Infantile atypical subependymal giant cell astrocytoma

Abstract

Subependymal giant cell astrocytoma is a benign WHO grade I intraventricular tumor arise in patients with tuberous sclerosis complex. Previous reported described histopathological predictors of more aggressive forms, terms atypical SEGA in infantile age group. Other reports showed possible transformation of SEGA into glioblastoma, or misdiagnosis as glioblastoma due to the presence of atypical histopathological features. Here, we report a case of an infant who presented with right frontal extraventricular SEGA and underwent craniotomy with complete resection. Eight months later, he presented with fast recurrence in same location with midline shift and subfalcine herniation. Histopathological description showed high grade features including Ki labeling index of 60%, atypical mitotic figures, cellular plemorphism and necrosis. We also discussed the possible presence of different entity (termed atypical SEGA) which may have more aggressive clinical course, with literature review of predictors of SEGA aggressiveness and possible transformation/misdiagnosis as glioblastoma.

Figure 1

Showing patient hospital course and outcome after discharge.

Figure 2

Magnetic resonance imaging T1 with gadolinium, showing A) right frontal homogenously enhancing tumor. Notice the other small right periventricular lesion abutting the right frontal horn. B) Post-operative T2 MRI showing complete resection. C) Recurrence after 8 months. CT brain showed right frontal hyerdense lesion with midline shift and subfalcine herniation. There are areas of calcifications and periventricular hyperdense nodules.

Figure 3

Histopathological examination of the initial tumor with atypical features. A) Mild cellular pleomorphism (upper left) adjacent to more monomorphic and spindled glial cells (lower right). Note the bizarre atypical mitotic figure (arrow), (Hematoxylin and Eosin, x200). B) Bizarre tumor giant cells are seen at the lower right and mononuclear cells at the upper left. Two atypical mitotic figures are noted (arrows), (Hematoxylin and Eosin, x200). C) Rhabdoid-like tumor cells (Hematoxylin and Eosin, x200). These retained INI-1 expression (not shown). D) Tumor cells at the periphery has conventional morphology of SEGA (right) and appear well demarcated from adjacent CNS tissue (left), (Hematoxylin and Eosin, x100)

Figure 4

Histopathological examination of the recurrent tumor. The recurrent tumor is composed predominantly of small mononuclear cells Necrosis is depicted in this image (star), (Hematoxylin and Eosin, x40)