Spinal Mass



Spinal Mass


Anne Kennedy, MD



DIFFERENTIAL DIAGNOSIS


Common



  • Myelomeningocele


  • Myeloschisis


  • Sacrococcygeal Teratoma


Less Common



  • Lipoma/Lipomyelomeningocele


  • Lymphangioma


  • Myelocystocele


Rare but Important



  • Iniencephaly


  • Chiari III Malformation


ESSENTIAL INFORMATION


Key Differential Diagnosis Issues



  • Multicystic mass in region of distal spine



    • Differentiate myelomeningocele from sacrococcygeal teratoma due to prognostic implications


    • Myelomeningocele



      • Prognosis depends on associated malformations and level of defect


      • Amniocentesis offered as associated with aneuploidy


      • Not associated with high output state


    • Sacrococcygeal teratoma (SCGT)



      • Prognosis depends on size, intrapelvic extension, growth rate and vascularity


      • Solid rapidly growing SCGT → high output state → hydrops


      • Fetal therapy indicated for impending hydrops


      • Multicystic lesions have good prognosis


  • Maternal history important



    • Valproate embryopathy


    • Diabetic embryopathy


  • Differential diagnosis of patient with elevated maternal serum alpha fetoprotein (msAFP)



    • “Open anything”


    • Myelomeningocele important diagnosis as potential to decrease recurrence risk in future pregnancies


Helpful Clues for Common Diagnoses



  • Myelomeningocele



    • Elevated msAFP


    • Associated with Chiari II brain malformation in 99% of cases



      • Obliteration of cisterna magna


      • “Banana” shaped cerebellum


      • Ventriculomegaly/hydrocephalus


      • “Lemon-shaped” head (bifrontal concavity which resolves in third trimester)


    • Open neural tube defect



      • Posterior elements splayed or divergent: Lack of normal “teepee” shape on axial view


      • Parallel posterior elements abnormal if reproducible from different scan planes


  • Myeloschisis



    • Open defect with no covering membrane


    • Neural placode exposed to amniotic fluid


    • Everted edges may appear as spinal mass


  • Sacrococcygeal Teratoma



    • Cystic, solid, or mixed echogenicity mass arising from sacrum



      • Purely cystic in 15%


      • May contain calcifications


    • Posterior elements intact


    • Sacrum present


    • Solid lesions may be hypervascular putting fetus at risk for developing hydrops


    • Grading system developed by American Academy of Pediatric Surgery Section



      • Type 1: Completely external or minimal presacral component


      • Type 2: External and internal component extending into presacral space


      • Type 3: External and internal component extending into abdomen


      • Type 4: Completely internal, no external component


    • Brain is structurally normal


Helpful Clues for Less Common Diagnoses



  • Lipoma/Lipomyelomeningocele



    • Skin covered defect


    • Not associated with elevated msAFP


    • Subcutaneous mass of variable echogenicity


    • Lipoma: No spinal canal enlargement


    • Lipomyelomeningocele: Tethered low-lying spinal cord inserts into lipoma through dysraphic defect


  • Lymphangioma



    • Multicystic mass


    • May be anywhere along torso


    • Skin-covered



    • May mimic myelomeningocele or cystic sacrococcygeal teratoma



      • Myelomeningocele associated with open neural tube defect; sac extends out of spine defect


      • Sacrococcygeal teratoma arises from sacrum


  • Myelocystocele



    • Skin-covered lumbosacral dysraphism


    • Hydromyelic cord traverses meningocele, expands into large contiguous terminal cyst


    • Abnormal cystic dilatation of thecal sac (i.e., intradural)



      • All other cystic spinal masses arise in soft tissues


    • May be associated with other abnormalities



      • Caudal regression or OEIS syndrome (omphalocele, exstrophy of the bladder, imperforate anus, and spinal anomalies)


Helpful Clues for Rare Diagnoses



  • Iniencephaly



    • Lethal open neural tube defect


    • High cervical location, spinal defect may extend to thoracic/lumbar area (rachischisis)


    • Cervical vertebrae are missing or fused


    • Associated occipital encephalocele


    • Associated with fixed hyperextension of neck → “stargazer” fetus


    • Mandibular skin contiguous with chest


  • Chiari III Malformation



    • Intracranial findings of Chiari II


    • High cervical ± low occipital osseous defect


    • Herniation of posterior fossa contents (i.e., cerebellum, brain stem, fourth ventricle ± upper cervical spinal cord) through osseous defect


Other Essential Information

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Aug 10, 2016 | Posted by in OBSTETRICS | Comments Off on Spinal Mass

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