Bone marrow histopathologic findings at referral of 342 patients with SM
| Bone marrow characteristics . | No (%) of patients . | Median (range) . | ISM . | ASM . | SM-AHNMD . | P . |
|---|---|---|---|---|---|---|
| BM cellularity corrected for age, N = 327 | 70 (20-100) | 50 (20-100) | 75 (30-100) | 90 (30-100) | < .001 | |
| High | 200 (61) | 49 (32) | 24 (67) | 123 (91) | ||
| Normal | 108 (33) | 88 (58) | 9 (25) | 11 (8) | ||
| Low | 19 (6) | 15 (10) | 3 (8) | 1 (1) | ||
| BM % MC, N = 299 | 10 (1-90) | 10 (1-90) | 13 (1-70) | 11 (1-70) | .2 | |
| BM MC < 10 | 109 (36) | 58 (41) | 9 (26) | 42 (35) | .1 | |
| BM MC 10-30 | 151 (51) | 68 (48) | 17 (50) | 66 (55) | ||
| BM MC > 30 | 39 (13) | 15 (11) | 8 (24) | 12 (10) | ||
| BM MC nuclear morphology, N = 259 | .002 | |||||
| Oval | 191 (74) | 87 (78) | 21 (66) | 82 (73) | ||
| Elongated | 48 (19) | 24 (22) | 7 (22) | 17 (15) | ||
| Indented/lobulated | 16 (6) | 0 | 3 (9) | 10 (9) | ||
| Round | 4 (2) | 0 | 1 (3) | 3 (3) | ||
| BM MC granularity, N = 243 | ||||||
| Normal to > 50% | 164 (67) | 86 (82) | 16 (50) | 61 (60) | < .001 | |
| BM % blast, N = 342 | < .001 | |||||
| BM blast < 5 | 315 (92) | 159 (100) | 41 (100) | 111 (80) | ||
| BM blast 5-10 | 16 (5) | 0 | 0 | 16 (12) | ||
| BM blast > 10 | 11 (3) | 0 | 0 | 11 (8) | ||
| BM eosinophil infiltration grade, N = 257 | < .001 | |||||
| Absent | 27 (11) | 8 (7) | 5 (16) | 11 (10) | ||
| Minimal to moderate | 207 (81) | 99 (91) | 25 (78) | 82 (73) | ||
| Intense | 23 (9) | 2 (2) | 2 (6) | 19 (17) | ||
| BM fibrosis grade, N = 122 | ||||||
| 2+ or more | 44 (36) | 5 (14) | 8 (47) | 31 (46) | .004 | |
| BM MC immunophenotype (flow cytometry), N = 70 | ||||||
| CD2 positivity | 38 (54) | 27 (66) | 4 (50) | 7 (33) | .05 | |
| CD25 positivity | 65 (93) | 39 (95) | 8 (100) | 18 (86) | .4 | |
| BM MC immunophenotype (immunohistochemistry) | ||||||
| CD2 positivity, N = 18 | 3 (17) | 2 (15) | n/a | 1 (20) | n/a | |
| CD25 positivity, N = 23 | 23 (100) | 15 (100) | n/a | 8 (100) | n/a |
| Bone marrow characteristics . | No (%) of patients . | Median (range) . | ISM . | ASM . | SM-AHNMD . | P . |
|---|---|---|---|---|---|---|
| BM cellularity corrected for age, N = 327 | 70 (20-100) | 50 (20-100) | 75 (30-100) | 90 (30-100) | < .001 | |
| High | 200 (61) | 49 (32) | 24 (67) | 123 (91) | ||
| Normal | 108 (33) | 88 (58) | 9 (25) | 11 (8) | ||
| Low | 19 (6) | 15 (10) | 3 (8) | 1 (1) | ||
| BM % MC, N = 299 | 10 (1-90) | 10 (1-90) | 13 (1-70) | 11 (1-70) | .2 | |
| BM MC < 10 | 109 (36) | 58 (41) | 9 (26) | 42 (35) | .1 | |
| BM MC 10-30 | 151 (51) | 68 (48) | 17 (50) | 66 (55) | ||
| BM MC > 30 | 39 (13) | 15 (11) | 8 (24) | 12 (10) | ||
| BM MC nuclear morphology, N = 259 | .002 | |||||
| Oval | 191 (74) | 87 (78) | 21 (66) | 82 (73) | ||
| Elongated | 48 (19) | 24 (22) | 7 (22) | 17 (15) | ||
| Indented/lobulated | 16 (6) | 0 | 3 (9) | 10 (9) | ||
| Round | 4 (2) | 0 | 1 (3) | 3 (3) | ||
| BM MC granularity, N = 243 | ||||||
| Normal to > 50% | 164 (67) | 86 (82) | 16 (50) | 61 (60) | < .001 | |
| BM % blast, N = 342 | < .001 | |||||
| BM blast < 5 | 315 (92) | 159 (100) | 41 (100) | 111 (80) | ||
| BM blast 5-10 | 16 (5) | 0 | 0 | 16 (12) | ||
| BM blast > 10 | 11 (3) | 0 | 0 | 11 (8) | ||
| BM eosinophil infiltration grade, N = 257 | < .001 | |||||
| Absent | 27 (11) | 8 (7) | 5 (16) | 11 (10) | ||
| Minimal to moderate | 207 (81) | 99 (91) | 25 (78) | 82 (73) | ||
| Intense | 23 (9) | 2 (2) | 2 (6) | 19 (17) | ||
| BM fibrosis grade, N = 122 | ||||||
| 2+ or more | 44 (36) | 5 (14) | 8 (47) | 31 (46) | .004 | |
| BM MC immunophenotype (flow cytometry), N = 70 | ||||||
| CD2 positivity | 38 (54) | 27 (66) | 4 (50) | 7 (33) | .05 | |
| CD25 positivity | 65 (93) | 39 (95) | 8 (100) | 18 (86) | .4 | |
| BM MC immunophenotype (immunohistochemistry) | ||||||
| CD2 positivity, N = 18 | 3 (17) | 2 (15) | n/a | 1 (20) | n/a | |
| CD25 positivity, N = 23 | 23 (100) | 15 (100) | n/a | 8 (100) | n/a |
ISM indicates indolent systemic mastocytosis (SM); ASM, aggressive SM; SM-AHNMD, SM with associated clonal hematologic non–mast cell lineage disease; %, percentage; BM, bone marrow; MC, mast cell; No., number; and n/a, not accessed or not applicable.