Histomorphological studies of Krukenberg tumor on early ovarian metastatic lesion

In ten cases of "early" Krukenberg tumor with only slight swelling of the ovary, histomorphological studies were performed to clarify the process of the formation of Krukenberg tumor. 1) The histological features of early metastatic lesion were classified into 3 types; lymph vessel permeation only, solid alveolar structure, and diffuse infiltration type. 2) Lymph vessel permeation in the ovarian hilum was observed in all cases. 3) In the diffuse infiltration type, signet-ring cells extended diffusely and radially via the lymph vessels, and, in the periphery, tumor cells leaked from the lymph vessels, infiltrating the stroma. At this stage, the response of ovarian stroma was slight, and signet-ring cells were present more abundantly in the vicinity of the infiltrated area. 4) In the solid alveolar type, the stroma was interposed in these lesions. 5) CEA staining revealed many CEA positive tumor cells in the proliferated stroma in which tumor cells failed to be detected. In summary, tumor cells infiltrate via the lymph vessels and leak into the stroma. Following the destruction of signet-ring cells, the mucus leaks into the stroma and it produces stromal edema and proliferation, eventually leading to a swollen ovary.