Diagnosis of an anemone cell tumor as a B-cell lymphoma by molecular analysis.

An 83-year-old man presented with mediastinal and axillary lymphadenopathy. Immunophenotyping and electron microscopy performed on an excision biopsy were inconclusive. On a repeat biopsy a year later the ultrastructural features typical of an anemone cell tumor were seen. A panel of monoclonal antibodies showed positivity for vimentin only. The diagnosis of a high-grade B-cell lymphoma could be made only after detection of immunoglobulin gene rearrangement by polymerase chain reaction gene amplification.