Tumefactive Demyelination (TD) is an uncommon demyelinating disorder that may be an intermediate condition between (and sometimes overlapping with) multiple sclerosis and acute demylinating encephalomyelitis.


The lesion in Tumefactive Demyelination is a large (> 2 cm in diameter) focus of demyelination that may clinically and radiologically mimic a brain tumor.


A patient with TD may have 1 or several similar lesions.


The patient may experience:

(1) an upper motor neuron syndrome with weakness in extremities

(2) a change in behavior

(3) seizures

(4) optic neuritis

(5) headaches

(6) vomiting


Conditions that may be associated with tumefactive demyelination:

(1) multiple sclerosis

(2) HIV disease

(3) postinfectious or post-vaccination encephalomyelitis

(4) paraneoplastic

(5) idiopathic


A brain biopsy may show:

(1) extensive loss of myelin with foamy macrophages

(2) sparing of axons

(3) marked perivenular inflammation

(4) mitotically active, bizarre astrocytes (pseudo-gliomatous reaction)

(5) clear border between zone of demyelination and adjacent normal tissue


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