Most commonly this tumour is due to carcinoma of:

Transperitoneal implantation of the carcinoma of stomach may occur in which the carcinoma cells pass from, stomach into the peritoneal cavity; they "gravitate" into the pelvis where the secondaries palpable on rectal examination I may develop. In females, occasionally, they "alight" upon the ovaries giving rise to Krukenberg tumors which are I liable to produce diagnostic confusion. The term Krukenberg tumor is classically reserved" for metastatic involvement of the ovary by a gastrointestinal tumor. The microscopic appearance of Krukenberg tumors shows characteristic mucin-containing signet-ring cells. This term is often used loosely to describe metastatic involvement of the ovaries in general. These metastatic lesions often present clinically as primary ovarian lesions and may have a similar radiographic appearance to primary carcinoma of the ovary.