Pseudoxanthomatous salpingitis as an ex vivo model of fallopian tube serous carcinogenesis: a clinicopathologic study of 49 cases

Iron is a well-documented carcinogen based on both animal models and observational studies in humans. There are limited published data on pseudoxanthomatous salpingitis, an uncommon condition characterized by the accumulation of histiocytes containing iron and iron-related compounds-lipofuscin and hemosiderin-in the lamina propria of the fallopian tube. The clinical and pathologic features of 49 consecutive cases were evaluated. The mean patient age was 53. A history of endometriosis was found in 20%, infertility in 17%, and tubal ligation in 7%. Thirteen (27%) had endometrial cancer and 2 patients had prior radiation therapy for cervical carcinoma. Histologic evidence of endometriosis other than tubal pigment deposition was identified in 65%, and in the fallopian tubes in 35%. Pigment deposition was unilateral in 65% and multifocal or diffuse in 80%. Plasma cells, eosinophils, and neutrophils were present in the tubal lamina propria in 57%, 18%, and 24%, respectively. Hydrosalpinx was present in 51%. An iron stain was positive in pseudoxanthoma cells lacking hemosiderin in 14 of 18 cases (78%). By immunohistochemistry, 2 of 22 cases displayed p53 signatures. The Ki67 proliferation index was elevated (>10%) in 11 of 22 cases, with a mean index of 32% in those cases. An elevated proliferation index did not correlate with inflammation. In summary, these findings characterize the clinical and pathologic features of pseudoxanthomatous salpingitis and confirm its close association with endometriosis, occasional association with radiation therapy, and the presence of iron in the histiocytes. In view of the evolving paradigm shift implicating the fallopian tubal epithelium as the site of origin of high-grade extrauterine serous carcinoma, the presence of iron and iron-related compounds in the fallopian tube provides an opportunity to study the early events in high-grade serous carcinogenesis in a setting characterized by a well-documented carcinogen in close anatomic proximity to the putative epithelium of origin.