Fallopian tube metastases of non-gynaecological origin: a series of 20 cases emphasizing patterns of involvement including intra-epithelial spread

Aims: To determine the frequency and distribution of Fallopian tube involvement in patients with ovarian metastases of non-gynaecological origin. Methods and results: All Fallopian tube tissue was processed for histological examination in a consecutive series of 31 patients with ovarian metastases of non-gynaecological origin. The most common primary sites were appendix (n = 10) colon (n = 7), stomach (n = 6) and breast (n = 4). Twenty cases (65%) showed at least one type of tubal spread. Mural involvement was most common (14 cases) but serosal, intra-vascular, intra-epithelial and intra-lumenal spread were also identified in 12, 9, 8 and 11 cases respectively. Intra-epithelial involvement was restricted to the fimbrial epithelium and mimicked tubal carcinoma in situ (CIS) architecturally. Pagetoid invasion was noted in two of the cases. Conclusions: The Fallopian tubes are commonly involved in patients who have neoplasms metastatic to the ovaries. Metastases may show a CIS-like pattern of intra-epithelial spread and therefore small serous CIS-type lesions may not represent proof of tubal tumour origin in patients who have high-stage pelvic serous carcinomas. The frequency of intra-lumenal tumour cells supports transtubal spread as a likely mechanism for mucosal involvement by metastatic tumours involving the lower genital tract.