Cancer of other origin

Abstract

The peritoneal, pleural, and pericardial cavities may be the site of metastasis from practically any malignant tumor, including carcinomas, sarcomas, melanoma, hematological tumors, and pediatric cancers other than the aforementioned entities. The differential diagnosis is critically dependent on the age and gender of the patient, which are in turn likely to impact the choice of immunohistochemistry panels and molecular analyses performed. In adults, carcinomas predominate, and those not originating from the lung, ovary, or breast (discussed in other chapters) are discussed in this chapter, with the main focus on gastrointestinal primaries. Additionally discussed are carcinomas of other origin, including non-ovarian female genital tract cancers and carcinomas of the urothelial tract and the head and neck region. Non-epithelial cancers, including melanoma, sarcomas, and childhood cancers, are additionally discussed. The combination of morphology, immunohistochemistry, and, when mandated, molecular analysis allows for a conclusive diagnosis in the majority of cases.