Malignant Lymphoma in the Psoas Major Muscle

Figure 2

Histopathological examination of a biopsy specimen from the right back mass. (a) Low-power view (×100) and (b) high-power view (×400) of the biopsy specimen obtained from the right back mass, stained with hematoxylin and eosin, showed diffuse infiltration of medium-sized atypical lymphocytes into the interstitium of the striated muscle. Immunohistochemical staining with (c) anti-CD3, (d) anti-CD5, (e) anti-CD10, (f) anti-CD20, and (g) anti-BCL-2 antibodies. CD3- and CD5-positive cells were interspersed among atypical lymphocytes, but CD20-positive cells were obviously predominant. These atypical lymphocytes were CD10-negative and weakly BCL-2-positive.

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