PMC3437912_01
Gross findings of the primary lesion. A 6.5 cm x 4.0 cm tumor (A) was observed in the terminal ileum (arrows). The tumor was elevating and had a subpedunculated feature (B).
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Grossly, the lesion in the terminal ileum was a 6.5 cm x 4.0 cm subpedunculated, elevating tumor (Figure 1).
Histopathological findings. In the primary lesion (A), the tumor showed consistent with plasmacytoma. In some areas of the primary lesion (B), plasmablastic lymphoma-like features were observed. In the regional lymph nodes (C), involvement by plasmacytoma cells was observed (D). EBER in situ hybridization showed the tumor cells were positive. MIB-1 (Ki-67) labeling index of the tumor cells (E) was approximately 80%-90%. Primary lesion (F) was negative. Lymph node lesion (G) was positive.. Notes: Original magnification of (A-G): x400. (A-C) resulted from HE staining, (F and G) from CD20 immunostaining.. Abbreviations: EBER, Epstein-Barr virus-encoded small nuclear RNA; HE, hematoxylin and eosin.
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Histopathologically, the tumor showed solid growth of prominent nonepithelial cells with eccentrically located nuclei and clear perinuclear cytoplasm (CD138+), consistent with extraosseous plasmacytoma (Figure 2A). In some areas, features compatible with those of PBL, such as plasmablast-like cells and mitotic figures, were observed (Figure 2B). In the dissected regional lymph nodes, there was a proliferation of tumor cells similar to those in the ileal lesion, which included PBL components, suggesting lymph node involvement (Figure 2C). Tumor cells were positive for EBV-encoded small nuclear RNA in in situ hybridization (Figure 2D). The MIB-1 (Ki-67) labeling index of the plasmablast-like tumor cells was approximately 80%-90% (Figure 2E). Tumor cells of the ileum were negative for CD20 (Figure 2F), whereas atypical, large and clear cells of the lymph node lesions were positive for CD20 (Figure 2G).
Abdominal computed-tomography findings. (A) The abdominal lymph nodes (indicated by arrow) were observed. (B) The lymph nodes disappeared after R-CHOP chemotherapy.. Abbreviation: R-CHOP, rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone.
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Computed-tomography scans performed at 6 months showed the swelling of several abdominal lymph nodes, such as the para-aortic and mesenteric lymph nodes, which were not seen at surgery, suggesting abdominal lymph node recurrence (Figure 3A). At the end of 3 cycles of R-CHOP, complete remission (CR) was evaluated by computed-tomography imaging (Figure 3B), and the beta2-microglobulin and sIL-2R levels returned to their normal ranges.