Figure 1
Sclerosing melanocytic nevus from the abdomen of a 22-year-old woman, with negative FISH assay. (A) There is a trizonal pattern, maturation and an atypical intraepidermal component above the sclerosis, which does not extend beyond the sclerosis. (B) HMB-45 stain shows maturation in the dermal component.
Figure 2
Sclerosing melanocytic nevus from the abdomen of a 53-year-old man, with negative the FISH assay. (A), (B) There is lamellar-type sclerosis involving the entire dermal component.
Figure 3
Sclerosing melanoma from the abdomen of a 67-year-old man. (A) There are remnants of a nevus below the melanoma (arrow) and a trizonal pattern. (B) Some melanocytes are in the epithelium of an eccrine duct (arrow). (C) Melanocytes within sclerosis are atypical, with prominent nucleoli. (D) There is a mitotic figure (arrow). (E) HMB-45 staining is irregular diffuse in the sclerotic dermal component (melanoma) but negative in the nevus below (arrow). There is prominent pagetoid spread in the epidermis. (F) The FISH assay was positive, showing loss of MYB (gold) relative to CEP6 (aqua) in 57% of tumor cell nuclei.
Figure 4
Sclerosing melanoma from the back of a 70-year-old female. (A) There are remnants of a nevus below sclerosis (arrow). (B) Melanocytes in the sclerosis do not show maturation and (C) are larger with irregular nuclei and prominent nucleoli compared to melanocytes in the adjacent nevus (left). (D) HMB-45 stain shows pagetoid spread in the epidermis, but is completely negative in the dermis. (E) Ki67 (brown)/melan A (red) shows no proliferative activity in the melanocytes in the deepest aspect of the sclerotic component; note less intense melan A positivity in the nevus below the melanoma (arrow). (F) The FISH assay was positive, showing gain in RREB1 (red) in 30% of tumor cell nuclei.
Table 1
Clinical and histopathologic parameters in relation to morphological diagnostic categories
| Parameter, n (%) | All | Nevus | Melanoma | Melanoma with nevus | P -value |
|---|---|---|---|---|---|
| N (%) | 90 | 26 (29) | 19 (21) | 45 (50) | |
| Age of the patients (years) (median; range) | 48; 21-89 | 38; 22-53 | 60; 21-89 | 51; 26-85 | < 0.001 |
| Maximum diameter* (mm) (median; range) | 9; 2-29 | 7; 2-14 | 8; 3-29 | 11; 4-25 | 0.014 |
| Location | 0.076 | ||||
| Back | 46 (51) | 9 (35) | 9 (47) | 28 (62) | |
| Other | 44 (49) | 17 (65) | 10 (53) | 17 (38) | |
| Extension along eccrine ducts** | 49/77 (64) | 5/21 (24) | 14/17 (82) | 30/39 (77) | < 0.001 |
| Evidence of regression | 29 (32) | 1 (4) | 12 (63) | 16 (36) | / |
| Lamellar sclerosis | 8 (9) | 6 (23) | 0 | 2 (4) | / |
| Marked inflammation in the sclerosis | 27 (30) | 2 (8) | 6 (32) | 19 (42) | / |
| Maturation in the sclerosis | 50 (56) | 25 (96) | 8 (42) | 17 (38) | / |
| Dermal mitoses present | 18 (20) | 1 (4) | 4 (21) | 13 (29) | / |
| Prominent nucleoli in the sclerosis | 52 (58) | 5 (19) | 16 (84) | 31 (69) | / |
| Intraepidermal component adjacent to the sclerosis | / | ||||
| Not atypical | 18 (20) | 17 (65) | 1 (5) | 0 | |
| Atypical | 17 (19) | 9 (35) | 1 (5) | 7 (16) | |
| Melanoma in situ | 55 (61) | 0 | 17 (89) | 38 (84) | |
| Severe cytological atypia in the epidermis above the sclerosis | 68 (76) | 9 (35) | 19 (100) | 40 (89) | / |
| Lentiginous growth above the sclerosis | 82 (91) | 19 (73) | 19 (100) | 44 (98) | / |
| Upward migration in the epidermis above the sclerosis | / | ||||
| No | 12 (13) | 9 (35) | 1 (5) | 2 (4) | |
| Lower half | 11 (12) | 7 (27) | 1 (5) | 3 (7) | |
| Focally in the upper half | 23 (26) | 9 (35) | 5 (26) | 9 (20) | |
| Prominent full thickness | 44 (48) | 1 (4) | 12 (63) | 31 (69) | |
| HMB-45 in the sclerotic component | 60 | 19 | 11 | 30 | / |
| Patchy, irregular | 37 (62) | 6 (32) | 10 (91) | 21 (70) | |
| Maturation or completely absent | 23 (38) | 13 (68) | 1 (9) | 9 (30) | |
| Ki67 in the sclerotic component | 66 | 19 | 13 | 34 | |
| No positivity in the lower half | 51 (77) | 19 (100) | 8 (62) | 24 (71) | / |
| Some positive melanocytes in the lower half, <5% overall | 13 (20) | 0 | 4 (31) | 9 (26) | |
| >5%, no gradient with the depth | 2 (3) | 0 | 1 (7) | 1 (3) | |
| Four-probe FISH in the sclerotic component | 41 | 16 | 7 | 18 | 0.001 |
| Positive | 14 (34) | 0 | 3 (43) | 11 (61) | |
| Negative | 27 (66) | 16 (100) | 4 (57) | 7 (39) |
Table 2
Clinical and histopathologic parameters in relation to FISH results in 41 lesions with FISH analysis of the sclerotic component
| Parameter, n (%) | All | FISH-positive | FISH-negative | P -value |
|---|---|---|---|---|
| N (%) | 41 | 14 | 27 | |
| Age of the patients (years) (median; range) | 48; 22-89 | 51; 42-89 | 48; 22-77 | 0.196 |
| Thickness of sclerosis (mm) (mean; range) | 0.85; 0.5-1.5 | 1.0; 0.7-1.5 | 0.8; 0.5-1.3 | 0.002 |
| Location | 0.096 | |||
| Back | 25 (61) | 11 (79) | 14 (52) | |
| Other | 16 (39) | 3 (21) | 13 (48) | |
| Extension along eccrine ducts | 21/38 (55) | 11/14 (71) | 10/24 (42) | 0.026 |
| Evidence of regression | 8 (20) | 4 (29) | 4 (15) | 0.411 |
| Maturation in the sclerosis | 29 (71) | 7 (50) | 22 (81) | 0.068 |
| Dermal mitoses present | 10 (24) | 5 (36) | 5 (19) | 0.267 |
| Prominent nucleoli in the sclerosis | 20 (49) | 11 (79) | 9 (33) | 0.009 |
| Melanoma in situ adjacent to the sclerosis | 23 (56) | 13 (93) | 10 (39) | 0.001 |
| Severe cytological atypia in the epidermis above the sclerosis | 27 (66) | 12 (86) | 15 (56) | 0.053 |
| Prominent full thickness upward migration in the epidermis above the sclerosis | 19 (22) | 10 (71) | 9 (33) | 0.026 |
| Patchy irregular HMB-45 in the sclerotic component | 22/38 (58) | 11/13 (85) | 11/25 (44) | 0.016 |
| No Ki67 positivity in the lower half of the sclerotic component | 28/39 (72) | 7/14 (50) | 21/25 (84) | 0.033 |