Peri-ictal pseudoprogression (PIPG) is a rare complication of prior cranial radiation and is thought to be on the same spectrum as SMART syndrome, albeit less severe.
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Epidemiology
Peri-ictal pseudoprogression is encountered in patients who have a remote history (typically >10 years) undergone prior cranial radiotherapy for the treatment of gliomas 1.
Clinical presentation
Patients with peri-ictal pseudoprogression present with frequent focal seizures, often with constant subclinical epileptogenic discharges on EEG 1. Differently from SMART syndrome, peri-ictal pseudoprogression is usually characterized by absence of headeaches and no significant neurological impairment.
Radiographic features
As SMART syndrome, in peri-ictal pseudoprogression signal alterations on MRI do not have a typical vascular distribution.
MRI
This entity is characterized by leptomeningeal and/or cortical enhancement that spares the underlying white matter 1. Diffusion and perfusion features are variable 1.
Treatment and prognosis
Peri-ictal pseudoprogression is typically fully reversible provided seizure activity can be controlled 1.
Differential diagnosis
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similar epidemiology and similar imaging appearances, although cortical enhancement and swelling are more pronounced in SMART syndrome
clinically, SMART syndrome is characterized by headache/migraine and stroke-like deficits 1,2
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tumor progression
white matter usually involved
mass effect
usually not confined to the cortex
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usually occurs within the first year of treatment
usually not confined to the cortex
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usually has a vascular distribution instead