Herein, we report a case of plasmablastic lymphoma (PBL) and diffuse large B-cell lymphoma (DLBCL) that occurred concurrently in the large intestine. An 84-year-old female presented with a palpable rectal tumor and ileocecal tumor observed on imaging analyses. Endoscopic biopsy of both lesions revealed lymphomatous round cells. Hartmann’s operation and ileocecal resection were performed for regional control. The ileocecal lesion consisted of a proliferation of CD20/CD79a-positive lymphoid cells, indicative of DLBCL. In contrast, the rectal tumor showed proliferation of atypical cells with pleomorphic nuclei and abundant amphophilic cytoplasm, with immunohistochemical findings of CD38/CD79a/MUM1/MYC (+) and CD20/CD3/CD138/PAX5 (–). Tumor cells were positive for Epstein-Barr virus– encoded RNA based on in situ hybridization and MYC rearrangement in fluorescence in situ hybridization analysis. These findings indicated the rectal tumor was most likely a PBL. Sequencing analysis for immunoglobulin heavy variable genes indicated a common B-cell origin of the two sets of lymphoma cells. This case report and literature review provide new insights into PBL tumorigenesis.
Plasmablastic lymphoma(PBL) is a recently described aggressive B-cell neoplasm, which usually manifests as a localized disease of the oral mucosa in individuals infected with human immunodeficiency virus(HIV). Recently, we encountered a case of plasmablastic lymphoma manifesting in the left maxillary sinus and cervical lymph node of a previously healthy HIV-negative man, 48 years of age. we conducted a fine-needle aspiration smear of the cervical lymph node, and this was found to be highly cellular with numerous large cells exhibiting eccentrically positioned nuclei, prominent nucleoli, and moderate quantities of basophilic cytoplasm. A biopsy of the mass in the maxillary sinus evidenced diffuse growth of similar plasmablastic cells. These tumor cells were negative for the leukocyte common antigens, CD20, CD3, CD30, and EMA. However, the cells tested positive for CD79a and CD138/syndecan-1. The tumor cells also exhibited L-light-chain restriction. The Ki-67 proliferation index was measured at almost 100%. The patient was diagnosed with plasmablastic lymphoma. After three cycles of combination chemotherapy and radiotherapy, the patient went into complete remission, and currently remains in this state.