Fig. 1(A-C) Gross and histologic findings of biphasic mesothelioma. (A) The tumor shows diffuse thickening of the pleura and encases the lung with up to 2.5 cm in thickness. (B) The tumor consists of nests of epithelioid cells. (C) In some parts, tumor cells show spindle morphology corresponding to sarcomatoid component. (D-F) Gross and histologic findings of epithelioid mesothelioma. (D) The parietal pleura is diffusely thickened and nodular. It invades lung parenchyma. (E) The tumor is composed of glandular structures. (F) The tumor cells show poorly differentiated features and marked pleomorphism.
Fig. 2Unusual histologic features of epithelioid mesotheliomas. (A) The large tumor cells exhibit well-defined borders and dense eosinophilic cytoplasm, consistent with deciduoid features. (B) This case shows a microcystic structure with marked cellular pleomorphism. (C, D) Another case also reveals a microcystic structure and signet ring cell appearances.
Fig. 3Histologic features of small biopsy samples of mesothelioma. Tumor cells invade fibrous stroma (A) and fat (B). (C) In one case where the stromal component is not included in the specimen, tumor cells are arranged in complex papillae and show moderate cellular atypia. (D) The presence of necrosis favors the diagnosis of malignant mesothelioma.
Fig. 4The histologic and immunohistochemical features of malignant mesothelioma in the needle biopsy samples. (A) The tumor cells exhibit epithelioid morphology with nuclear atypia. (B) The stain of calretinin shows diffuse nuclear and cytoplasmic staining in tumor cells of malignant mesothelioma. (C) HMBE-1 shows a thick membranous staining pattern. (D) The stain of Wilms tumor 1 shows diffuse nuclear staining.
Table 1Histologic features of needle biopsy samples
|
No. of cases (%) |
Stroma |
|
Present |
26/33 (78.8) |
Absent |
7/33 (21.2) |
Stromal invasion |
|
Present |
26/33 (78.8) |
Absent |
7/33 (21.2) |
Cellularity |
|
High |
27/33 (81.8) |
Moderate |
6/33 (18.2) |
Structure |
|
Diffuse |
23/33 (69.7) |
Complex papillae |
9/33 (27.3) |
Simple papillae |
1/33 p.0) |
Necrosis |
|
Present |
11/33 (33.3) |
Absent |
22/33 (66.7) |
Inflammation |
|
Mild |
28/33 (84.8) |
Marked |
5/33 (15.2) |
Atypia |
|
Mild |
8/33 (24.2) |
Moderate |
22/33 (66.7) |
Severe |
3/33 (9.1) |
Mitosis |
|
Present |
12/33 (36.4) |
Absent |
21/33 (63.6) |
Table 2Results of immunohistochemistry
|
Positive (%) |
Focal positive (%) |
Negative (%) |
Unsatisfactory (%) |
Positive markers |
|
|
|
|
Calretinin |
20/36 (55.6) |
6/36 (16.7) |
9/36 (25.0) |
1/36 (2.8) |
WT-1 |
10/21 (47.6) |
7/21 (33.3) |
4/21 (19.0) |
0/21 (0) |
HBME-1 |
23/33 (69.7) |
5/33 (15.2) |
4/33 (12.1) |
1/33 (3.0) |
Vimentin |
9/9 (100) |
0/9 (0) |
0/9 (0) |
0/9 (0) |
CK (AE1/AE3) |
9/10 (90) |
1/10 (10) |
0/10 (0) |
0/10 (0) |
Negative markers |
|
|
|
|
TTF-1 |
0/32 (0) |
0/32 (0) |
31/32 (96.9) |
1/32 (3.1) |
CEA |
0/16 (0) |
0/16 (0) |
16/16 (100) |
0/16 (0) |
Table 3Epidemiologic data of 66 malignant mesothelioma cases
|
n |
Age (yr) |
28-80 (average, 56.84) |
Sex |
|
Male |
42/66 |
Female |
24/66 |
Asbestos exposure |
|
Exposure |
1/66 |
No exposure |
3/66 |
Not available |
62/66 |
Occupational information |
|
Housewife |
8/66 |
Office worker |
5/66 |
Businessman |
4/66 |
Teacher |
2/66 |
Etc. |
9/66 |
Not available |
38/66 |
Residential information |
|
Gyeongsang-do |
18/66 |
Seoul |
14/66 |
Gyeonggi-do |
12/66 |
Jeolla-do |
8/66 |
Chungcheong-do |
5/66 |
Gangwon-do |
2/66 |
Incheon |
1/66 |
Jeju-do |
1/66 |
Russia |
1/66 |
Not available |
4/66 |