Immunohistochemical detection of chimeric NPM-ALK protein (×400). A case of CD30⁺ primary CLCL (case no. 8; A) and a case of CD30⁺ secondary CLCL (case no. 1; B) both with a positive NPM-ALK amplification by both RT-PCR and DNA-PCR were stained with the monoclonal ALK1 antibody. A granular cytoplasmic and strong nucleolar staining was observed on the large lymphomatous cells in these 2 cases.