Is this a benign or aggressive lesion?
Appearances are those of an aggressive process, most likely a malignancy.
What is the differential?
In this age group a Ewing's sarcoma/PNET is the most worrying likely diagnosis.
What does the DWI / ADC appearance suggest?
Restricted diffusion suggests a highly cellular tumour and would be consistent with small round blue cell tumours such as Ewing's sarcoma / PNET.
How can the diagnosis be confirmed?
Imaging guided biopsy. Ultrasound or CT.
A large soft tissue mass measuring three .8th by 5.3 x 4 .4 cm is located on the right side of the neck, the epicenter centred on the transverse process of the C1 vertebra which it destroys. Further patchy destructive bony changes demonstrated within the lateral mass of C1 on the right - it has an aggressive permeative appearance - and is associated with a pathological fracture which extends through the foramen transversarium. The right vertebral artery is displaced medially by the mass, which involves the foramen transverse variant, and appears extrinsic be compressed but not occluded. There is no evidence of epidural extension.
The mass is somewhat heterogeneous, but appears of mostly solid, with no matrix calcification, no periosteal reaction, no convincing cystic component. Although the mass does abut the base of skull superiorly and the transverse process of C2 inferiorly, there are no destructive bony changes at either site.
A number of lymph nodes are slightly prominent, but these are symmetric, and in a patient of this age within normal limits. The remainder of the scan is unremarkable, with no other bony lesions identified. The apices of the lungs appear normal. The portions of the brain which have been imaged (up to the level of the foramen of Monro) appear unremarkable.