Primary primitive neuroectodermal tumor of the uterus: a report of two cases and review of the literature.

Background: Primary primitive neuroectodermal (pPNET) tumors rarely occur in adults, and they very rarely present as primary tumors of the uterus. Only 12 reported cases of pPNET of the uterus have been published in the English literature. We report two additional cases treated at the Roswell Park Cancer Institute, Buffalo, NY, between 1999 and 2002.

Cases: Two postmenopausal patients presenting with abnormal uterine bleeding underwent endometrial biopsy, and subsequently staging laparotomy. The diagnosis of pPNET in both cases was confirmed only by extensive immunohistochemical analysis of the tumors. One patient with disease confined to an endometrial polyp received no adjuvant therapy, while the second patient with extrauterine disease received adjuvant pelvic radiation followed by chemotherapy.

Conclusions: The diagnosis of pPNET of the uterus may be a challenge. Features of diagnostic significance include positive staining with neuron-specific enolase, presence of neurosecretory granules, and positive staining with the MIC-2 gene. Currently, there is no uniformity in the treatment of these cases since the majority of the patients reported to date have had surgery, chemotherapy, and/or radiation therapy.