An 18-year old man with known neurofibromatosis type 2 (NF2) was admitted to the hospital because of the chance finding of a large retroperitoneal tumor on a magnetic resonance image. Clinical examination found a slight paresis of the plantar extension of the left foot. Magnetic resonance imaging (Figure, A and B) showed a smoothly delimited, nonhomogeneous intraforaminal mass exiting the vertebrae between the L2 and L3 intravertebral space, extending (14 × 6.5 × 7.3 cm3) paravertebrally to the left from L1 to L4/L5, lying on the psoas muscle, compressing the left kidney, and causing obvious retention signs. Several other smaller intraforaminal tumors were also described. Positron emission tomography (PET) and computed tomography (CT) were performed using a combined PET/CT scanner (Discovery LS; GE Medical Systems, Solingen, Germany). Emission data were acquired 60 minutes after 1.06 × 10−11 Ci (392 mBq) of fludeoxyglucose F 18 (FDG) injection and 12 hours of fasting. Results showed nonhomogeneous uptake of the tracer within the large tumoral mass but not in the smaller neuroforaminal tumors. The complete mass was extirpated because the possibility of malignancy could not be excluded. At examination the strictly encapsulated tumor was found to encompass the first 3 lumbar radices; no organ infiltration was described. The postoperative course was bland. Histologic examination revealed the classic features of a benign cellular schwannoma.
Hanemann CO, Kaempchen KE, Kaufmann D, Krause BJ. Fludeoxyglucose F 18 Positron Emission Tomography and Computed Tomography of a Giant Retroperitoneal Schwannoma Occurring in a Patient With Neurofibromatosis Type 2. Arch Neurol. 2005;62(4):674-675. doi:10.1001/archneur.62.4.674