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Hello, welcome back to ProScan MRI Online.

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We are going to continue our discussion

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of non-glial CNS tumors.

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This patient is a two-year-old girl with

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right ear pain. On the far left panel,

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we have a T1-weighted non-contrast sequence.

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On the center panel is our T2-weighted image.

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And on the far right panel is our

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coronal post-contrast sequence.

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And as you notice within

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the right sphenoid bone,

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there is a heterogeneous mass with bony

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expansion and remodeling of the sphenoid

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wing on the T2-weighted sequence,

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you can see that the mass has low signal.

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And following contrast administration on the far

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right panel mass has intense enhancement.

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Important things to note about this lesion are

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you can see on the non-contrast panel

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that the lesion has dural thickening.

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And when you look at your far right panel,

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there is intense enhancement of the dura which

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is thickened and the mass actually projects into

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and is indistinguishable from the

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anterior temporal lobe. Now,

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if you notice this mass compared

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to the contralateral side,

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you can see the skeletal muscle on

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the far left side of the patient.

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And then on the far right side where the

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mass is, the muscle has been replaced,

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the bone has expanded and the lesion extends

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through the bone into the middle cranial fossa.

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The fact that this patient is two years old.

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The likely diagnosis is most consistent with

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Rhabdomyosarcoma, Rhabdomyosarcoma.

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Best diagnostic clue is a soft tissue mass with

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variable contrast enhancement. In this case,

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we have intense enhancement,

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bone destruction or remodeling is common,

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not always typical but happens.

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The location for these lesions occur 40% of the

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time in the head and neck in the orbit.

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Parameingeal sites include middle ear

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perinasal sinus, nasopharynx, masticator space,

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tegopatine fossa, and the peripheral space.

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Intracranial extension occurs

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in up to 55% of the time.

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The size can be variable and may present earlier

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in the case of the orbit location,

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secondary to its small space and

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early proptosis and eye pain.

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Rhabdomyosarcoma is the most common

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childhood soft tissue sarcoma.

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It is a malignant neoplasm of striated muscle.

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The most common signs and symptoms are

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variable as I've already alluded to.

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If this lesion happens within the orbit.

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Given its small space,

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the patient develops proptosis and decreased

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vision leading to an earlier diagnosis.

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If it's in the sinonasal area,

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nasal obstruction,

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epistaxis may present late with a soft tissue

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mass. If it's in the temporal bone,

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symptoms typically include periocular

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or external auditory canal symptoms,

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otitis media or cranial nerve seven palsy.

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If these lesions occur in the neck.

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The patient usually presents with mass pain.

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However,

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it rarely involves the airway

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or airway compromise, Rhabdomyosarcoma,

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myosarcoma prognosis is variable and depends

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on the location and the cell type.

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There are many different cell

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types for this lesion.

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As I've described, orbit gives

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you the best prognosis.

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About 80 to 90% disease-free survival.

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Parameingeal involvement is the worst prognosis.

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Treatment typically includes surgical debulking,

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chemotherapy and radiation therapy.

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Pearls for this lesion.

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One thing to note is that these lesions

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do not always have bone destruction,

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enhancing soft tissue mass without bone

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destruction could simulate an infantile hemangioma.

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However, infantile hemangiomas usually happen earlier,

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they are more intensely homogeneously enhancement

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and have intralesional high-flow vessels

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which we do not see in this case,

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flow voids are absent in most sarcomas.

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In summary,

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we have a mass involving skeletal musculature

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destruction and expansion of the bone intral

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involvement with extension into the right middle

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cranial fossa with dural thickening and which is

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indistinguishable from the adjacent brain parenchyma.

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Most consistent with rhabdomyosarcoma.