Model Answers
Case 1
Case 1 Model Answer:
Findings and interpretation:
Chest radiograph:
- The right lung is over-inflated, causing mild contralateral mediastinal shift.
- There is an area of hyper-lucency in the right lung at the mid-zone peripherally, which shows a paucity of vessels.
CT abdomen:
- The imaged lower lungs confirm the findings noted on the radiograph, showing hyper-lucency and hyper-inflation in the right lower lobe with paucity of vessels.
- The upper poles of both kidneys show somewhat wedge-shaped yet ill-defined regions of hypo-enhancement.
- There is regular, circumferential thickening of the bladder wall.
- There is a small amount of free fluid in the pelvis.
The findings represent a congenital developmental abnormality in the lung, and unrelated inflammatory pathology in the urinary tract.
Principal diagnosis:
Congenital lobar over-inflation in the right lung with concurrent bilateral lobar nephronia and cystitis.
Differential diagnosis:
- Lung lesion: Swyer James syndrome, bronchial atresia.
- Kidneys: Renal infarction, renal lymphoma.
Management:
Alert referring physician of findings.
Case 1 Your Answer:
Case 2
Case 2 Model Answer:
Findings and interpretation:
US neck:
- There is a solid nodule in the left lobe of the thyroid gland, measuring approximately 11mm in greatest dimension; it is hypoechoic, is taller than it is wide, contains punctate echogenic foci (representing calcifications) and shows internal vascularity on the colour Doppler images. It extends past the border of the thyroid gland.
- There are left carotid chain round lymph nodes which are enlarged, are rounded and show loss of the normal lentiform shape, and demonstrate loss of the fatty hilum.
MRI abdomen:
- There is a well defined, round retroperitoneal soft tissue mass adjacent to the IVC; it shows T2 hyper-intensity and T1 hypo-intensity with a central area of high T1 signal intensity and low T2 signal intensity.
- The mass shows avid heterogeneous arterial phase post contrast enhancement; the central area shows no enhancement. The mass shows more uniform yet persistently heterogeneous enhancement on the portal venous phase, with persistent non-enhancement of the centre.
Incidental:
- There are two sub-centimetric T2 hyper-intense lesions in the liver in segment VIII, likely representing haemangiomas.
The findings in the neck represent a TR5 thyroid nodule, highly suspicious for thyroid carcinoma.
The findings in the abdomen represent a highly vascular retroperitoneal neoplasm with a haemorrhagic centre, which shows non-aggressive features.
Principal diagnosis:
Sympathetic extra-adrenal paraganglioma and medullary thyroid carcinoma. The patient likely has multiple endocrine neoplasia type II (MEN2).
Differential diagnosis:
Paraganglioma:
- Nerve sheath tumour
- Lymphoma
Thyroid:
- Different type of thyroid cancer
- Colloid nodule
Management:
Alert referring physician of findings.
FNAC for the thyroid nodule and lymph nodes.
Refer to neuro-endocrine tumour MDT to discuss further investigation by MIBG scan, and correlation with serum and urinary catecholamines.
Case 2 Your Answer:
Case 3
Case 3 Model Answer:
Findings and interpretation:
- There is a posterior fossa lesion extending from the medulla to the upper cervical cord at C2 level; it is intra-axial, arising from the posterior aspect of the medulla.
- The lesion is mostly cystic, showing CSF T2 hyperintensity and T1 hypointensity; however, there is a small eccentric nodule at the caudal aspect of the lesion which is solid, showing heterogeneous T2 hyper-intensity with flow voids on the FLAIR sequence at the periphery.
- The solid nodule shows avid post-contrast enhancement.
- The lesion exerts mass effect on the caudal aspect of the 4th ventricle, effacing it.
- There is T2 hyperintensity centrally in the cervical cord.
Pertinent negative findings:
- There is no significant hydrocephalus.
The findings represent a vascular posterior fossa neoplasm.
Principal diagnosis:
Haemangioblastoma.
Differential diagnosis:
- Pilocytic astrocytoma
- Medulloblastoma
Management:
Refer for discussion at neurosurgery MDT.
Consider genetic testing for Von Hippel Lindau disease.
Case 3 Your Answer:
Case 4
Case 4 Model Answer:
Findings and interpretation:
- There is a large lateral ventral hernia sac containing a loop of small bowel with its mesentery and omental fat. The sac herniates through the linea semilunaris between the rectus abdominus and the internal & external oblique muscles.
- There are two transition points of the small bowel where the loops enter and exit and the hernia sac.
- There is a moderate degree of focal fat stranding within the hernia sac, suggesting incarceration of the hernia.
- There is dilatation of the small bowel loops proximal to the herniated loop of bowel, which also show multiple air-fluid levels and fecal matter.
Pertinent negative findings:
- There are no signs of bowel ischemia to suggest strangulation.
The findings represent an incarcerated lateral ventral herniation of a small bowel loop, causing mechanical bowel obstruction proximal to it.
Principal diagnosis:
Spigelian hernia with an incarcerated small bowel loop causing mechanical obstruction.
Differential diagnosis:
- Strangulated hernia.
Management:
Urgently contact referring physician and inform of findings.
Urgent surgical management will likely be required.
Case 4 Your Answer:
Case 5
Case 5 Model Answer:
Findings and interpretation:
- There are large bilateral apical emphysematous bullae; that on the left side shows a thickened wall which likely indicates inflammation / infection.
- There is bilateral upper and middle lung zone centrilobular and paraseptal emphysema.
- There is a cluster of centrilobular nodules with surrounding ground glass opacification in the left upper lobe; this likely represents an infectious process.
- There are cystic arcades and larger interposed cysts on a background of ground glass opacification and interstitial / reticular thickening, more prominent in the lower lung zones / bases. There are also punctate calcifications and traction bronchiectasis in those regions (indicating fibrosis).
- There is a soft tissue mass with central foci of gas in the apical segment of the right lower lobe, abutting the pleura. This may represent a malignant neoplasm.
- There are a few prominent anterior mediastinal, pre-tracheal and hilar lymph nodes which are likely reactive in nature.
There is emphysema combined with fibrotic interstitial lung disease, with super-added localized pneumonia and a soft tissue mass suspicious for malignancy.
Principal diagnosis:
Combined emphysema and interstitial lung disease (probable UIP pattern), with super-added localized pneumonia and bronchial malignancy.
Differential diagnosis:
For interstitial lung disease:
- Desquamative interstitial pneumonia
- NSIP
For lung mass:
- Rounded atelectasis
Management:
Alert physician of acute findings.
Recommend discussion at pulmonary MDT regarding further management.
Recommend biopsy of soft tissue mass.
Case 5 Your Answer:
Case 6
Case 6 Model Answer:
Findings and interpretation:
Radiograph:
- There is an opacity located anterior to the ankle joint, deep to the subcutaneous fat.
MRI:
- There is a well defined soft tissue mass located anterior to the tibio-talar joint and deep to the extensor tendons of the foot.
- The mass displays intermediate signal on T1, low signal on T2 and high signal on the PD weighted images.
- The mass enhances avidly on the post contrast images.
Pertinent negative findings:
- The mass shows no involvement of the adjacent bones of the ankle joint or adjacent tendons and soft tissue structures.
The findings represent a musculoskeletal soft tissue mass related to the ankle joint, yet showing no aggressive features.
Principal diagnosis:
Teno-synovial giant cell tumour.
Differential diagnosis:
- Tendon sheath fibroma
- Desmoid tumour
Management:
Biopsy may be considered.
Surgical excision is the conventional management.