Schwannomatosis, marrow abnormalities Several foci of signal abnormality are again identified within the bones of the pelvis bilaterally. The reference lesion in the right ilium lateral to the sacroiliac joint seen on the prior study now shows more homogeneous enhancement and signal intensity although is similar in size. Posterior to this referenced lesion is a larger lesion measuring 2.3 x 1.6 cm in the transverse dimension, representing a slight increase in size from the prior exam. This particular lesion demonstrates hypointensity on T1 sequences, hyperintensity on T2 sequences, and minimal enhancement following gadolinium administration. Several remaining smaller lesions within the right ilium appear similar to the prior examination with lesions in the left ilium appearing similar or slightly smaller than the prior study. Obturator ring lesions also appear similar to the prior exam while some lesions within the proximal femora appear slightly smaller.Mild osteoarthritis affects the hips and sacroiliac joints and degenerative disc disease affects the lower lumbar spine. The previously described fluid collection lateral to the right hip is no longer present.A lesion within the left piriformis muscle at the level of S2 is unchanged. A small, minimally enhancing lesion along the anterior aspect of the left iliopsoas muscle is unchanged and may represent a small schwannoma.
Multifocal marrow abnormalities involving the pelvis and proximal femora showing a mixed response with a reference lesion in the right ilium appearing more conspicuous while several lesions throughout the remaining pelvis and proximal femora appear slightly smaller.