Diffuse Large B-Cell Lymphoma With Striking Intrasinusoidal Pseudoglandular Growth Pattern as a Diagnostic Dilemma Mimicking Metastatic Poorly Differentiated Pancreatic Adenocarcinoma in an Intraabdominal Lymph Node

Plastin-3 is a diagnostic and prognostic marker for pancreatic adenocarcinoma and distinguishes from diffuse large B-cell lymphoma

Background

Altered Plastin-3 (PLS3; an actin-binding protein) expression was associated with human carcinogenesis, including pancreatic ductal adenocarcinoma (PDA). This study first assessed differentially expressed genes (DEGs) and then bioinformatically and experimentally confirmed PLS3 to be able to predict PDA prognosis and distinguish PDA from diffuse large B-cell lymphoma.

Methods

This study screened multiple online databases and revealed DEGs among PDA, normal pancreas, diffuse large B-cell lymphoma (DLBCL), and normal lymph node tissues and then focused on PLS3. These DEGs were analyzed for Gene Ontology (GO) terms, Kaplan–Meier curves, and the log-rank test to characterize their association with PDA prognosis. The receiver operating characteristic curve (ROC) was plotted, and Spearman’s tests were performed. Differential PLS3 expression in different tissue specimens (n = 30) was evaluated by reverse transcription quantitative polymerase chain reaction (RT-qPCR).

Results

There were a great number of DEGs between PDA and lymph node, between PDA and DLBCL, and between PDA and normal pancreatic tissues. Five DEGs (NET1, KCNK1, MAL2, PLS1, and PLS3) were associated with poor overall survival of PDA patients, but only PLS3 was further verified by the R2 and ICGC datasets. The ROC analysis showed a high PLS3 AUC (area under the curve) value for PDA diagnosis, while PLS3 was able to distinguish PDA from DLBCL. The results of Spearman's analysis showed that PLS3 expression was associated with levels of KRT7, SPP1, and SPARC. Differential PLS3 expression in different tissue specimens was further validated by RT-qPCR.

Conclusions

Altered PLS3 expression was useful in diagnosis and prognosis of PDA as well as to distinguish PDA from DLBCL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-021-02117-1.

The clinicopathological and molecular features of sinusoidal large B-cell lymphoma

We report 17 cases of sinusoidal large B-cell lymphoma (SLBCL). Clinical, morphologic, immunophenotypic, and molecular features were detected and analyzed. All cases showed an obvious sinusoidal growth pattern, usually associated with residual atrophic lymphoid tissue. All tumors contained large pleomorphic lymphoid cells and one or more prominent nucleoli, with abundant amphophilic cytoplasms; 15/17 cases showed anaplastic morphologic features. The patient age ranged from 43 to 80 years (median 57 years), and 7 males and 10 females were included. Eleven of 15 (73.3%) patients had Ann Arbor stage III or IV disease, and 10/15 (66.6%) patients had an International Prognostic Index (IPI) score ≥3. Immunophenotypically, 16/17 (94.1%) cases displayed a nongerminal center B-cell (non-GCB) immunophenotype. Furthermore, 16/17 (94.1%) cases were positive for CD30, and p53 was expressed in 10/16 (62.5%) cases. In total, 12/14 (85.7%) cases expressed BCL2 and MYC simultaneously (double expression), and 11/14 (78.6%) cases showed PD-L1 positivity (6/11 had a PD-L1 tumor proportion score ≥50%). Cytogenetically, concurrent MYC and BCL2 and/or BCL6 abnormalities (break-apart or extra copy) were detected in 10/15 cases, and 7/13 (53.8%) cases harbored a PD-L1/L2 amplification. TP53 mutation was found in 7/13 (53.8%) cases by Sanger sequencing. Whole-exome and large-panel sequencing results revealed high mutation frequencies of TP53 (4/7), MYD88 (3/7), KMT2D (3/7), CREBBP (3/7), and PIM1 (3/7). Among the 13 patients with SLBCL treated with aggressive chemotherapy regimens, the median overall survival (OS) was 18 months, and the 2-year OS rate was 34.6%. The OS of patients with SLBCL was markedly worse than that of 35 control group patients with common diffuse large B-cell lymphoma (DLBCL) without sinusoidal features (P < 0.001). SLBCL may represent a specific type of DLBCL that has characteristic pathologic features. The cancer is aggressive in most clinical cases, and outcomes are poor. SLBCL and anaplastic DLBCL (A-DLBCL) have many overlapping clinicopathological and molecular features.