PMC4336419_01
Contrast-enhanced computed tomography (CT) of the pelvis demonstrating the left gluteal mass (arrow). (A) CT showed a non-uniformly enhancing hypervascular mass with central necrosis in the left gluteal muscle. (B) The tumor demonstrated adjacent bone involvement with destruction of the sacroiliac joint.
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C-reactive protein (CRP). Contrast-enhanced computed tomography (CT) scan of the pelvis revealed a non-uniformly early enhancing mass, approximately 51 x 64 mm in size, in the left gluteal muscle (Fig. 1A). The tumor demonstrated central necrosis and adjacent bone involvement, with destruction of the sacroiliac joint (Fig. 1B).
Fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT images. (A) Axial 18F-FDG PET/CT view demonstrated large areas of increased 18F-FDG uptake in the left gluteal musculature [maximum standard uptake value (SUVmax) = 34], the posterior aspect of the left ileum (arrow) and the sacrum. (B) Whole-body 18F-FDG PET/CT identified strong 18F-FDG uptake by the para-aortic and mediastinal lymph nodes (arrow), and faint scattered 18F-FDG uptake by both lungs (SUVmax = 3.8).
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Fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET)/CT demonstrated a large area of increased 18F-FDG uptake in the left gluteal musculature [maximum standard uptake value (SUVmax) = 34], the posterior aspect of the left ileum and the sacrum (Fig. 2A). Whole-body 18F-FDG PET/CT identified intense 18F-FDG uptake by the para-aortic and mediastinal lymph nodes, and faint scattered 18F-FDG uptake by both lungs (Fig. 2B).
Histological and immunohistochemical examination of the resected specimen of the left buttock. (A) Hematoxylin and eosin (H-E) staining revealed diffuse infiltration with large atypical lymphoid cells with prominent nucleoli (x400). (B) CD20 immunohistochemical staining demonstrated the presence of large atypical lymphoid cells on the membrane (x400).
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Pathological studies of the specimen demonstrated dense and diffuse infiltration and proliferation of large atypical lymphoid cells, accompanied by small lymphocytes (Fig. 3A). Immunohistochemical studies showed that the large atypical lymphoid cells were positive for LCA, CD20 and bcl-6, and were negative for cytokeratin, S-100, alpha-SMA and bcl-2 (Fig. 3B).
Contrast-enhanced CT of the pelvis after chemotherapy. (A) CT showed the mass in the left gluteal muscle has completely disappeared (arrow). (B) CT showed the erosion of the sacroiliac joint still remained (arrow), showing the destructive characteristics of the tumor.
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IV DLBCL, low-intermediate risk of the international prognostic index (IPI). Immediately after diagnosis, the patient has received 8 cycles of R-CHOP chemotherapy, and as a result the mass in the left gluteal muscle has completely disappeared (Fig. 4A, B).