Fig. 2: A small cell ALK + ALCL case involving bone marrow and peripheral blood.

A At low magnification (×40), the bone marrow biopsy does not show obvious lymphoma. B At high magnification (×400), small lymphoma cells are present (red arrows) that have round to irregular nuclei, open chromatin, and small distinct nucleoli. C The lymphoma cells are positive for ALK (nuclear and cytoplasmic, ×400). D Peripheral blood smears show small to medium-sized lymphoma cells with irregular or indented nuclei and scant cytoplasm (×1000). A, B Hematoxylin-eosin stain. C Immunohistochemistry. D Wright–Giemsa stain.