TABLE 1.
Pathologic Features of PAs and LGSI at Diagnosis
| Features n (%) | PA, n = 50 | LGSI, n = 17 |
|---|---|---|
| Biphasic pattern | 21 (42) | 2 (12) |
| Microcysts | 20 (40) | 4 (24) |
| Nuclear atypia | ||
| Mild | 29 (58) | 13 (76) |
| Moderate | 19 (38) | 4 (24) |
| Severe | 2 (4) | 0 (0) |
| Multinucleated cells | 27 (54) | 4 (24) |
| Oligodendroglial-like cells | 2 (4) | 1 (6) |
| Cellularity | ||
| Low | 19 (38) | 9 (53) |
| Moderate | 31 (62) | 8 (47) |
| High | 0 (0) | 0 (0) |
| Rosenthal fibers | 39 (78) | 2 (12) |
| Granular bodies | 29 (58) | 2 (12) |
| Chronic inflammation | 20 (40) | 5 (29) |
| Hemosiderin-laden macrophages | 23 (46) | 3 (18) |
| Calcification | 3 (6) | 0 (0) |
| Necrosis | 2 (4) | 0 (0) |
| Leptomeningeal extension | 12 (24) | 2 (12) |
| Fascicular pattern of growth | 6 (12) | 1 (6) |
| Vascular changes | ||
| Hyalinization | 34 (68) | 7 (41) |
| Glomeruloid Vessels | 29 (58) | 5 (29) |
| Infiltration | ||
| Absent | 8 (16) | 2 (12) |
| Partial | 29 (58) | 5 (29) |
| Prominent | 7 (14) | 6 (35) |
| Unable to assess | 6 (12) | 4 (24) |
LGSI, Low-grade astrocytomas, subtype indeterminate; PA, pilocytic astrocytoma.