old man with malaise and weight loss.
What do you see?

This is the last case before the summer. Will see you again in September. Enjoy your vacation!

Click here to see the images


Click here to see the solution

Findings: PA radiograph shows increased opacity of the left hilum (A, arrow), which is due to a mass projected over it, as seen in the lateral view (B, arrows). In addition, there is convexity of the aortopulmonary window (A, red arrow)

The increased hilar opacity (C, arrow) was not visible in a PA radiograph taken six months earlier (D, circle). Convexity of the aortopulmonary window (C, red arrow) was not present at that time.

In the lateral view, the mass (E, arrows) was visible six month earlier, albeit smaller (F, arrow). This progression indicates rapid growth.

Enhanced axial and coronal CT confirms a pulmonary mass invading the aortopulmonary window (G and H, arrows). Lung metastases were present (insert, red arrows)

Diagnosis: lung carcinoma invading the aortopulmonary window

I am presenting this case to discuss the aortopulmonary window (APW), which is a small mediastinal space located between the aortic knob and the pulmonary artery in the PA view (Fig 1A). The APW is normally concave; convexity (Fig 1B) suggests an abnormality that should be studied with enhanced CT.

Fig. 1.

Visibility of the APW is difficult in the elderly, because the superimposed uncoiled descending aorta makes the interpretation more difficult (Fig 2).

Fig 2. 67-year-old man with moderate dyspnea. A calcified lymph node (A-D, red arrows) marks the APW, which is hidden in the PA view by the elongated descending aorta.

Convexity of the APW may be overlooked unless we look specifically at the area (fig 3). The larger the abnormality, the more readily it is detected in the chest radiograph. Subtle changes are more difficult to identify and comparing with previous films is very helpful.

Fig. 3. 55-year-old man consulting for acute chest pain. PA film shows two Hampton humps in the right lower lung (A, white arrows). The left hilum is abnormal (A, red arrow). Enhanced coronal CT confirms the infarcts (B, white arrows), as well as a pulmonary mass (B, red arrow) and lymphadenopathy in the APW (B, yellow arrow). Findings were overlooked in a radiograph taken seven months earlier (C, yellow and red arrows). Proven bronchogenic carcinoma.

Causes that may alter the APW are: tumors, enlarged lymph nodes, aortic aneurysms and increased mediastinal fat. The phrenic nerve crosses this space and a phrenic neurinoma may also grow in the APW, although I have never seen a case.

Enlarged lymph nodes are by far the most common cause of occupation of the APW. They may occur in malignant and non-malignant diseases. They usually coexist with radiographic manifestations of the primary process (Figs 4 and 5).

Fig 4. 59-year-old man with apical LUL carcinoma (A and B, arrows). There is a marked bulge of the APW (A and B, red arrows). Moderate pneumothorax after needle biopsy.

Coronal and axial CT confirm metastatic lymph nodes in the APW (C and D, red arrows)

Fig 5. 33-year-old woman with low-grade fever and malaise. Chest radiographs shows a non-descript infiltrate in the anterior segment of the RUL (A and B, arrows). In addition, there is a prominent bulge in the APW, highly suspicious of lymphadenopathy (A, red arrow). Diagnosis: Hodgkin lymphoma.

In isolated occupation of the APW the etiology cannot be determined in the chest radiograph and enhanced CT should be obtained (fig 6).

Fig 6. Routine check-up in a 60-year-old woman. PA radiograph shows moderate convexity of the APW (A, arrow). Enhanced CT confirms enlarged lymph nodes in the APW (B and C, arrows), mediastinum and hila. Diagnosis: sarcoidosis

Aortic aneurysm is an uncommon cause of convexity of the APW (Fig 7). The abnormality is initially subtle and it becomes more evident as the aneurysm grows (Fig 8).

Fig 7. 78-year-old man without significant symptoms. PA radiograph shows a mediastinal mass protruding at the level of the APW (A and C arrows). The mass is also evident in the lateral view (B and D, arrows).

Radiographs taken five years earlier did not show the abnormality (E and F, circles).

Enhanced axial and coronal CT demonstrate that the mass represents a saccular aneurysm arising from the aortic arch (G and H, arrows).

Fig 8. 78-year-old man after a fall. PA radiograph shows numerous rib fractures (A, white arrows). An additional finding is a mediastinal opacity at the APW (A, red arrow), also visible in the lateral view (B, red arrow).

Comparison with previous films shows a normal APW in 2007 and progression of the opacity over a three-year period (arrows).

Enhanced CT shows that the opacity represents a partially thrombosed aneurysm arising from the inferior aspect of the aortic arch (C-D and E, arrows).

Last but not least, we should remember that mediastinal fat is an innocuous cause of convexity of the APW (Fig 9).

Fig 9. Asymptomatic 57-year-old man with superior mediastinal widening (A, arrow) and discrete convexity of the APW (A, red arrow). Coronal CT shows that the changes are due to mediastinal fat (B and C, arrows).


Follow Dr. Pepe’s advice:

1. Convexity of the APW suggests underlying pathology.

2. Enlarged lymph nodes are the most common cause of a convex APW.

3. Aneurysm and mediastinal fat may also enlarge the APW

Cáceres’ Corner Case 208 – SOLVED!

Dear Friends,

Presenting today radiographs of a 65-year-old man with back pain.

What do you see?

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Findings: PA chest radiograph shows an ill-defined opacity in the right middle lung field (A, asterisk), located in the anterior clear space in the lateral view (B, arrows). The anterior arch of the 4th right rib is missing.

A cone down view demonstrates an expanding lytic lesion in the anterior arch of the 4th right rib (C, asterisk), confirmed with CT (D and E, red arrows).

I thought this was an easy case, but I am disappointed because some of you missed a collapsed vertebra (F, circle), not present three years earlier (G, circle). Sagittal CT confirms it as well as additional affectation of L1 and posterior elements of D10 (H, red arrows).

In a patient with a port-a-cath, the presence of multiple lytic lesion suggests metastatic disease as the first possibility.
 
Final diagnosis: Carcinoma of esophagus with bone metastases

Congratulations to Andy, who was the first and to Archana Reddy.t who discovered the collapsed vertebra.

Teaching point: this case is similar to the previous one and the teaching point is the same: look at the underlying rib. And, above all, don’t forget to examine the rest of the bones!

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?

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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

Summary

* 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?

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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).

Summary

* 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?

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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)