Immunohistopathological features of anaplastic large‐cell lymphoma according to anaplastic lymphoma kinase expression and bone marrow involvement pattern

Abstract

The immunohistopathological features of lesions involving the bone marrow (BM) were examined in patients with anaplastic large-cell lymphoma (ALCL) to identify the most useful markers for the detection of BM involvement in ALCL. A total of 80 patients with ALCL were enrolled, of whom 15 (18.8%) showed BM involvement. Anaplastic lymphoma kinase-negative (ALK-) patients (n=11) showed a nodular BM involvement pattern more frequently than ALK+ patients (n=4; 72.7% versus 25.0%, P=0.095). Patients with interstitial BM involvement were more frequently ALK+ than those with nodular BM involvement (50.0% versus 11.1%, P=0.095). CD30 positivity was the strongest indicator of the presence of BM lesions, regardless of the BM involvement pattern. The application of CD30 in cases without morphological evidence of BM involvement detected subtle BM involvement by ALCL in 13.7% of cases, which were predominantly ALK+. The immunohistopathological features of BM lesions in patients with ALCL differ according to ALK status and BM involvement pattern. CD30 is the most useful marker for the identification of BM lesions in ALCL patients and should be employed in all ALCL patients without exception, especially ALK+ cases.