Lumbar Soft Tissue Mass, Pediatric



Lumbar Soft Tissue Mass, Pediatric


Kevin R. Moore, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Lipomyelomeningocele


  • Myelomeningocele


  • Lipoma, Spinal


  • Spinal Muscle Injury, Traumatic


  • Scoliosis


Less Common



  • Plexiform Neurofibroma


  • Ewing Sarcoma


  • Lymphoma


  • Venous Vascular Malformation


  • Lymphatic Malformation


  • Abscess, Paraspinal


Rare but Important



  • Metastases, Lytic Osseous


  • Hemangiopericytoma


  • Meningocele, Dorsal Spinal


  • Pseudomeningocele


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Appearance of overlying skin, pertinent clinical information helps limit differential list


Helpful Clues for Common Diagnoses



  • Lipomyelomeningocele



    • Lipomyelocele = neural placode-lipoma complex contiguous with subcutaneous fat through dysraphic defect, attaching to and tethering spinal cord


    • Lipomyelomeningocele = lipomyelocele + meningocele, enlargement of subarachnoid space, displacement of neural placode outside of spinal canal


  • Myelomeningocele



    • Posterior spinal defect lacking skin covering ⇒ neural tissue, CSF, and meninges exposed to air


    • Lumbosacral (44%) > thoracolumbar (32%) > lumbar (22%) > thoracic (2%)


    • Low-lying cord on post-operative MR imaging does not always = clinical tethering


  • Lipoma, Spinal



    • Arise from premature separation (dysjunction) of cutaneous ectoderm from neuroectoderm during neurulation


    • Profound hypodensity on CT and T1WI hyperintensity characteristic of fat


    • Use chemical fat saturation or inversion recovery MR techniques to confirm fat content


  • Spinal Muscle Injury, Traumatic



    • Paraspinal muscle fiber disruption from indirect forces ⇒ abnormal muscle T2 hyperintensity and swelling


    • Most commonly from MVA; also athletic injuries, blow from falling objects, direct injury


  • Scoliosis



    • General term for any lateral curvature of spine



      • Dextroscoliosis: Curve convex to right


      • Levoscoliosis: Curve convex to left


      • Kyphoscoliosis: Scoliosis with component of kyphosis


      • Rotoscoliosis: Scoliosis which includes rotation of vertebrae


    • Short-curve scoliosis usually has underlying abnormalities; consider congenital, neoplasm, or inflammation


Helpful Clues for Less Common Diagnoses



  • Plexiform Neurofibroma



    • Long, bulky, multinodular nerve enlargement is pathognomonic for NF1


    • Often affects sacral or brachial plexi


  • Ewing Sarcoma



    • 5% of all Ewing tumors in spine (sacrum > rest of spine)


    • Usually in adolescents or younger adults


    • Permeative lytic lesion of vertebral body or sacrum involving vertebral body before neural arch



      • Contiguous spread along peripheral nerves from spine or sacral primary, but may originate in soft tissues


  • Lymphoma



    • Lymphoreticular neoplasms with wide variety of specific diseases & cellular differentiation


    • Multiple types demonstrate variable imaging manifestations


  • Venous Vascular Malformation



    • Congenital trans-spatial vascular malformation of venous channels present from birth



    • May be mass-like, frequently enhances moderately (less than soft tissue hemangioma)


    • No arterial vessels within lesion, venous channels may be large


    • Look for phleboliths to make specific diagnosis


  • Lymphatic Malformation



    • Congenital trans-spatial vascular malformation of lymphatic channels present from birth


    • Typically minimal to no enhancement, although septations may enhance, especially if previously inflamed


    • Fluid-fluid levels strongly suggest diagnosis


    • May grow rapidly if hemorrhage or concurrent viral infection


  • Abscess, Paraspinal



    • Suppuration of paraspinal soft tissue from direct extension or hematogenous dissemination of pathogens


    • Identification of calcified psoas abscesses suggests tuberculous paraspinal abscess


Helpful Clues for Rare Diagnoses

Aug 7, 2016 | Posted by in NEUROLOGY | Comments Off on Lumbar Soft Tissue Mass, Pediatric

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