Intraosseous schwannoma
Updates to Case Attributes
Intraosseous schwannomas are rare, representing <1% of primary bone tumors. They tend to occur in the mandible (arising from the inferior alveolar nerve), however can occur in almost any bone, and tend to occur in or near nutrient canals.
Radiographically, intraosseous schwannomas tend to present with benign, cyst-like features, and on MR they typically show features similar to those seen here, with isointense signal to muscle on T1 and heterogeneously hyperintense T2 signal. As these characteristics are not unique, predicting this histologic entity in the differential diagnosis is difficult, however should at least be considered in appropriate cases.
In the past, this entity has routinely been referred to as an intraosseous neurilemmoma.
Special thanks to Dr. Cristina Costales for the photomicrographs.
-<p>Intraosseous schwannomas are rare, representing <1% of primary bone tumors. They tend to occur in the mandible (arising from the inferior alveolar nerve), however can occur in almost any bone, and tend to occur in or near nutrient canals.</p><p>Radiographically, intraosseous schwannomas tend to present with benign, cyst-like features, and on MR they typically show features similar to those seen here, with isointense signal to muscle on T1 and heterogeneously hyperintense T2 signal. As these characteristics are not unique, predicting this histologic entity in the differential diagnosis is difficult, however should at least be considered in appropriate cases. </p><p>In the past, this entity has routinely been referred to as an intraosseous neurilemmoma.</p>- +<p>Intraosseous schwannomas are rare, representing <1% of primary bone tumors. They tend to occur in the mandible (arising from the inferior alveolar nerve), however can occur in almost any bone, and tend to occur in or near nutrient canals.</p><p>Radiographically, intraosseous schwannomas tend to present with benign, cyst-like features, and on MR they typically show features similar to those seen here, with isointense signal to muscle on T1 and heterogeneously hyperintense T2 signal. As these characteristics are not unique, predicting this histologic entity in the differential diagnosis is difficult, however should at least be considered in appropriate cases. </p><p>In the past, this entity has routinely been referred to as an intraosseous neurilemmoma.</p><p><strong>Special thanks to Dr. Cristina Costales for the photomicrographs. </strong></p>
Updates to Study Attributes
A lobulated lesion is present in the left femoral neck and intertrochanteric region, which is isointense to muscle on T1 and heterogeneously hyperintense on T2/STIR. A portion of this lesion extends beyond the osseous confines of the anterior and lateral femoral neck, up to 1cm, in the region that cortical violation was present on CT. A small amount of fluid-like signal (edema) extends along the adjacent intermuscular fascial planes. A small hip joint effusion is present. All other intraosseous marrow signal is normal, and no satellite lesions or enlarged lymph nodes are identified.
Updates to Study Attributes
Re-demonstration of the findings seen on radiographs, showing a lytic lesion in the left proximal femur, with a well-defined sclerotic rim, but with multiple areas of seversevere cortical thinning and cortical violation, as well as homogeneous soft-tissue attenuation. The fracture line is also well re-demonstratedcharacterized, extending through the remaining portion of the posterior cortex of the femoral neck.