Question

A 23-year-old man with a 5-year history of acute lymphoblastic leukemia (ALL) and who was in remission after chemotherapy treatment presenting with a shoulder mass (Figs. 1–4).

Fig. 1
figure 1

Sagittal oblique T1-weighted fast spin echo image with chemical fat saturation and intravenous gadolinium reveals heterogeneous enhancement of a mass within the infrascapular region (arrow)

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Fig. 2
figure 2

The tumor was composed of short, intersecting fascicles of spindle cells with scattered small lymphocytes (original magnification, ×400)

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Fig. 3
figure 3

At high power, the majority of tumor cells demonstrated fusiform pale eosinophilic cytoplasm and elongated, blunt-ended nuclei (original magnification, ×400). These cells were strongly positive for the smooth muscle marker h-caldesmon by immunohistochemistry (not shown)

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Fig. 4
figure 4

In situ hybridization for the LANA gene showed expression in smooth muscle cells and lymphocytes (original magnification, ×200)

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