Search for a command to run...
Fifty-nine-year-old male with a history of primary CD30+ cutaneous T-cell lymphoma (CTCL) presented with difficulty in eating and a mass at the base of the tongue. Biopsy demonstrated atypical lymphoid infiltrate composed of medium to large-sized lymphocytes with irregular nuclear contours, vesicular chromatin, prominent nucleoli, and a moderate amount of cytoplasm (Figure 1A). Flow cytometric analysis showed an abnormal lymphocyte population (Figure 1B) that was unequivocally CD19+ (Figure 1C) and predominantly CD5− (small subset positive) (Figure 1D), suggestive of a B-cell lymphoma. However, further analysis showed the entire CD19+ population was also brightly positive for CD3, CD7, CD8, and CD2 (Figure 1E–G). This population was clonal based on TRBC1 expression (TRBC1−) (Figure 1H). Immunohistochemistry confirmed the lymphoma was positive for CD19 (Figure 2A), CD3 (Figure 2B), CD8 (Figure 2C), BetaF1, and TIA1, while negative for CD30, CD20 (Figure 2D), and other B-cell markers including PAX5 (Figure 2E), CD22, CD79a, and OCT2. The possibility of a composite lymphoma or dual cell population was considered; however, flow cytometric analysis revealed a single abnormal cell population that showed co-expression of CD19, CD3, CD8, and multiple T-cell markers and was negative for CD20 and surface kappa or lambda light chain (not shown). Tissue immunohistochemical evaluation confirmed the flow cytometry findings. Therefore, the possibility of composite B/T cell lymphoma is excluded. PCR studies were positive for clonal TCR-beta gene rearrangement and negative for clonal IgH gene rearrangement. A diagnosis of peripheral T-cell lymphoma, NOS, cytotoxic subtype, with aberrant CD19 expression was established. It is not clear whether this lymphoma represents a transformation of the prior CD30+ CTCL or a separate T-cell lymphoma as we do not have TCR gene rearrangement data from the prior CD30+ CTCL from 2019 to confirm if they are clonally related. But immunophenotypically, this lymphoma is very different from that of the prior CTCL, which was CD30+, CD4+, CD8−, and CD7−. The lymphoma progressed quickly with extensive involvement of skin, liver, and bone marrow. The patient succumbed to the disease 13 months after this diagnosis despite multiple therapies and hematopoietic stem cell transplant. Expression of B-cell markers such as CD20 on T-cell lymphoma has been described [1, 2], but expression of CD19 on T-cell lymphoma is exceedingly rare [3]. This case illustrates the rare phenomenon of CD19 expression in T-cell lymphoma, which could pose a significant diagnostic challenge. Comprehensive immunophenotypic and genetic evaluations are critical in reaching the correct diagnosis. B.V., Y.L., and Q.C. were responsible for data collection, interpretation, and creating the manuscript. The authors have nothing to report. The authors have nothing to report. The authors have nothing to report. The authors declare no conflicts of interest. The data that support the findings of this study are available from the corresponding author upon reasonable request.