CEREBRAL HAMMARTOMATOUS CEREBRAL HAMMARTOMATOUS (SPONGIOTIC) LESIONS(SPONGIOTIC) LESIONS

IN CHILDREN WITH NF – I: A IN CHILDREN WITH NF – I: A PICTORIAL ESSAYPICTORIAL ESSAY

H. S. Das, MDH. S. Das, MD MATRIXMATRIX

Guwahati-5, Assam, IndiaGuwahati-5, Assam, India

Propose of studyPropose of study

To present the characteristic MRI and To present the characteristic MRI and cutaneous findings of cerebral non- cutaneous findings of cerebral non- neoplastic hammartomatous lesions in neoplastic hammartomatous lesions in clinically diagnosed children with NF - Iclinically diagnosed children with NF - I

Study MethodStudy Method

Seven Seven clinically diagnosedclinically diagnosed children with NF – I children with NF – I undertaken on an open 0.2 tesla MR system. undertaken on an open 0.2 tesla MR system.

to evaluate presence and extent of to evaluate presence and extent of intracranial lesions associated with NF-Iintracranial lesions associated with NF-I

Standard MR sequences obtained. No IV Standard MR sequences obtained. No IV contrast was usedcontrast was used..

Results-1Results-1 N=7. Four patients showed the above typical N=7. Four patients showed the above typical

features. Findings of the other three children features. Findings of the other three children were non-specific & excluded from study. were non-specific & excluded from study.

Age = 8 - 10 years (mean = 9.2 years) Age = 8 - 10 years (mean = 9.2 years)

Sex = 2:2 Sex = 2:2

No familial history / macrocephalyNo familial history / macrocephaly

Some form of cutaneous stigmata of NF –I Some form of cutaneous stigmata of NF –I (multiple café-au-lait spots, iris hamartomas, (multiple café-au-lait spots, iris hamartomas, lisch nodules, axillary freckling etc) were lisch nodules, axillary freckling etc) were present in all casespresent in all cases

All four patients exhibited Focal Areas of Signal All four patients exhibited Focal Areas of Signal Increase on T2WI (FASI) Increase on T2WI (FASI)

Results-2Results-2 Medial globus pallidi, ventral midbrain and Medial globus pallidi, ventral midbrain and

middle cerebellar peduncles involved in middle cerebellar peduncles involved in bilaterally symmetrical manner. bilaterally symmetrical manner.

Isolated scattered FASI also noted in Isolated scattered FASI also noted in hippocampi, pons and cerebellum in all the hippocampi, pons and cerebellum in all the four cases. four cases.

The lesions were iso to hypointense on T1 WI. The lesions were iso to hypointense on T1 WI.

Characteristic lack of mass effect for which Characteristic lack of mass effect for which contrast administration was withheld. contrast administration was withheld.

No other known intracranial lesion associated No other known intracranial lesion associated with NF-I was seen in the four children. with NF-I was seen in the four children.

ConclusionsConclusions

FASI seen in approx. 50% children with NF-I in the basal FASI seen in approx. 50% children with NF-I in the basal ganglia, thalamus, corpus callosum and brainstem.ganglia, thalamus, corpus callosum and brainstem.

Pathologically these lesions are malformative (benign) Pathologically these lesions are malformative (benign) rather than neoplastic and thought to be due to rather than neoplastic and thought to be due to vacuolar (spongiotic) changes of myelin possibly vacuolar (spongiotic) changes of myelin possibly related to intramyelinic edema. related to intramyelinic edema.

Lesions not seen before 18 months of age and reach Lesions not seen before 18 months of age and reach maximum size and intensity at 8 to 10 yrs and then maximum size and intensity at 8 to 10 yrs and then fade through adolescence. fade through adolescence.

Multiple, bilateral and variable signal on T1WI.Multiple, bilateral and variable signal on T1WI.

Lack mass effect and do not show obvious Lack mass effect and do not show obvious enhancement with gadolinium. Lesions exhibiting mass enhancement with gadolinium. Lesions exhibiting mass effect and enhancement are thought to represent low-effect and enhancement are thought to represent low-grade gliomas. grade gliomas.