28-year-old male with NF1 and extensive sacral and pelvic disease. Please delineate the margins of the plexiform neurofibromas in his pelvis. There are innumerable masses of low signal intensity on T1-weighted images and high signal intensity on STIR images, many having a target appearance, within the skin, subcutaneous and deep soft tissues of the pelvis compatible with nerve sheath tumors and the stated history of neurofibromatosis type I. Plexiform neurofibromas involve the lumbar and sacral nerve roots as well as both sciatic nerves, extending off the field-of-view of this study. There are also plexiform neurofibromas involving both femoral nerves, slightly prominent on the right. Additional neurofibromas are noted within the pelvis as well as the surrounding musculature but we see no single dominant lesion to suggest malignancy. Bone marrow signal intensity is within normal limits. The hip joints, sacroiliac joints and pubic symphysis are unremarkable.
Findings compatible with neurofibromatosis with plexiform neurofibromas as above.