Arnold Chiari I malformation with syringomyelia

Findings and interpretation:

• The cerebellar tonsils are herniating caudally into the foramen magnum to a small extent, and show peaking of the inferior aspect.
• There is effacement of the cisterna magna and crowding of the brainstem structures at the foramen magnum.
• The cervical spinal cord is uniformly enlarged, showing fluid signal intensity on the T2 sequence with low signal on T1 centrally, with a thin rim of surrounding tissue.
• There is a small cyst in the medulla showing T2 signal matching that of CSF, with signal void matching that of CSF on the FLAIR sequence.

Pertinent negative findings:

• There is no evidence of obstructive hydrocephalus.
• No enhancement of the cervical spinal cord on the post-contrast images.

Incidental findings:

• There are degenerative cervical spine changes with loss of disc height and T2 signal intensity, as well as multi-level central bulge.

The findings represent a congenital structural malformation of the posterior fossa structures, with associated cystic abnormality of the cervical spinal cord caused by obstruction of CSF flow. The smaller localized cyst indicates separate hydromyelia while the central collection of CSF represents syringomyelia.  

Principal diagnosis:

Arnold Chiari I malformation with associated syringomyelia.

Differential diagnosis:

• Hydromyelia rather than syringomyelia
• Chiari 1.5/2 malformation
• Basilar invagination

Management:

Alert referring physician of findings.

Recommend neurosurgical referral.

Post Transplant Lymphoproliferative Disorder

Findings and interpretation:

• There is moderate to marked splenomegaly with prominent splenic varices at the hilum of the spleen. There are multiple small hypo-enhancing lesions scattered throughout the spleen, mostly uniform in size.
• Surgical clips are seen at the medial border of the liver allograft. Multiple hypo-enhancing lesions that are also small and uniform in size are seen scattered throughout the liver.
• There are multiple enlarged coeliac group and peri-aortic lymph nodes with low density centres. The largest one lies adjacent to the origin of the SMA and measures 3 – 5 cm in diameter.
• Some of the small, hypo-enhancing lesions are also seen in both kidneys, to a much lesser extent than the liver and spleen.
• There is a subcutaneous lesion which also demonstrates peripheral enhancement and hypodensity of the centre, located anterior to the xiphisternum.
• There are multiple scattered lytic bony lesions located in the vertebral bodies of the lumbar and lower thoracic spines.

Pertinent negative findings:

• There is no thickening of the small bowel.

In correlation with the surgical history provided, the findings most likely represent a lympho-proliferative disorder involving the solid visceral organs, axial skeleton and lymph nodes at multiple sites. The splenic varices indicate portosystemic collaterals due to portal hypertension.

Principal diagnosis:

Post-transplant lymphoproliferative disorder.

Differential diagnosis:

• Multi-system tuberculosis (the bony lesions do not fit with this diagnosis)
• Sarcoidosis
• Multiple myeloma (bony lesions only)

Management:

Alert referring physician of findings.

Refer for oncology MDT to discuss further management / treatment options.   

Osteogenesis imperfecta

Findings and interpretation:

Radiographs at 1 week of age:

• There is a fracture at the diaphysis of both the right and left femora.
• There is a bowing deformity of the left femur and both tibiae. Bowing deformity is also demonstrated in the ribs and the left humerus.
• There is a fracture of the right radius.

Radiographs at 2 years of age:

• More pronounced bowing deformity is demonstrated in the femora and tibiae.
• There is pronounced callus formation surrounding the left femoral diaphysis at the site of the previous fracture. A lucent line at this site indicates mal-union of the fracture.
• There are horizontal sclerotic lines at the metaphyses of the long bones.
• There is generalised osteoporosis.

The findings indicate a generalised, congenital musculoskeletal abnormality causing weakening of the long bones with multiple consequent fractures. Growth lines are demonstrated in the long bones as sequelae of bisphosphonate therapy.

Principal diagnosis:

Osteogenesis imperfecta (most likely type III)

Differential diagnosis:

• Non-accidental injury
• Hypophosphatasia

Management:

Inform referring physician of findings if diagnosis not already known, as well as active issues (such as mal-union of the femoral fracture).

Refer for discussion at orthopaedic MDT with regards to further management.

Findings and interpretation:

• There is a large, well defined mass extending from the left upper quadrant to the mid-abdomen. This appears to originate from the pancreatic tail and body as it is inseparable from pancreatic parenchyma.
• This is exerting mass effect on the splenic vein, causing compression with resultant splenic varices extending anterior to the mass. There is also mass effect on other abdominal structures, most prominently on the liver and pancreas which are displaced medially and the kidney which is displaced posteriorly.
• The mass is made up of locules separated by septations, with the individual locules containing fluid material of varying density. There are a few soft tissue components at the walls peripherally.
• The septae and soft tissue components within the mass show enhancement on the post-contrast images.

Pertinent negative findings:

• There are no calcifications in the mass.
• There are no enlarged local / abdominal lymph nodes.
• There are no hepatic parenchymal / bony metastases.

Incidental findings:

• There are two subcentimetric, hypodense, non-enhancing lesions in the liver, representing simple cysts.

The findings represent a neoplastic, multi-locular mass of mixed fluid and solid components arising from the pancreas.

Principal diagnosis:

Macrocystic mucinous cystadenoma of the pancreas.

Differential diagnosis:

• Mucinous cystadenocarcinoma of the pancreas
• Pancreatic pseudocyst (however, there is no history of prior pancreatitis)
• Serous cystadenoma (this usually has a different appearance with microcysts)

Management:

Alert referring physician of findings.

Refer for discussion at hepatobiliary MDT regarding further management / amenability for resection.

Active multiple sclerosis

Findings and interpretation:

• There are innumerable T2 and FLAIR hyperintense white matter lesions with a generalized distribution throughout both cerebral hemispheres in a generalized, fairly symmetrical distribution. They involve the subcortical, deep and periventricular white matter, as well as the internal and external capsules.
• These lesions are also seen in the brainstem, cerebellar peduncles and cerebellar hemispheres. A single lesion is detected in the cervical spinal cord at the level of C3/C4.
• The lesions are most concentrated at the calloso-septal interface, where they have an elliptical shape with an orientation perpendicular to the lateral ventricles.
• A few of the lesions show avid enhancement on the post-contrast sequence, some of which show ring enhancement.

Pertinent negative findings:

• There is no oedema surrounding the lesions.
• The lesions do not show diffusion restriction.

The findings most likely represent a de-myelinating process in the brain. The enhancing lesions represent active de-myelination.

Principal diagnosis:

Multiple sclerosis

Differential diagnosis:

Neurovasculitis (This is unlikely as the distribution of disease is typical of multiple sclerosis)

Small vessel chronic ischemia with leukoariaosis (however, this would not be expected to enhance)

Brain metastases from unknown primary (however, in this case all of the lesions would enhance and show marked peri-lesional oedema)

Management:

Compare with previous imaging if available.

Recommend discussion at neurology MDT with regards to active disease and medical treatment options.

Chronic osteomyelitis

Findings and interpretation:

Radiographs:

• There is a lucent, slightly expansile lesion in the proximal ulnar metaphysis and extending into the epiphysis.
• The lesion is centred on the medulla and shows a wide zone of transition.
• It demonstrates erosion of and extension beyond the cortex. There is new bone formation surrounding the lesion.
• There is a thick, dense and solid appearing periosteal reaction surrounding the lesion.

MRI

• There high PD and low T1 signal within and expansion of the metaphysis of the ulna, causing destruction of the cortex with surrounding new bone formation. The high signal extends through the bone marrow to the mid-diaphysis of the ulna, indicating pronounced extension of marrow oedema.
• The high PD signal extends to the surrounding soft tissues and around the bone, indicating periosteal reaction and oedema in the surrounding tissues.
• The lesion within the ulnar metaphysis shows avid enhancement on the post contrast sequences.
• An adjacent enhancing lymph node is also detected.

Radiography performed after 1 year:

• There is inhomogeneous osteosclerosis and expansion of the ulnar diaphysis and metaphysis, as well as interspersed lucent areas within.

Pertinent negative findings:

• There is no pathological fracture.
• There is no soft tissue mass.
• No abscesses are detected.

The findings represent a moderately aggressive bony process which is mainly inflammatory; the solid periosteal reaction implies chronicity and healing. The follow up radiograph demonstrates the sequelae of chronic infection with bony hypertrophy and multiple sequestrations.

Principal diagnosis:

Acute followed by chronic osteomyelitis.

Differential diagnosis:

• Eosinophilic granuloma (however, the follow up radiograph would not have that appearance)
• Ewing’s sarcoma (however, the follow up radiograph would not have that appearance)

Management:

Alert referring physician of findings.

Recommend discussion at paediatric orthopaedic MDT regarding further management.