DX: Schwannoma of the upper limb (preliminary)

This is the conslusion of the case. Patient underwent MR because of  US findings consistent with a heterogeneous hypoecoic mass with partial vascularity, sharp edges, within triceps  and biceps brachii muscles along the median or ulnar nerve in the medial plane of the upper arm.  Long axis shows that it presumptively comes from neural origin because fibers attached in cephalic and caudal position of the mass.

MR shows displacement of brachial artery and vein so neural origin has to come in consideration. It is moderate iso-hyperintense on T1 with moderate Gd-DTPA uptake.

Here are some pictures I' ve found on a quick websearch (I do not own this pictures):




http://www.ultrasoundcases.info/Slide-View.aspx?cat=438&case=1966

http://www.jortho.org/2007/4/2/e37/index.htm

 Schwannoma, also known as neurilemmoma, is a benign soft tissue tumour arising from the schwann cells of the nerve sheath. Schwannomas are usually solitary and encapsulated.

Is one of the few truly encapsulated neoplasms of the human body and is almost always solitary. It’s most common locations are the flexor surfaces of the extremities, neck, mediastinum, posterior spinal roots, and cerebellopontine angle. The nerve of origin often can be demonstrated in the periphery, flattened along the capsule but not penetrating the substance of the tumor. Since this is a benign neoplasm every attempt should be made to preserve the nerve.

The Schwannoma (neurilemmoma) is the most common tumor of the peripheral nerve, it accounts for 8% of all primary intracranial tumors and 80-90% of those in the cerebellopontine angle. The peak incidence is in the third to sixth decades, with a slight female predominance. Intracranially there is a predilection for sensory nerves especially the vestibular branch of the eighth nerve. Rarely, schwannomas occur intraparenchymally within the brain, cerebellum, or spinal cord: in such rare instances, they presumably arise from schwann cells that accompany blood vessels.

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This was an outpatient and was reffered to a Peds Surgeon in other hospital.