【One case per day】Long-term complications after brain radiotherapy: SMART syndrome

Recently, AJNR magazine published the following case report
.
The medical history is as follows:

The patient, a 27-year-old man, was diagnosed with medulloblastoma at age 5 years and underwent hyperfractionated radiotherapy: 36 Gy of cerebrospinal cord radiation and adjuvant chemotherapy
.
The patient remained stable for 22 years, with migraine with loss
of left visual field developed 1 week ago.

Week1.
Current MRI result (1A): FLAIR images show right parietal-temporal gyrus gyrus with abnormal FLAIR signaling and dural thickening
.
MRI (1B) from a year ago showed no cortical signal abnormalities and swelling, with mild dural thickening
.

Week2.
Contrast enhancement level T1WI(2A) shows increased signal in the right temporal cortex swelling area, which does not exclude associated adjacent leptomeningeal enhancement, as no enhancement
was seen on MRI T1WI(2B) a year ago.

Week3.
The horizontal DWI and corresponding ADC plots showed no diffusion restrictions and there was no sinus thrombosis
.

Week4.
Follow-up FLAIR MRI (4A) and contrast enhancement level T1WI(4B) after 6 weeks showed no swelling, signal abnormalities, or enhancement
.

SMART syndrome

SMART: Stroke-like migraine attack
after radiation therapy.

1.
Reversible, recurrent, long-term complications after radiotherapy for brain tumors (average interval of 20 years);

2.
Complex migraine with neurological deficit and early seizures;

3.
The cause is unknown; May be associated with metabolic, neurological, endothelial injury/dysfunction, vascular instability, and vasospasm; In most cases, symptoms resolve after a few weeks, and symptoms rarely persist and high recurrence
.

The main diagnostic basis is:

1.
MR no positive findings (detected 2 to 7 days after symptom onset and disappears after a few weeks);

2.
Typical in the temporoparietal occipital lobe: transient unilateral gyrus-like T2 abnormal signal, FLAIR signal with mild mass effect, minimal leptomeningeal cortex enhancement signal;

3.
Cortical necrosis
occurs in some cases.

Differential diagnosis:

Recurrence of tumors; prolonged seizures; Subacute cerebral infarction; Venous thrombosis; Radiation causes vascular lesions; Persistent complex migraine; hemiplegic migraine; Reversible posterior encephalopathy syndrome (PRES); mitochondrial encephalomyopathy, lactic acidosis, similar to a stroke attack (MELAS); Meningoencephalitis; Vasculitis; Cerebral autosomal dominant arterial disease is divided into cortical infarction and white matter disease (CADASIL).

Treatment: antiepileptic drugs
.