Patient PRS-NF2, clinical presentation. A-B) PRS-NF2 at age 17 years with severe micrognathia, ocular hypertelorism and microcephaly. Measurements: outer canthal distance 8.3 cm, 25th %ile; inner canthal distance 4 cm, 3 S.D. above the mean; interpupillary distance 5.5 cm, 25th %ile; head circumference 52 cm, 2nd %ile, weight 41.8 kg, 2-1.4 S.D. below the mean; height 156 cm, 10th-25th %ile. C-D) MRI of brain shows bilateral cerebellopontine angle tumors (left: 3.1 × 4.6 × 6.1 cm, right: 1 × 1.2 × 1.1 cm; arrows) with mass effect by the left tumor on the brain stem, pons and cerebellum, with associated effacement of the 4th ventricle, enlargement of the 3rd and lateral ventricles, enlarged cervical cord and tonsillar herniation. E-F) MRI of spine shows holocord syrinx with large neurofibroma at C7-T1 (E), causing cord compression and canal stenosis. Some of the other extramedullary intradural neurofibromas described in the text are also shown. G-H) Histological analysis of the resected left cerebellopontine angle tumor shows spindled nuclei with dense to finely granular chromatin and cells with long tapering cytoplasmic processes with inconspicuous outer membranes. Panel G demonstrates both short fascicular bundles with dense Antoni type A area (right upper corner) and loose hypocellular Antoni type B area (middle to left lower corner) characteristic of schwannomas (H&E, G-100×). Panel H is 400 × magnification of the inset from panel G).