Types of Myelodysplasia

Question 1

Myelodysplasia

Answer 1

defective development of any part (especially lower segments) of the spinal core

individuals are at risk of further LOF over time, paralysis may occur later in life as a complication of abnormal tissue growth causing pressure on nerves

Question 2

Aperta

Answer 2

Aperta- open or visible

Myelomenignocele = open spinal cord defect that usually protrudes dorsally, not skin covered, usually associated with nerve paralysis
- meninges and nerves can also protrude anteriorly and laterally– not visible externally but associated with nerve paralysis– not all have this associated paralysis

Meningoceles- skin covered and initially associated with no paralysis, contain only membranes or nonfunctional nerves that end in the sac wall

Question 3

Occulta

Answer 3

Occulta- hidden or not visible

Lipoma of the spinal cord- most are visible, may be large or small, manifest as distinct subcut masses frequently associated with pigmentation of the skin, hirusutism (hairy patch), skin appendages or dimples in gluteal cleft

• lipomatous or fibrous tract descend ventrally from lipoma to varying extents of the subdural space adjacent to the spinal cord
• -Classified based on level of SC
  1. lipomyelomenigocele with paralysis
  2. lipmenigocele without paralysis
  3. lipas of filum terminale usually without paralysis
  4. lipads of cauda equina or conus medullaris with or without paralysis at birth
• – paralysis absent at birth is often acquired over time, if present at birth will worsen over time

Some lipomas not associated with extension to subcut
May be associated with bifid vertebrae

Question 4

Diastematomyelia

Answer 4

fibrous, cartilaginous, or bony band or spicule separating the SC into hemicords each surrounded by a dural sac

—splits spinal cord

Can occur as an isolated defect or in conjunction with myelomeningocele or lipomyelomeningocele

Depending on associated involvement may be associated with paralysis initially or progressive weakness over time developed in occulta lesion due to cord tethering

Question 5

Myelocystoceles

Answer 5

least common, septated or separate cysts
- separate from the central canal of the SC and from the subarachnoid space

occur in low lumbar and sacral area and are skin covered

may or may not be associated with nerve impairment or lipomas of the SC

When associated with a primitive gut and open abdomen = classified as exstropy of the cloaca

Missing or abnormal segments of sacrum = myelocystic lesion termed sacral agenesis