PMC4745873_01
(a) Preoperative initial computed tomography (CT) 11 years after radiosurgery for an arteriovenous malformation in the left parietal lobe showing the cyst in the left thalamus. (b) Two years later, CT reveals that the size of the cyst is increased without hydrocephalus. (c) Four years later, CT reveals that the multilobular cyst is larger and accompanied by obstructive hydrocephalus. Preoperative magnetic resonance imaging (MRI) showing a cystic lesion in the left thalamus appearing isointense on T1-weighted imaging (d) and hyperintense on T2-weighted axial (e) and coronal (f) imaging as well as association with obstructive hydrocephalus. Note thickened cyst wall and septum in the middle of the cyst. Postoperative CT (g) and MRI (h) show shrinkage of the hematoma cavity and improvement of hydrocephalus. CT scan one year after surgery demonstrates neither recurrence of the hematoma nor progressive hydrocephalus (i).
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Eleven years after the radiosurgery for AVM, a cystic lesion with iso-low-density was noted in the left thalamus on computed tomography (CT) (Figure 1(a)). The lesion was followed every other year and eventually revealed that the isodense cystic mass had grown gradually and was accompanied by progressive obstructive hydrocephalus (Figures 1(b) and 1(c)). Magnetic resonance imaging (MRI) showed a cystic lesion with a septum that appeared iso- and hyperintense on T1- and T2-weighted imaging, respectively (Figures 1(d)-1(f)). Postoperative CT and MRI showed that the hematoma had been evacuated, and the hydrocephalus had improved (Figures 1(g) and 1(h)).
(a) Histological findings reveal hematoma capsule consisting of a dense collagenous layer with extensive invasion of macrophages, hematoxylin and eosin, x40. (b) Immunohistochemical findings showing numerous CD68-positive cells in the cyst wall, original magnification x40. (c) Vessel wall is thickened and internal elastica lamina is intact, revealing no residual nidus in the incised cyst wall, Masson, x100.
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