Abstract
Background : Signet ring cell lymphoma is a rare morphologic variant of non-Hodgkin’s lymphoma. Herein, we report a case of follicular lymphoma (FL) with signet ring cell features, which was diagnosed by EBUS-TBNA.
Case : A 68-year-old man was diagnosed as having FL by excisional biopsy of a submental lymph node a few months previously. Subsequently, PET/CT performed in an untreated status showed lymphadenopathy and FDG accumulation localized to the mediastinal lymph nodes. EBUS-TBNA was performed of subcarinal lymph node #7 to rule out the possibility of lung cancer at the Chiba Cancer Center. The cytology specimens showed small-to medium-sized lymphoid cells with irregular nuclei and cleaved cells with a binucleated appearance in a bloody background. Furthermore, scattered cells containing clear vacuoles were also seen. The histological specimens showed clusters of atypical cells with marked irregular nuclei and numerous cells containing cytoplasmic vacuoles, imparting a signet ring cell appearance. On immunohistochemistry, the atypical cells showed positivity for CD10, CD20, and BCL2 expressions.
Conclusions : The second biopsy revealed this case to be one of FL with signet ring cell features, while the signet ring cell features were not identified on the first biopsy. This case serves to underline the need to bear in mind the possibility of encountering such cases. Careful observations of the cytological features, including the findings of immunohistochemical analysis, are useful for the diagnosis.
