Significance of "signet-ring cells" seen in exfoliative and aspiration cytopathology.

"Signet ring cell" (SRC) is a phenotypic designation for a cell with a large clear cytoplasmic vacuole displacing the nucleus to the periphery. Our study focuses on the cytopathologic significance of SRCs in the context of diagnostic range, ancillary studies, and clinical prognosis. A retrospective review revealed 83 cases of SRCs diagnosed in a 16-year period (1989-2004). Clinical data and ancillary studies were reviewed. The most common specimen types consisted of abdominal and pleural SCFs (45, 54%). Of the 83 cases, 13 (16%) were benign, 65 (78%) malignant, and 5 (6%) indeterminate. Benign lesions mostly comprised of reactive mesothelial cells (9 cases, 69%). Of the malignant lesions, 47 (72%) were metastases, 14 (22%) were primary cancers and 4 (6%) were local cancer recurrences. Adenocarcinoma was the most prevalent malignant diagnosis (53, 82%). All FNAs with SRCs had a malignant diagnosis. Cytopathologic diagnoses impacted clinical prognosis and survival times. The most common site for occurrence of SRCs is abdominal fluid and their presence usually indicates malignancy (78%). Most cancers with SRCs are metastatic in origin (72%) with a significant proportion from unknown primaries (51%). Cytologic diagnoses of SRCs for cancer have 97% sensitivity and 100% specificity. (c) 2009 Wiley-Liss, Inc.