Appendiceal Carcinoma with Krukenberg's Tumour Mimicking Primary Ovarian Cancer.

Appendiceal adenocarcinoma (AACa) is a rare tumour which represents 0.5% of all gastrointestinal malignancies. The prognosis is poor, because it is usually found at an advanced stage, that in turn, is partly due to a low threshold of suspicion and difficulties in diagnosis prior to surgery. It may occasionally demonstrate ovarian metastases that are large and which dominate the clinical and radiological presentations, leading to a misdiagnosis of an ovarian primary malignancy. We are reporting a case of an occult AACa which manifested clinically as a primary ovarian cancer which was at an advanced stage. Staging laparatomy revealed large bilateral ovarian tumours of clinical FIGO Stage III, with presumed appendiceal implants. Histological examination revealed a mucinous adenocarcinoma with a signet ring component, which involved bilateral ovaries and the appendix transmurally. Immunophenotypic analysis revealed a positive expression of CK 20 and CDX 2 and absence of CK 7 staining, which was compatible with appendiceal primary and ovarian metastases. The diagnosis was subsequently revised to AACa with Krukenberg's metastasis, Stage IV. Although AACas are uncommon, they should be considered in the differential diagnosis of intraabdominal masses and the distinction between ovarian and appendiceal primary malignancies is critical, as the treatment modalities vary.