Heterogeneous genetic alterations in ovarian mucinous tumors: application and usefulness of laser capture microdissection.

Histologic observation of ovarian mucinous tumors suggests that there is a multistep transition through the accumulation of genetic alterations. We analyzed loss of heterozygosity (LOH) and replication error (RER) on TP53 and D17S855 as well as K-ras point mutations of the heterogeneous histologic areas of the same tumor in 26 cases of ovarian mucinous tumor. The laser capture microdissection (LCM) technique has been applied to the study of K-ras point mutation in 10 cases. As for genetic alterations for LOH or RER on TP53 and D17S855, 2 (1 borderline tumor and 1 carcinoma) of 14 cases and 4 (1 borderline tumor and 3 carcinomas) of 12 cases, respectively, showed genetic heterogeneities in different histologic areas. Six (2 borderline tumors and 4 carcinomas) of 18 cases showed heterogeneity of K-ras point mutation in the different histologic areas of the same tumor, and 5 (1 cystadenoma with Brenner tumor component, 2 borderline tumors, and 2 carcinomas) of 10 cases showed heterogeneous K-ras mutation pattern in the same tumor when the LCM technique was used. Atypical areas tended to show K-ras point mutations frequently. Out of 3 cases of mixed mucinous cystadenoma and Brenner tumor, 1 case showed K-ras point mutation in the Brenner tumor area but not in the area of mucinous cystadenoma. These preliminary results suggest that a subset of ovarian mucinous tumors occur through multistep carcinogenesis and show that LCM is useful for molecular pathologic studies.

Extra-abdominal desmoid tumor presenting as an intrathoracic tumor: case report and literature review.

A case of an extra-abdominal desmoid tumor presenting as an intrathoracic tumor (intrathoracic desmoid tumor) in a 46-year-old woman is reported. The tumor originated in the left chest wall and protruded into the left pleural cavity. Simple resection was carried out. The tumor, measuring 13 x 9 x 7 cm, was solid, gray-tan in color, and covered with parietal pleura. Histologically, the tumor was composed of a hypocellular arrangement of spindle-shaped cells with a fibromyxoid background. In some areas, keloid-like hyalinized collagen fibers proliferated, and a perivascular hypercellular area was seen. Immunohistochemical analysis showed that the cytoplasms of the tumor cells were strongly positive for vimentin, and some tumor cells were positive for alpha-smooth muscle actin, but all tumor cells were negative for CD34. These findings were consistent with the characteristics of an intrathoracic desmoid tumor. The differential diagnoses, in particular solitary fibrous tumor and tumors with a myofibroblastic nature, are discussed.