The resected lymph nodes after the salvage neck dissection were assessed first determining the representative slide for each patient as previously described and then evaluated for the various histopathological criteria (Table
1).
Table 1
Description of histopathological parameters assessed on the representative slide for each patient
Viable tumor cells | | | |
No (%) | 45 (60) | | |
Yes (%) | 30 (40) | | |
Area mm2 | | 16.8 | 32.3 |
Extranodal extension | | | |
No (%) | 62 (82,7) | | |
Yes (%) | 13 (17.3) | | |
Necrosis | | | |
No (%) | 24 (32) | | |
Yes (%) | 52 (68) | | |
Area mm2 | | 16.1 | 33 |
Max. Diameter mm | | 2.8 | 4.4 |
Swirled keratin debris | | | |
No (%) | 57 (76) | | |
< 50% (%) | 11 (14.7) | | |
≥ 50% (%) | 7 (9.3) | | |
Area mm2 | | 16.6 | 49.2 |
Max. diameter mm | | 2.2 | 5.1 |
Foamy Histiocytes | | | |
No (%) | 54 (72) | | |
Yes (%) | 21 (28) | | |
Bleeding residues | | | |
No (%) | 60 (80) | | |
Yes (%) | 15 (20) | | |
Fibrosis | | | |
No (%) | 16 (21.3) | | |
Yes (%) | 59 (78.7) | | |
Area mm2 | | 92.8 | 98.4 |
Max. diameter mm | | 12.1 | 12.1 |
Elastosis | | | |
No (%) | 54 (72) | | |
Yes (%) | 21 (28) | | |
Pyknotic cells | | | |
No (%) | 33 (44) | | |
Yes (%) | 42 (56) | | |
Calcification | | | |
No (%) | 48 (64) | | |
Yes (%) | 27 (36) | | |
Cholesterol crystals | | | |
No (%) | 54 (72) | | |
Yes (%) | 21 (28) | | |
Multinucleated giant cells | | | |
No (%) | 21 (68) | | |
Yes (%) | 24 (32) | | |
Perineural invasion | | | |
No (%) | 74 (99) | | |
Yes (%) | 1 (1) | | |
Vascular invasion | | | |
No (%) | 72 (96) | | |
Yes (%) | 3 (4) | | |
Tissue blocks/slides from
n = 75 patients were available, meaning 3 out of the 78 Patients (3.8%) from the study cohort from Rüegg et al. [
8] were excluded from our study. Of the patients evaluated, we found viable tumor cells in
n = 30 cases (40%) with a mean area measured of 16.8 mm
2 (± 32.3) in comparison to
n = 45 patients (60%) with no viable tumor cells present. There was an extranodal extension in
n = 13 patients (17.3%), so 43.3% of cases with viable tumor cells also showed an extranodal extension. Of the histopathological features indicating some kind of treatment effect, necrosis was shown in
n = 52 patients (68%) with a mean area of 16.1 mm
2 (± 33) and mean maximal diameter of 2.8 mm (± 4.4). Swirled keratin debris was present in
n = 18 cases (24%), of which
n = 11 (14.7%) were < 50% and
n = 7 (9.3%) were ≥ 50% nucleated. Quantitatively, the swirled keratin debris showed a mean area of 16.6 mm
2 (± 49.2) and mean maximal diameter of 2.2 mm (± 5.1). Further, foamy histiocytes were present in
n = 21 (28%) and bleeding residues in
n = 15 (20%) cases. Fibrosis was shown in
n = 59 patients (78.7%) with a mean area of 92,8 mm
2 (± 98.4) and a mean maximal diameter of 12.1 mm (± 12.1). Elastosis was present in
n = 21 (28%), pyknotic cells in
n = 42 (56%), calcifications in
n = 27 (36%), cholesterol crystals in
n = 21 (28%), and multinucleated giant cells in
n = 24 (32%) cases. Perineural invasion was only detected in
n = 1 (1,3%) and vascular invasion in
n = 3 patients (4%). Due to the low numbers, we did not include these two parameters in our further statistical analysis.