Reason: Disease progression History: schwannomatosis and bone lesions Please note that comparison to the prior examination is suboptimal due to technical differences between the protocols.Pelvis:Several small foci of signal abnormality are identified within the bones of the pelvis bilaterally. The reference lesion(s) seen on the prior study, presumably within the right ilium posteriorly, appears less confluent on the current study than on the prior study. For future reference purposes, a ring-enhancing lesion within the right ilium, lateral to the right sacroiliac joint, measures approximately 1.4 cm in its greatest transverse diameter. There is low signal intensity within the left ilium, posteriorly, which may represent a site of prior surgical biopsy with adjacent foci of metallic susceptibility artifact in the overlying soft tissues. There are small foci of abnormal signal intensity and enhancement also noted within the proximal femoral, bilaterally. Mild osteoarthritis affects both hips. Mild osteoarthritis affects the sacroiliac joints. Degenerative disc disease affects the lower lumbar spine. There is a fluid collection with thin peripheral enhancement within the lateral subcutaneous fat of the right hip, measuring approximately 4 cm in the craniocaudal dimension, perhaps representing a seroma from prior surgery. There is a small minimally enhancing mass along the S2 nerve root which may represent a small schwannoma. There is an ovoid mass measuring approximately 1 cm within the vastus lateralis muscle on the left which may also represent a peripheral nerve sheath tumor.Right femur:There is poorly defined intermediate signal intensity within the femoral diaphysis which may simply represent red marrow. There are small subcentimeter schwannomas in the right sciatic nerve within the proximal thigh and also in the distal thigh which measures approximately 1.3 cm in its greatest diameter. There is an additional schwannoma within the vastus lateralis measuring approximately 1.2 cm in its greatest diameter. There is a small amount of fluid within the knee joint.
1. Multiple small marrow-based lesions within the pelvis and proximal femora, as described above, of uncertain etiology.2. Multiple small nerve sheath tumors as described above.