Gastric xanthoma: a diagnostic problem on brushing cytology smears

Objective: To describe the cytologic findings of gastric xanthomas and to compare them with the findings of signet-ring adenocarcinoma because atypical xanthoma cells can be easily confused with signet-ring adenocarcinoma cells. Study Design: Five cases of gastric xanthoma that were confirmed by biopsy reports were selected for study. The patients' ages ranged between 50 and 58 years; 4 were men and 1 was a woman. Twenty-one cases of signet-ring adenocarcinoma confirmed by biopsy reports were selected for comparison. Special staining was performed. Results: The brushing cytology smears of the 5 cases of xanthoma revealed atypical cells, so initially they were reported as suspicious for signet-ring adenocarcinoma and biopsy examination advised. After learning of the histologic diagnosis of xanthoma, we performed special staining. The xanthoma cells were negative with periodic acid-Schiff (PAS) stain but showed a positive reaction with Oil red O and weakly positive reaction with Masson trichrome. Signet-ring adenocarcinoma cells showed a strongly positive reaction with PAS stain. Conclusion: Gastric brushing cytology findings of xanthomas have not been described before. At times the differentiation of atypical xanthoma cells from signet-ring adenocarcinoma cells is very difficult on brushing cytology smears. In this study the nuclear changes and special stains helped differentiate the 2 lesions