PMC3542424_01
Concomitant disseminated Langerhans cell histiocytosis and acute myeloid leukaemia. a Computed tomography showing bilaterally enlarged tonsils, more prominent on the left side (arrow). b Marrow aspirate showing predominance of myeloblasts. c Tonsillar biopsy, showing infiltration by a population of atypical cells with indistinct cytoplasmic borders. High-power view (insert) showed atypical cells with nuclei containing linear grooves. d The tonsillar atypical cells were positive for CD1a (immunoperoxidase). e The tonsillar atypical cells were positive for S100. f Trephine biopsy of the marrow, showing admixture of myeloblasts and atypical cells with elongated and grooved nuclei. g Atypical cells in the marrow were positive for S100
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Fig1
Computed tomography (CT) showed an infiltrative disease (Fig. 1a, arrow). Bone marrow examination confirmed acute myeloid leukaemia (AML) without maturation (Fig. 1b). Unexpectedly, a biopsy of the tonsillar mass showed infiltration by medium-sized atypical cells with indistinct cytoplasmic borders (Fig. 1c) and irregular and grooved nuclei (insert). These atypical cells were positive for CD1a (Fig. 1d) and S100 (Fig. 1e). Marrow trephine biopsy showed myeloblasts intermixed with numerous atypical cells (Fig. 1f), which were also S100 positive (Fig. 1g).