Peri-ictal pseudoprogression

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. 

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

• SMART syndrome

  • 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 

• tumor progression

  • white matter usually involved

  • mass effect

  • usually not confined to the cortex

• tumor pseudoprogression

  • usually occurs within the first year of treatment

  • usually not confined to the cortex

• subacute stroke

  • usually has a vascular distribution instead