Atypical placental site nodules: A retrospective case series

Atypical placental site nodule (APSN) is a rare diagnosis, representing remnants of a previous pregnancy and extravillous trophoblast tissue. These lesions are potential precursor lesions to rare forms of Gestational trophoblastic neoplasia (GTN). Recent data suggest up to a 15% risk of malignancy occurring either concurrently or manifesting within a few months of diagnosis. These patients are often young with future fertility considerations. Prognosis, treatment, and clinical follow-up of APSN cases currently remain a matter of debate. This study aimed to address and explore some of these issues.

Retrospective case series analysis was performed between 1st January 2000 and 31st December 2023 at the Sheffield Trophoblastic Disease Centre, Sheffield, UK. Patients on conservative management were asked at routine follow-up telephone consultations if they would consider a completion hysterectomy in light of the risk of progression to GTN.

Twenty-two cases of APSN were registered, of which 10 (45%) received surgical management. Two (20%) cases were incidentally diagnosed following total abdominal hysterectomy (TAH) for other indications and eight (80%) had a TAH within twelve months of their initial diagnosis as part of primary management. None had histological evidence of GTN. Of the twelve (55%) patients initially opting primarily for conservative management, three (25%) decided to have a TAH performed based on the current evidence for risk of malignant transformation, eight (67%) indicated they would have a TAH based on advice from the center, and one (8%) was uncertain. No patients were diagnosed with GTN.

In this study, we found no evidence of malignant transformation in our patients, which conflicts with other published data conferring an 11%-14% risk of malignant transformation. An international consensus opinion needs to be reached within the Gestational trophoblastic community regarding the optimal advice, management, and follow-up regimens for patients diagnosed with APSN.