Table 3.
Pathologic features of the laryngeal neuroendocrine neoplasms (n = 27)
| Pathologic features | NET G2 (n = 9) | SCNEC (n = 16) | LCNEC (n = 2) |
|---|---|---|---|
| Initial erroneous biopsy diagnosis | Salivary gland tumor (n = 3) | SCC (n = 1), basaloid carcinoma (n = 1) | – |
| Median tumor size, cm (range) | 1.8 (0.6–3.6) | 3.8 (1.4–9.8) | 4.8 (4.5–11.1) |
| Macroscopy | Polypoid/globular | Ulcerated; ulceroproliferative | Ulcerated; ulceroproliferative |
| Microscopy | |||
| Architectural patterns | Trabeculae, nests, organoid | Diffuse solid sheets | Nests, trabeculae |
| Fibrovascular stroma | Prominent | Absent | Absent |
| Cellular monotony | Present | Present | Present |
| Cells | Plasmacytoid, infrequently clear, rhabdoid | Closely packed, <3 times the lymphocyte size; hyperchromatic, round to elongate nuclei, scant cytoplasm | Large, >3 times the lymphocyte size polygonal, basaloid to undifferentiated, vesicular nuclei, moderate cytoplasm |
| Prominent nucleoli | Absent | Absent | Present |
| Crushing artifacts | Absent | Present | Absent |
| Rosettes | 3 (33%) | 1 (6.3%) | 2 (100%) |
| Glomeruloid structures | 5 (55.5%) | 0 (0%) | 0 (0%) |
| Mitotic count/2 mm2 | 2–5 | 5-55a | 10–22 |
| Necrosis | 2 (22%) | 10 (63%) | 2 (100%) |
| Lymphovascular invasion | 1/8 (12.5%) | 3/4 (75%) | NA |
| Perineural invasion | 0/8 (0%) | 0/4 (0%) | NA |
| Involved resection margin | 2/8 (25%) | 0/4 (0%) | NA |
| Pathologic T stage | |||
| pT1-2 | 8/8 (100%) | 0/4 (0%) | NA |
| pT3-4b | 0/8 (0%) | 4/4 (100%) | NA |
| Lymph node metastasis | 5/8 (62.5%) | 10/12 (83.3%) | 2/2 (100%) |
| Immunohistochemistry | |||
| AE1/AE3 (n = 21) | 7/7 (100%) | 9/12 (75%) | 2/2 (100%) |
| Synaptophysin (n = 27) | 9/9 (100%) | 16/16 (100%) | 2/2 (100%) |
| Chromogranin (n = 27) | 9/9 (100%) | 13/16 (81.3%) | 2/2 (100%), focal |
| INSM1 (n = 12) | 6/6 (100%) | 4/4 (100%) | 2/2 (100%) |
| Rb loss (n = 23) | 0/6 (0%) | 13/15 (86.7%) | 2/2 (100%) |
| p53 aberrant (n = 22)b | 0/6 (0%) | 12/14 (80%) | 2/2 (100%) |
| Carcinoembryonic antigen (n = 14) | 3/7 (42.9%) | 2/5 (40%) | 0/2 (0%) |
| p40 (n = 7) | 0/1 (0%) | 1/4 (25%), focal | 0/2 (0%) |
| CK20 (n = 3) | ND | 0/3 (0%) | ND |
| GATA3 (n = 4) | 0/4 (0%) | ND | ND |
| Calcitonin (n = 15) | 3/9 (33.3%) | 0/6 (0%) | ND |
| CD99 (n = 8) | ND | 2/8 (25%) | ND |
| TTF1 (n = 11) | 3/6 (50%); focal | 3/3 (100%) | 1/2 (50%), focal |
| SMARCB1 loss (n = 5) | ND | 0/3 (0%) | 0/2 (0%) |
| ATRX loss (n = 5) | 0/3 (0%) | 0/2 (0%) | ND |
| S100/SOX10 (n = 5) | 0/2 (0%) | 0/1 (0%) | 0/2 (0%) |
| HMB45 (n = 1) | ND | ND | 0/1 (0%) |
| p16 (n = 7) | 0/1 (0%) | 4/4 (100%) | 0/2 (0%) |
| Ki-67 Labelling Index | 5–18% | 55–80% | 75 and 80% |
NET G2 neuroendocrine tumor, Grade 2, SCNEC small cell neuroendocrine carcinoma, LCNEC large cell neuroendocrine carcinoma, SCC squamous cell carcinoma, NA not applicable, ND Not done
aExtensive crushing artefacts in 4 cases precluded accurate mitotic counting
bAberrant p53 staining was seen as diffuse nuclear staining in the tumor cells (> 75% positive cells) in 12 cases and as a complete absence of p53 staining in the tumor cells with positive internal control (null-type staining) in 2 cases (1 case each of SCNEC and LCNEC)