Determining the significance of psammoma bodies in pelvic washings: A 10‐year retrospective review

Background Pelvic washing specimens are relatively common and are submitted for patients undergoing gynecologic surgery to evaluate them for metastatic or occult disease. Psammoma bodies are a relatively uncommon finding in these specimens. To date, large‐scale studies of their cytologic‐histologic correlates and thus clinical significance have been limited. Methods A 10‐year retrospective search for all pelvic washing specimens was performed, and all cases were reviewed for the presence of psammoma bodies. The findings for the corresponding surgical pathology specimens were then catalogued. Results Psammoma bodies were present in 138 cases (3.6% of 3840 total pelvic washings). More than half of the cases (n = 73 [53%]) were associated with benign processes, including mesothelial hyperplasia (n = 44), endosalpingiosis (n = 11), endometriosis (n = 11), and ovarian cystadenoma/cystadenofibroma (n = 7). Nineteen cases (14%) were associated with serous borderline tumors. Malignancies were noted in a third of the cases (n = 46 [33%]) and were most frequently low‐grade serous adenocarcinomas (n = 15), high‐grade serous adenocarcinomas (n = 11), or endometrioid endometrial carcinomas (n = 8). Patients found to have benign processes (median age, 50 years) or borderline disease (median age, 56 years) were significantly younger than patients with malignancies (median age, 65 years; P < .0001). In addition, the correlation of cytologic interpretation categories with concurrent histopathologic findings showed that cytologic analysis was highly sensitive and specific in determining the nature of underlying processes. Conclusions The majority of psammoma bodies noted in pelvic washings were associated with benign processes or borderline tumors, with approximately a third of the cases associated with malignancies. Psammoma bodies in pelvic washings from younger patients were significantly more likely to be associated with benign processes or borderline tumors.