Noon Case Conference— January 10th, 2023
The middle of the chest
Howard Mann, M.D.
University of Utah School of Medicine
howard.mann@utah.edu
howardmann.us
Instructions for viewing the cases
- use your keyboard arrow keys to navigate through the slides
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fon your keyboard; hitescto exit - mouse-click through the Tabs; start and end each case with the
PresentationTab - there is a menu
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icon bottom-left that you can use to navigate as well. - please volunteer to discuss a case(s) during the conference!
icon bottom-left that you can use to navigate as well.Case one
A very astute observer questioned a finding on chest radiography.
A CT was subsequently obtained.
Discuss…
The lesion was removed and is an Ectopic Thymoma.
A solitary solid lesion in this location is a conundrum. It’s not a typical location for an enlarged lymph node, for example.
It may be impossible to precisely determine its origin, for example, mediastinum or pleural membrane.
A thymoma typically develops in the retrosternal, anterior mediastinum — except when it doesn't!Case two
An observer noticed rightward deviation of the trachea on chest radiography and an abnormal right mediastinal-lung interface.
A CT was performed.
This is typical of intra-thoracic extension of a goiter — from the left thyroid lobe in this instance.
It demonstrates an admixture of regions of relatively high attenuation — iodine-containing tissue — and low attenuation. The latter may be attributed to processes of “degeneration”: cystic regions; prior hemorrhage; fibrotic regions.
Dystrophic calcifications are present — common in multinodular goiter.
A diagnosis -- ectopic thyroid tissue -- may be made even if there is no connection with a thyroid lobe.Case three
Chest radiography was performed for chest discomfort.
Review the imaging and then…
Address the following questions one at a time in your response:
- Where is the abnormality located ?
- Offer a (limited!) Differential Diagnosis
- What single imaging procedure will be most informative ?
- The presence of the hilum overlay sign permits the localization of the lesion to the posterior, paraspinal mediastinum.
- A mass arising from the posterior pleura (such as a solitary fibrous tumor) may produce the same findings.
- A pulmonary mass of this size would very likely displace adjacent pulmonary vessels.
The imaging findings on MRI are typical of a nerve sheath tumor—Schwannoma.
Reference: Crist, et al. Magnetic Resonance Imaging Appearance of Schwannomas from Head to Toe: A Pictorial Review. J Clin Imaging Sci. 2017; 7: 38.
Case four
A CTPA performed for possible acute pulmonary embolism did not show emboli.
Again, address the following one at a time in your response:
What is present ?
Offer a limited Differential Diagnosis.
Dare to offer a (confident!) diagnosis.
Diagnosis: Paraganglioma
- a para-aortic mediastinal mass is present
- intense contrast-enhancement1 of it—except in its center—is present
Key points
- mediastinal paragangliomas usually originate from
para-aortic (middle mediastinum) and para-vertebral
(posterior mediastinum) sympathetic chain ganglia
- most are not "functioning" lesions
- they are typically very vascular tumors
Epithelioid cells with oval to round nuclei are arranged in nests/clusters known as zellballen (cell ball). An extensive network of branching sinusoidal vessels intervenes between the nests of tumor cells1.
Source: Gardner, J.
Case five
This CT was performed in a 35-year-old male with acute, central chest pain. He is convinced he is having a heart attack
A high-sensitivity troponin assay is “negative.”
Review the CT and address the following one at a time in your response:
What finding is not present ?
What finding is present ?
Offer a certain explanation for the pain.
Diagnosis: Spontaneous (sporadic) necrosis of mediastinal fat.
- the location in this case is typical
- a small pleural effusion is present, a common concurrent finding
- this is analogous to the entity of epiploic appendagitis in the abdomen
Case six
A CTPA in a 45-year-old woman did not reveal pulmonary emboli.
Something unexpected was perceived.
What ?
What is a sufficient explanation ?
If you could see the patient, you would observe this:
Diagnosis: True Thymic Hyperplasia
- substantial thymic tissue is present, without rounded, mass-like morphology ⟶
- a known association with Grave’s disease.
- further evaluation with chemical-shift MRI (to establish the presence of internal fat) is not usually necessary
- aberrant origin of the right subclavian artery is an unrelated finding
Case seven
Persistent chest pain in a 28-year-old patient.
describe the findings
where is the abnormality located ?
provide a limited differential diagnosis
if this were a male instead, what should be further evaluated by means of physical exam and an ultrasound as part of the work-up?
Findings on radiography
- the opacity effaces normal left supra-azygos (right paratracheal) and left supra-aortic mediastinal-lung interfaces; the distal aortic arch (knob) is not effaced
- the trachea is narrowed
- thus substantial superior and anterior mediastinal tumor mass is present, traversing the thoracic inlet
- a lymphoma is by far the most likely explanation; a primary or metastatic germ cell tumor is a consideration—in a male, a scrotal examination and testicular ultrasound should be performed
Hodgkin Lymphoma 
Case eight
An abnormal opacity was perceived on frontal chest radiography—in the right-cardiophrenic region effacing the usual lateral margin of the inferior right atrium.
A CT was performed.
The radiograph is not available for review.
- describe the findings
What is the diagnosis ?
(A differential diagnosis is not relevant.)
Findings
- ascites is present a
- a small hemidiaphragm defect is present at the Foramen of Morgagni ⟶
- ascitic fluid has passed through this defect to accumulate in a hernia sac at the right cardiophrenic angle
Case nine
The patient complained of mild chest pain at a post-operative clinic visit. A mediastinoscopy (to biopsy right paratracheal and ? subcarinal nodes) was performed three weeks before.
He does not have a fever.
describe the findings
provide a very limited Differential Diagnosis – if you can!
View also the image in the next Tab.
Findings
- small amounts of fluid are present in the mediastinum in the lower pre-tracheal…
- and subcarinal mediastinum, where a tiny amount of gas is present ⟶
- the findings suggest the possibility of post-procedure infection…
- unless you become aware that the surgeon packed this area with Surgicel® Fibrillar as a hemostatic agent. It holds onto fluid and air for some time.
Go figure…It’s a gotcha!
Case ten
This is an employer-mandated, pre-employment radiograph.
Offer one—very likely—diagnosis.
Findings
- enlarged mediastinal and hilar lymph nodes are present *
- the most likely explanation for this distribution in an asymptomatic patient—by far— is Sarcoidosis
Case eleven
This patient reports dysphagia of yearslong duration.
Describe the findings and suggest the most likely diagnosis.
What (old-fashioned) procedure would you suggest to verify your diagnosis ?
Yes, the findings are subtle!
- an abnormal mediastinum-lung interface ⟶
- air-distention of the upper esophagus ⟶
Contrast esophagram
Esophageal achalasia
Case twelve
This patient is asymptomatic at present.
The CT was done after someone described an abnormality on a radiographic examination.
Is there really a differential diagnosis ?
Most-relevant finding: The para-cardiac lesion is a water-containing structure w
This, and its location, enables a confident diagnosis: Pericardial cyst
They may occur on the left side also!
It it were located in the retro-sternal, anterior mediastinum, describe it as a Thymic cyst.
Case thirteen
The patient reports chest pain of several months’ duration.
Share your thoughts.
Be bold and suggest one confident diagnosis.
It’s the last case!
Findings
- on radiography, it’s hard to know whether it’s in the lung or mediastinum
- the key finding on CT is the presence of intra-lesional fat f
- this lesion typically manifests on CT as a heterogeneous anterior mediastinal mass containing soft-tissue, fluid, fat, or calcium/bone, or any combination of the four
- the location in this case is, of course, unusual
We’re done
