Limbus Vertebra

LS spine x-ray, sagittal-reformatted CT and sagittal T1W MR images demonstrate a limbus vertebra in the anterosuperior corner of L4 vertebral body in this 32-year-old woman.

Facts

• Intrabody herniation of disc material at the margin of the endplate, occurs during spinal growth before skeletal maturity
• Herniation of nuclear material through the cartilaginous junction zone of ring apophysis may isolate this ossification center from the body margin, inhibiting osseous fusion to the vertebral body
• Up to 5% of cadavers
• Generally asymptomatic

Imaging

• Smoothly corticated triangular fragment of bone at the corner of the vertebral body
• Most common in midlumbar spine (L2-4) but can be at any level including cervical spine
• Most common at the anterosuperior corner of the vertebral body
• Typically displaced farther from margin of vertebral body

References:

Ghelman B, Freiberger RH. The limbus vertebra: an anterior disc hernation demonstrated by discography. AJR 1976; 127:854-855

Atypical Hepatic Hemangioma - Echoic Border

Ultrasound images of the liver show a round hypoechoic nodule (arrow, calipers) in the right lobe with an echoic border. Background fatty liver is noted. 

Hemangioma with Echoic Border

• Frequent atypical pattern at ultrasound
• Can have either thick echoic rind or thin echoic rim
• Internal echo is at least partially hypoechoic, which is assumed to represent previous hemorrhage, necrosis, scarring or myxomatous change

Reference:

Vilgrain V, et al. Imaging of atypical hemangiomas of the liver with pathologic correlation. Radiographics 2000; 20:379.

Extraosseous Myeloma

Axial PET/CT images show a large homogeneous soft tissue mass in the lett buttock involving the gluteal muscles, which demonstrates significant FDG avidity. 

Extraosseous Myeloma

• 10-16% of patients with multiple myeloma
• Rising incidence possibly due to better imaging techniques and increased survival of patients with myeloma
• More common in younger myeloma patients and more aggressive subtypes
• Shorter survival and shorter progression-free survival (than patients without extraosseous involvement)
• Has been integrated into an updated version of Durie-Salmon staging system

How to Image Patients with Myeloma

• Skeletal survey (current minimum standard)
• Whole-body PET/CT vs. whole-body MRI for newly diagnosed myeloma and with no findings or limited findings on skeletal survey (two different methods have been suggested by different authorities) to assess for occult involvement

Imaging Appearances

• Soft tissue: nodules in subcutaneous tissues and muscles (like in our case)
• Reticuloendothelial system: lymph node enlargement in multiple stations
• Liver: hepatomegaly, low-attenuation liver lesions without enhancement
• CNS: leptomengineal process 
• Lungs: lung nodules, masses, interstitial infiltration
• Kidneys: masses, diffuse enlargement
• Peritoneum: masses

Reference:

Hall MN, Jagannathan JP, Ramaiya NH, et al. Imaging of extraosseous myeloma: CT, PET/CT and MRI features. AJR 2010; 195:1057-1065. 

Happy New Year 2013!