Intracranial tumor-forming papillary endothelial hyperplasia--a case report.

This is a report of extensive intracranial papillary endothelial hyperplasia in a 12-day-old twin. The infant presented with progressive macrocephaly, anemia and hydrocephalus. An MR image showed a large (6 x 5 cm) mass in the right middle cranial fossa. Histologic examination of the resected mass revealed multifocal hemorrhage, organizing in a floridly papillary pattern, in proximity to numerous fibrous bands containing reactive fibroblasts, scattered chronic inflammatory cells and foci of extramedullary hematopoiesis. Although the pattern was complex, neither the papillary regions nor the other areas in the lesion displayed solid proliferations of endothelial cells to support a diagnosis of angiosarcoma. Subsequent to the resection, the infant continued to have hemostatic abnormalities and increasing hydrocephalus. Repeat scans showed a recurrent mass (4 x 4 cm). The child was placed on a protocol for chemotherapy treatment. We hypothesize that the hemorrhage and subsequent organization could have been superimposed upon a preexistent vascular malformation or hemangioma even though Masson's trichrome stain does not unequivocally demonstrate this feature. Most importantly, we would like to emphasize the dilemmas involved in diagnosis and management of this benign disorder.