Fig. 1Pathological findings of anaplastic lymphoma kinase (ALK)-positive pulmonary adenocarcinoma: histologic findings (A, E, I, M) and cytologic findings (B-D, F-H, J-L, N-P). (A) The tumor cells show solid-type adenocarcinoma. (B) A low power view of a Papanicolaou stain shows clusters of tumor cells in a mucinous background. (C) Tubulopapillary clusters are present in the background of a small amount of mucin. (D) The tumor cells are arranged in a hemorrhagic background. (E) Individual tumor cells are monotonous with bland nuclei. (F) The tumor cell aggregates show an acinar appearance. (G, H) Tubulopapillary and tubulocribriform patterns are seen. The tumor cells are monotonous. (I) The tumor cells have intranuclear inclusions. (J) The nuclei are vesicular and bland looking with a small nucleolus. (K) The tumor cells are pleomorphic, however the chromatin pattern is bland-looking. (L) The nucleus has a prominent nucleolus. (M) Signet ring cells are seen in histologic sections. (N, O) Cytologic finding of signet ring cells. The cells have eccentric nuclei with plump cytoplasms. (P) Immunohistochemical staining for ALK antibody showing cytoplasmic expression in the tumor cells.
Table 1.Comparison of the cytologic features of anaplastic lymphoma kinase (ALK)-positive and ALK-negative adenocarcinomas
Cytologic feature |
|
ALK-positive adenocarcinoma (%) |
ALK-negative adenocarcinoma (%) |
p-valuea
|
Background |
Mucin |
13/16 (81.3) |
6/16 (37.5) |
0.012 |
|
Hemorrhagic |
8/16 (50.0) |
5/16 (31.3) |
0.280 |
|
Necrotic |
3/16 (18.8) |
8/16 (50.0) |
0.063 |
Architecture |
Tubulopapillary |
15/16 (93.8) |
3/16 (18.8) |
< 0.001 |
|
Tubulocribriform |
15/16 (93.8) |
3/16 (18.8) |
< 0.001 |
|
Acini |
6/16 (37.5) |
13/16 (81.3) |
< 0.001 |
|
Sheet |
15/16 (93.8) |
14/16 (87.5) |
0.387b
|
|
Cluster |
9/16 (56.3) |
11/16 (68.8) |
0.465 |
|
Single |
11/16 (68.8) |
3/16 (18.8) |
0.004 |
|
Signet ring cell |
14/16 (87.5) |
1/16 (6.3) |
< 0.001 |
Nucleus |
Vesicular chromatin |
14/16 (87.5) |
2/16 (12.5) |
< 0.001 |
|
Small nucleoli |
10/16 (62.5) |
8/16 (50.0) |
0.476 |