Lumbar Soft Tissue Mass

Lumbar Soft Tissue Mass
Kevin R. Moore, MD
DIFFERENTIAL DIAGNOSIS
Common
  • Lipomyelomeningocele
  • Myelomeningocele
  • Spinal Lipoma
  • Traumatic Spinal Muscle Injury
  • Scoliosis
Less Common
  • Plexiform Neurofibroma
  • Ewing Sarcoma
  • Lymphoma
  • Venous Vascular Malformation
  • Lymphatic Malformation
  • Paraspinal Abscess
Rare but Important
  • Lytic Osseous Metastases
  • Hemangiopericytoma
  • Dorsal Spinal Meningocele
  • 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 image neural tissue, CSF, and meninges exposed to air
    • Lumbosacral (44%) > thoracolumbar (32%) > lumbar (22%) > thoracic (2%)
    • Low-lying cord on postoperative MR imaging does not always = clinical tethering
  • Spinal Lipoma
    • 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
  • Traumatic Spinal Muscle Injury
    • Paraspinal muscle fiber disruption from indirect forces image 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 and 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
Aug 10, 2016 | Posted by in PEDIATRICS | Comments Off on Lumbar Soft Tissue Mass

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