Concomitant lymphoma and metastatic carcinoma in a lymph node: diagnosis by fine-needle aspiration biopsy in two cases.

Concomitant lymphoma and metastatic carcinoma are an unusual occurrence in a lymph node. We report two patients in whom synchronous malignancies were diagnosed by fine-needle aspiration biopsy (FNAB). In one case, the FNAB diagnoses of both small lymphocytic lymphoma and metastatic breast carcinoma were the initial diagnoses. In the second case, metastatic poorly differentiated squamous carcinoma was an unexpected finding in a patient with a history of small lymphocytic lymphoma. The aspirates in both cases showed two distinct cell populations, one consisting of a dispersed population of small uniform lymphoid cells and the other comprising large atypical single cells and cohesive clusters of epithelial cells. In both cases, the cytologic diagnoses were supported by immunohistochemical and flow cytometric studies.