SOX11 is useful in differentiating cyclin D1-positive diffuse large B-cell lymphoma from mantle cell lymphoma.

To characterize the frequency and clinicopathological features of cyclin D1-positive diffuse large B-cell lymphoma (DLBCL) and the usefulness of SOX11 in the differential diagnosis from mantle cell lymphoma (MCL). We retrospectively stained 206 consecutive DLBCLs for cyclin D1, and identified three (1.5%) positive cases, comprising two in the elderly with necrosis, and a third with a starry-sky pattern. All three cases shared the same non-germinal centre B-cell (non-GCB) phenotype [CD5-/CD10-/bcl-6+/MUM1+/SOX11-], Epstein-Barr virus (EBV) negativity, and absence of CCND1 aberrations by fluorescence in-situ hybridization. The third case showed both BCL6 and MYC rearrangements: a double-hit lymphoma. In the same period there were 22 MCLs, all expressing cyclin D1, with 89% cases expressing SOX11, a frequency that is statistically different from cyclin D1-positive DLBCL. Notably, we identified a pleomorphic MCL initially misdiagnosed as DLBCL. A separate cohort of 98 DLBCL cases was negative for SOX11, with only one case expressing cyclin D1 with a GCB phenotype (CD10+/bcl-6+/MUM1-). The two patients with tumour necrosis rapidly died of disease. The other two were in complete remission after immunochemotherapy. Cyclin D1-positive DLBCLs are rare, and they are negative for SOX11 or CCND1 aberration. SOX11 is useful in differentiating cyclin D1-positive DLBCL from MCL.

Hsiao SC ，Cortada IR ，Colomo L ，Ye H ，Liu H ，Kuo SY ，Lin SH ，Chang ST ，Kuo TU ，Campo E ，Chuang SS ... -  《-》

Identification of CD5/SOX11 double-negative pleomorphic mantle cell lymphoma.

Cyclin D1 protein-positive diffuse large B cell lymphoma (DLBCL) has an immunophenotype of CD5(-) cyclin D1(+) SOX11(-), and most cases lack a CCND1 rearrangement and have a gene expression profile of DLBCL. Rarely, cyclin D1 protein-positive DLBCL harbors a CCND1 rearrangement, and some genetic copy number features typical of mantle cell lymphoma (MCL) have been detected. Since gene expression studies have not been performed, whether such CCND1-rearranged cases represent cyclin D1 protein-positive DLBCL or CD5/SOX11 double-negative pleomorphic MCL remains unclear. To date, no cases of CD5/SOX11 double-negative MCL have been reported. In this study, we collected eight cases initially diagnosed as cyclin D1 protein-positive DLBCL, including four with a CCND1 rearrangement and four without. Immunohistochemically, all four CCND1-rearranged cases had >50% of tumor cells positive for cyclin D1 protein, whereas only one (25%) non-rearranged case had >50% positive tumor cells. Analysis of genome-wide copy number, mutational, and gene expression profiles revealed that CCND1-rearranged cases were similar to MCL, whereas CCND1-non-rearranged cases resembled DLBCL. Despite the SOX11 negativity by immunohistochemistry, CCND1-rearranged cases had a notable trend (P = 0.064) of higher SOX11 mRNA levels compared to non-rearranged cases. Here, we show for the first time that CCND1 rearrangement could be useful for identifying CD5/SOX11 double-negative pleomorphic MCL in cases diagnosed as cyclin D1 protein-positive DLBCL. Cases with >50% cyclin D1 protein-positive tumor cells immunohistochemically and higher SOX11 mRNA levels are more likely to have a CCND1 rearrangement, and fluorescence in situ hybridization can be used to detect the rearrangement.

Chuang WY ，Chang H ，Shih LY ，Lin TC ，Yeh CJ ，Ueng SH ，Kuo MC ，Kao HW ，Liu H ，Chang ST ，Lee CL ，Huang KP ，Wang TH ，Wan YL ，Yu JS ，Hsueh C ，Chuang SS ... -  《-》

Cyclin D1-positive diffuse large B-cell lymphoma with IGH-CCND1 translocation and BCL6 rearrangement: a report of two cases.

To demonstrate and confirm the existence of cyclin D1-positive diffuse large B-cell lymphoma (DLBCL) with IGH-CCND1 rearrangement and discuss the rationale of differentiating this entity from blastoid and pleomorphic variants of mantle cell lymphoma (MCL). Two cyclin D1-positive lymphomas with morphologic features of DLBCL and IGH-CCND1 translocations were characterized with respect to clinical features, as well as morphologic, immunophenotypic, cytogenetic, and molecular findings. The large tumor cells were CD20+, CD5-, CD10-, BCL6+, MUM1+, and cyclin D1+ in both cases. SOX11 was negative. Epstein-Barr virus-encoded RNA in situ hybridization demonstrated diffuse positivity in case 1. BCL6 and IGH-CCND1 rearrangements were identified by fluorescence in situ hybridization in both cases. Specifically, the diagnosis of a relapsed DLBCL with acquisition of IGH-CCND1 was rendered for case 1, molecularly confirmed by the detection of identical monoclonal IGH rearrangements between the initial diagnostic DLBCL and relapse lymphoma. Our study demonstrates convincingly that IGH-CCND1 rearrangement leading to cyclin D1 overexpression can occur in DLBCL and pose a potential diagnostic pitfall, requiring thorough knowledge of the clinicopathologic findings to allow accurate discrimination from a blastoid or pleomorphic MCL. The coexistence of IGH-CCND1 and IGH-BCL6 rearrangements suggest that BCL6 and cyclin D1 may cooperate in the pathogenesis of DLBCL.

Al-Kawaaz M ，Mathew S ，Liu Y ，Gomez ML ，Chaviano F ，Knowles DM ，Orazi A ，Tam W ... -  《-》

Pleomorphic mantle cell lymphoma morphologically mimicking diffuse large B cell lymphoma: common cyclin D1 negativity and a simple immunohistochemical algorithm to avoid the diagnostic pitfall.

To characterize the clinicopathological and genetic features of pleomorphic mantle cell lymphoma (PMCL), which morphologically mimics diffuse large B cell lymphoma (DLBCL). We screened systematically 500 B cell lymphomas morphologically compatible with DLBCL using an immunohistochemical algorithm of three markers (CD5, cyclin D1 and SOX11). Ten cases of PMCL were identified for further study and, surprisingly, four (40%) of them were cyclin D1-negative. These 10 patients were mainly elderly males with advanced disease, and their median survival was only 11 months. All cyclin D1-positive PMCLs tested showed an IGH-CCND1 translocation, whereas one of the four cyclin D1-negative PMCLs had a translocation involving CCND2 and a high CCND2 mRNA level (P < 0.000001). The genomewide copy number profiles of both cyclin D1-positive and cyclin D1-negative PMCLs were similar to those of classical mantle cell lymphoma (MCL) reported previously, confirming the diagnosis. Secondary genetic alterations involved in oncogenic pathways of MCL were observed more frequently in these PMCLs, possibly decreasing the dependence on the driving CCND1 translocation and accounting for the common cyclin D1 negativity. Copy number gains of PIK3CA and CCDC50 were detected in all cyclin D1-negative PMCLs but in only 40% of the cyclin D1-positive PMCLs. These additional oncogenic signals may compensate for the common absence of CCND2 translocation in cyclin D1-negative PMCL. We demonstrate for the first time that cyclin D1 negativity is surprisingly common in PMCL morphologically mimicking DLBCL, and the use of a simple immunohistochemical algorithm can prevent misclassification and inappropriate treatment.

Chuang WY ，Chang H ，Chang GJ ，Wang TH ，Chang YS ，Wang TH ，Yeh CJ ，Ueng SH ，Chien HP ，Chang CY ，Wan YL ，Hsueh C ... -  《-》

Identification of CD5/Cyclin D1 Double-negative Pleomorphic Mantle Cell Lymphoma: A Clinicopathologic, Genetic, and Gene Expression Study.

Chuang WY ，Chang ST ，Yuan CT ，Chang GJ ，Chang H ，Yeh CJ ，Ueng SH ，Kao HW ，Wang TH ，Wan YL ，Shih LY ，Chuang SS ，Hsueh C ... -  《-》