Hemangioendothelioma-CT

3 month old male child came with clinically enlarged nodular palpable liver. CT scan shows enlarged liver with multiple peripherally enhancing variable sized nodular lesion seen occupying whole of the liver in both the lobes. Infra renal part of aorta is small in caliber (arrow head) with dilated and prominant celiac axis (not shown here). There is also similar lesion seen in the upper back subcutaneous region on right side. Features suggestive of hemangioendothelioma.

Discussion:

Benign hemangioendothelioma is a rare liver neoplasm, however it represents the most common vascular tumor of the liver in the neonate. 

The neonatal clinical presentation of hemangioendothelioma includes: 

1) gross liver enlargement, 

2) high-output cardiac failure, and 

3) associated hemangiomas in other organs including skin (hemangiomatosis).

Other complications include consumptive coagulopathy, hemolytic anemia, tumor rupture, and problematic surgical intervention. Hemangioendotheliomas have been recognized on obstetric ultrasound. Neonatal CT, repeat sonography, MRI imaging, and arteriography have all been utilized to visualize the tumor and assess it's size, location, and the anatomy of arterio-venous malformation (AVM) in the neonate. 

The antenatal ultrasound features of hemangioendothelioma include: liver mass (heterogeneous, hypoechoic, complex with anechoic spaces, and hyperechoic), consequent liver enlargement, prominent vasculature, cardiomegaly, and possible hydrops (serous effusions and body edema).Color and pulsed Doppler interrogation can also be particularly useful in identifying an AVM.Post natal findings are liver enlargement, multiple or single confluent liver masses showing peripheral enhancement, may find AV malformation. Typically the celiac axis will be dilated and reduced caliber of infra renal aorta. May find extrahepatic hemangioendothelioma.

Neurocysticercosis starry sky appearance - MRI

Contrast enhanced T1 weighted axial image showing multiple nodular and ring enhancing lesions in bilateral cerebral hemispheres giving starry sky appearance.

Contrast enhanced T1 weighted coronal image showing multiple nodular and ring enhancing lesions in bilateral cerebral hemispheres.

Colloid cyst - MRI

Axial non enhanced T1 magnetic resonance image showing a bright mass in the roof of third ventricle (foramen of Monro).

Axial non enhanced T2 magnetic resonance image showing a hypointense mass in the roof of third ventricle.

Sagittal non enhanced T1-weighted magnetic resonance image. This image demonstrates a round area of increased signal intensity lesion in the anterosuperior portion of the third ventricle.

Discussion:

Colloid cysts are benign, congenital epithelium-lined cysts that almost always arise in the anterior third entricle. However, rare reports describe cysts in other locations. The cysts are believed to derive from either primitive neuroepithelium of the tela choroidea or from endoderm.
Patient may present with intermittent head ache. Rarely may cause sudden death .

CT scan:

• Rounded small mass with high attenuation at the anterior third ventricle - due to proteinacious material.
• Rarely the lesion is isoattenuating or hypoattenuating relative to brain parenchyma.
• Intermittent hydrocephalus - colloid cyst act as ball valve.

MRI:

• Usually found at the foramen of Monro just posterior to the fornices in the anterosuperior third ventricle.
• MR signal intensities are variable: Variation due to contents of the cyst.
• Commonly hyperintense on T1 and iso to hypointense on T2.
• Colloid cysts do not have intrinsic enhancement; the presence of enhancement suggests a solid tumor. Peripheral enhancement may be present because of vascularity in the outer wall.

Traumatic AVN of Scaphoid

PA radiograph of the wrist with scaphoid deviation shows a fracture of the waist of the scaphoid bone (arrow) with loss of trabecular pattern in the distal fragment.

T1 weighted images of the same patient 3 months after trauma showing hypointensity in the distal fractured fragment consistent with avascular necrosis.

Discussion:

Scaphoid fractures are the most common carpal fractures, resulting from a fall on an outstretched hand. 70 % of these occur at the waist, 20 % at the proximal pole, and 10 % at the distal pole. Blood supply for the proximal pole enters at the waist. If this blood supply is interrupted due to fracture, the proximal pole is at risk for avascular necrosis unlike out case where the distal fragment is involved. Special scaphoid views with the hand in ulnar deviation may be needed to detect these fractures.

Avascular necrosis

• More common in scaphoid because of peculiar blood supply
• Up to 30% of scaphoid fractures may display increased density of the proximal pole
• Often reversible
• May be due to relative ischemia of proximal pole
• Occurs in 15-30% of scaphoid fractures
• Almost always involves proximal pole
• The more proximal is the fracture line, the risks of avascular necrosis increase
• The radiographic hallmarks of AVN are collapse and fragmentation
• MRI may be more sensitive to AVN than conventional radiographs but is not 100% sensitive.

Ivory Osteoma

Coronal CT paranasal sinuses showing well defined rounded hyperdense focus seen in the right ethmoid air cell suggestive of ivory osteoma

All the sinuses shows soft tissue opacification including the nasal cavity due to allergic fungal rhinosinusitis.

Axial CT section showing the Ivory osteoma in the posterior ethmoid air cell

Discussion:

Most common tumor of the paranasal sinuses and frequently seen in the frontal and ethmoid sinuses. It is benign tumor of membranous bone consisting of dense, compact bone and majority of of them are discovered serendipitously.
In the skull, they usually arise from the outer table. Rarely, large osteoma in the frontal or ethmoid region may displace globe forward and cause proptosis.
Obstruction of a sinus ostium may lead to infection or formation of a mucocele. Very rarely, an osteoma may erode through the dura leading to cerebrospinal fluid rhinorrhea or intracranial infection.

Imaging findings:

Well-circumscribed, sharply-marginated round and very dense lesions usually less than 2 cm in size. Multiple paranasal osteomas are found in Gardner’s syndrome.
Multiple osteoma of the mandible and maxilla, along with the frontal, sphenoid and ethmoid sinuses, rarely the long bones or phalanges
Association between colonic polyps with a predilection to malignant degeneration.

Traumatic fracture of terminal phalynx

Traumatic fracture in the base of the terminal phalynx (arrow).

Healed Varicella Pneumonia

There are multiple tiny subcentimeter calcific densities noted throughout both lung parenchyma more on the left side. There is no focal lung parenchymal mass or cavitating lesion seen. The appearances are classical for previous varicella exposure. 

Reference: 

Kim EA, et al. Viral Pneumonias in Adults: Radiologic and Pathologic Findings. RadioGraphics 2002; 22: 137.Credit: Dr Abhijit Datir

Lateral epicondyle bursitis

Coronal STIR image shows focal hyperintense signal (fluid signal) in the region of lateral epicondylar bursa suggestive of bursitis. No evidence of altered marrow signal intensities.

 Axial T2 fat suppressed image showing fluid collection in bursa.

Sagittal image showing the hyperintensities.

Discussion:

The inflammation of the lateral epicondyle bursa which should not be mistaken for the lateral epicondylitis/tennis elbow.

Lateral epicondylitis, colloquially refereed to as “tennis elbow“ presents as pain and tenderness over the common extensor tendon insertion on the lateral epicondyle elicited by active supination of the forearm and dorsiflexion of the wrist.

The MRI appearance of lateral epicondylitis is thickening and/or increased signal intensity in the common extensor tendon can be seen on T2-weighted spin echo, T2*-weighted gradient-echo or STIR images in the coronal plane. Fat-suppressed Fast spin-echo sequences are particularly useful. The underlying bone marrow may show changes.

The MRI appearance of the lateral epicondyle bursitis is variable fluid collection within the bursa. No marrow altered signal intensity seen.

Diaphyseal Aclasis-Hereditary multiple exostoses

Radiograph of left knee AP and lateral views showing multiple bony out growth seen in the metadiaphyseal region growing away from the epiphysis in femur, tibia and fibula.

Radiograph of another patient of bilateral knee AP views showing multiple bony out growth in the metadiaphyseal region growing away from the epiphysis in femur, tibia and fibula.

Discussion: Diaphyseal Aclasis is also known as:

1. External Chondromatosis Syndrome
2. Multiple Cartilaginous Exostoses
3. Multiple Exostoses
4. Multiple Exostoses Syndrome
5. Multiple Osteochondromatosis

Diaphyseal Aclasis isa relatively rare abnormal condition that affects the skeletal system. Characterized by multiple exostoses or bony protrusions, it is inherited as a dominant trait. Approximately half of the children of an individual with diaphyseal aclasis display varying degrees of its symptoms.Evident involvement is diffuse, with the long bones usually affected more severely and more frequently than the short bones. The malignant change is more frequent compared to the solitary exostosis.

Signs of malignant development refer my other post on Chondrosarcoma in osteochondroma -

http://manju-imagingxpert.blogspot.com/2011/06/secondary-chondrosarcoma-from.html

Lipoma of the Filum Terminale

T1 sagittal image of the lumbar spine showing multiple osteoporotic collapsed vertebral bodies with elongated linier  wavy hyperintense intraspinal structure from the level of L2 to S1 consistent with filum terminale lipoma.

Axial T1 weighted image showing filum terminale lipoma as small intraspinal hyperintense dot (arrow).

Discussion:

Fat in the filum terminale is not an infrequent occurence, seen in 4 – 6%, and is usually easily detected on MRI (especially T1 sequences). It is usually an incidental finding of no clinical concern.
In some individuals however it is associated with spinal dysraphism, thickening of the filum terminale (>3mm) and tethering of the spinal cord.
Classification: Four patterns: 

1) fatty filum with descended conus medullaris and symptoms.

2) fatty filum with descended conus medullaris and no symptoms.

3) fatty filum with normal conus medullaris position and symptoms.

4) fatty filum with normal conus medullaris position and no symptoms

Imaging findings:

CT scan: If the lesion is large, seen as hypodense focus (fat density HU -90 to -30) below the level of conus. If it is  small may not be visible.

MRI: is modality of choice.

• Hyperintense on T1 and T2 FSE
• Saturates on fat saturation sequences
• Demonstrates chemical shift artefact
• No enhancement.

References
1. E Brown et al “Prevalence of incidental intraspinal lipoma of the lumbosacral spine as determined by MRI.” Spine. 1994 Apr 1;19(7):833-6.
2. K Koeller et al “Neoplasms of the Spinal Cord and Filum Terminale: Radiologic-Pathologic Correlation” RadioGraphics 2000; 20: 1721-1749.