Extrauterine (tubal) placental site nodule.

AIMS: The clinicopathological and immunohistochemical features of the second case of placental site nodule (PSN) of extrauterine, tubal location are presented.

METHODS AND

RESULTS

The lesion was incidentally found in the right tube during a cesarean section and eventual tubal ligation in a 23-year-old women gesta 2 para 1, after an uneventful 39-week intrauterine pregnancy. Grossly, the right Fallopian tube had a 1 cm dilatation filled by necrotic material. Microscopically, the lumen of the Fallopian tube was effaced and replaced by a rim of pleomorphic intermediate trophoblastic (IT) cells with pseudoinvasive parietal features which were positive for human placental lactogen, placental alkaline phosphatase, epithelial membrane antigen and CAM5.2. The Ki67 index was 3%.

CONCLUSION

Due to its bizarre microscopic appearance, this lesion should be included in the differential diagnosis with malignant conditions. Both origins from a previous subclinical extrauterine tubal pregnancy and a possible migration of IT from a uterine implantation are considered.