Presentation
Nasopharyngeal carcinoma treated with radiotherapy. Presented with numbness and paresthesia of the back of the neck.
Patient Data
The medulla oblongata, cervicomedullary junction and whole cervical cord are expanded with diffusely T2 hyperintense signal and T1 hypointense signal with evidence of intramedullary heterogeneous ring enhancement at the cervicomedullary junction posteriorly averaging 1.9 cm in length.
Increased T1 and T2 marrow signal of the upper cervical vertebrae, suggestive of radiation-induced fatty marrow replacement.
D1 left-sided vertebral body hemangioma.
C4/5 small right posterolateral disc protrusion indenting the ventral cord with no foraminal compromise.
C5/6 posterior broad-based disc-osteophyte complex, indenting the ventral cord aspect and encroaching upon exit of neural foramina, more on the right side.
Obliteration of the right fossa of Rosenmüller, due to the known nasopharyngeal carcinoma under treatment.
Disappearance of the previously reported cervicomedullary junction posterior aspect lesion.
De novo intramedullary ring-enhancing lesion at the anterior aspect of the pontomedullary junction averaging 0.8 x 0.9 x 1.9 cm in AP, SS and CC dimensions, suggestive of focal radiation encephalomyelitis.
Mild increased width of the cervicomedullary junction and cervical cord with diffuse central zone T2 hyperintense signal and T1 hypointense signal to the level of mid-body of C3 involving the medulla oblongata and extending to the pontomedullary junction, suggestive of radiation-induced cord edema.
Case Discussion
Radiation myelitis (delayed radiation myelopathy) is a rare serious complication of radiotherapy and is often a diagnosis of exclusion 2. To consider such a diagnosis, the affected spinal cord segment must be in the irradiated zone, symptoms must correspond to the involved spinal cord segment and it presents after a latency period of more than six months 1. It is important to recognize, so as not to be mistaken for metastatic intramedullary lesions and other neurological conditions presenting with myelopathy 1.
In our case, the ring-enhancing intramedullary lesion changed its position from the cervicomedullary junction to the medulla oblongata on follow up scan. This could be due to the change in the radiation planes in radiotherapy sessions. Also, the extent of intramedullary high T2 signal of the cervical spinal cord decreased from the whole cervical cord length to C3 level. The girth of the cervical cord returned to near normal, with a currently increased width of the medulla oblongata where the new lesion appears.