TABLE 3:
Morphologic and Immunohistochemical Findings
| Malignant Peripheral Nerve Sheath Tumor | Cellular Schwannoma | p | |
|---|---|---|---|
| Morphologic findings | |||
| Fascicles | 38 (95%) | 16 (62%) | 0.002 |
| Schwannian Whorls | 2 (5%) | 14 (54%) | <0.001 |
| Thick-hyalinized vessels | 2 (5%) | 8 (31%) | 0.010 |
| Intravascular bulging | 20 (50%) | 4 (15%) | 0.004 |
| Perivascular hypercellularity | 19 (48%) | 2 (8%) | 0.001 |
| Capsule | 3 (8%) | 15 (62%) | <0.001 |
| Subcapsular lymphocytes | 4 (10%) | 11 (42%) | 0.003 |
| Macrophages | 0 | 7 (27%) | 0.001 |
| Necrosis | 31 (78%) | 4 (15%) | <0.001 |
| Mitoses/10HPF; Median (range) | 25 (1-90) | 2.5 (1-10) | <0.001 |
| ≥10 Mitoses/10HPF | 33 (83%) | 1 (4%) | <0.001 |
| Immunohistochemical stains | |||
| S100, Positive | 47 (41%) | 26 (100%) | <0.001 |
| Diffuse | 16 (14%) | 25 (96%) | <0.001 |
| SOX10; Positive | 21 (18%) | 26 (100%) | <0.001 |
| Diffuse | 0 | 17 (65%) | <0.001 |
| Neurofibromin; Positive | 12 (32%) | 25 (100%) | <0.001 |
| Diffuse | 7 (19%) | 24 (96%) | <0.001 |
| p16; Positive | 30 (27%) | 26 (100%) | <0.001 |
| Diffuse | 13 (12%) | 3 (12%) | 0.992 |
| EGFR; Positive | 35 (31%) | 0 | <0.001 |
| Diffuse | 7 (6%) | 0 | 0.348 |
| p75NTR; Positive | 32 (80%) | 8 (31%) | <0.001 |
| SOX2; Positive | 95 (83%) | 25 (96%) | 0.123 |
| p53; Positive | 30 (75%) | 20 (85%) | 0.766 |
| Ki67, %; Median (range) | 40.3 (1-84) | 7.6 (2-36) | <0.001 |
| ≥20% | 34 (87%) | 1 (4%) | <0.001 |
HPF: High-power fields; p values in bold are statistically significant.