Suggested diagnosis and if additional diagnostic IHC staining would be ordered by 20 pathologists for 52 unselected bronchial and lung biopsies based on H&E, p40 and TTF-1 (clone SPT24) staining (the reference diagnosis, and if additional IHC staining was performed and used for diagnostics, is marked in grey)
| Case | Suggested diagnosis | Additional IHC* | |||||||||||||
| AC | SqCC | SCLC | NSCC probably LCNEC | CT | NSCC other | NSCC NOS | Non-epithelial malignancy | Metastasis | Suspect malignancy | Unclear atypia | Benign/Non-neoplastic | No reply | Yes | No | |
| 1 | 17 | 3 | 7 | 12 | |||||||||||
| 2 | 20 | 16 | 3 | ||||||||||||
| 3† | 5 | 1 | 1 | 7 | 6 | 8 | 11 | ||||||||
| 4‡ | 3 | 2 | 8 | 1 | 1 | 4 | 1 | 18 | 1 | ||||||
| 5 | 18 | 1 | 1 | 9§ | 10 | ||||||||||
| 6 | 1 | 19 | 18 | 1 | |||||||||||
| 7 | 6 | 2 | 1 | 9 | 2 | 18 | 1 | ||||||||
| 8 | 10 | 5 | 5 | 16 | 3 | ||||||||||
| 9 | 7 | 3 | 10 | 7 | 12 | ||||||||||
| 10 | 18 | 1 | 1 | 12§ | 7 | ||||||||||
| 11 | 20 | 16 | 3 | ||||||||||||
| 12 | 20 | 19 | 0 | ||||||||||||
| 13 | 5 | 2 | 5 | 8 | 18 | 1 | |||||||||
| 14 | 1 | 2 | 16 | 1 | 17 | 2 | |||||||||
| 15 | 18 | 1 | 1 | 7§ | 12 | ||||||||||
| 16 | 1 | 1 | 1 | 17 | 7 | 12 | |||||||||
| 17 | 19 | 1 | 4§ | 15 | |||||||||||
| 18 | 1 | 18 | 1 | 15 | 4 | ||||||||||
| 19 | 20 | 3 | 16 | ||||||||||||
| 20 | 3 | 8 | 9 | 6 | 13 | ||||||||||
| 21 | 16 | 3 | 1 | 10 | 9 | ||||||||||
| 22 | 20 | 19 | 0 | ||||||||||||
| 23¶ | 18 | 1 | 1 | 8 | 11 | ||||||||||
| 24† | 1 | 2 | 2 | 2 | 13 | 11 | 8 | ||||||||
| 25 | 20 | 1 | 18 | ||||||||||||
| 26 | 5 | 1 | 2 | 9 | 3 | 17 | 2 | ||||||||
| 27 | 1 | 19 | 2 | 17 | |||||||||||
| 28 | 1 | 1 | 18 | 4 | 15 | ||||||||||
| 29 | 2 | 1 | 17 | 19 | 0 | ||||||||||
| 30 | 18 | 2 | 3 | 16 | |||||||||||
| 31 | 19 | 1 | 18 | 1 | |||||||||||
| 32 | 19 | 1 | 0 | 19 | |||||||||||
| 33 | 2 | 17 | 1 | 19 | 0 | ||||||||||
| 34** | 8 | 1 | 4 | 6 | 1 | 13§ | 6 | ||||||||
| 35 | 16 | 2 | 2 | 8 | 11 | ||||||||||
| 36 | 1 | 1 | 18 | 2 | 17 | ||||||||||
| 37 | 18 | 1 | 1 | 3 | 16 | ||||||||||
| 38 | 7 | 2 | 1 | 5 | 4 | 1 | 14 | 5 | |||||||
| 39 | 4 | 2 | 14 | 10 | 9 | ||||||||||
| 40† | 17 | 2 | 1 | 6 | 13 | ||||||||||
| 41¶ | 8 | 2 | 7 | 3 | 18 | 1 | |||||||||
| 42 | 18 | 1 | 1 | 17 | 2 | ||||||||||
| 43 | 12 | 1 | 2 | 2 | 3 | 8§ | 11 | ||||||||
| 44 | 4 | 1 | 3 | 7 | 5 | 11 | 8 | ||||||||
| 45 | 2 | 11 | 1 | 3 | 3 | 10 | 9 | ||||||||
| 46 | 18 | 1 | 1 | 6 | 13 | ||||||||||
| 47 | 17 | 2 | 1 | 6 | 13 | ||||||||||
| 48¶ | 7 | 12 | 1 | 13 | 6 | ||||||||||
| 49 | 2 | 3 | 15 | 18 | 1 | ||||||||||
| 50 | 1 | 1 | 18 | 3 | 16 | ||||||||||
| 51 | 3 | 2 | 14 | 1 | 6 | 13 | |||||||||
| 52†† | 6 | 14 | 19 | 0 | |||||||||||
*One pathologist did not state if additional IHC would be ordered.
†Follow-up sample showed AC/NSCC.
‡Considered mixed SCLC/LCNEC by the reference standard.
§Given the morphology and results of p40 and TTF-1, the additional IHC stainings were not necessary for the reference diagnosis.
¶LCNEC/carcinoid diagnosis was confirmed on resection.
**Focal sarcomatoid features.
††Despite comprehensive analyses not perfectly clear if lung cancer or recurrent breast cancer.
AC, adenocarcinoma; CT, carcinoid tumour; IHC, immunohistochemistry; LCNEC, large cell neuroendocrine carcinoma; NSCC NOS, non-small cell carcinoma not otherwise specified; NSCC, non-small cell carcinoma; SCLC, small cell lung carcinoma; SqCC, squamous cell carcinoma; TTF-1, thyroid transcription factor-1.