Adenomatoid Tumor of Fallopian Tube With "Deciduoid" Morphology and Atypical Nuclear Features

Adenomatoid tumor is a benign neoplasm of mesothelial origin. Adenomatoid tumor in female genital tract shows typical morphologic features with bland nuclei. Deciduoid morphology has not been reported in adenomatoid tumor. Tumors with deciduoid cells and atypical nuclear features may pose a diagnostic challenge and raise the suspicion of malignancy. We present a case of fallopian tube adenomatoid tumor with deciduoid morphology and atypical nuclear features in a 39-year-old woman with prolonged progestin therapy. We hypothesize that the unusual morphological changes in adenomatoid tumor, like deciduoid morphology and nuclear atypia, may be secondary to hormone effects.