Clinicopathologic Spectrum of Gastrointestinal T-cell Lymphoma: Reappraisal Based on T-cell Receptor Immunophenotypes. Am J Surg Pathol. 2016;40:777-785. [PMID: 26975035 DOI: 10.1097/pas.0000000000000630]

Nodal EBV+ cytotoxic T-cell lymphoma: A literature review based on the 2017 WHO classification

Nodal Epstein-Barr virus (EBV)-positive cytotoxic T-cell lymphoma (CTL) is a primary nodal peripheral T-cell lymphoma (PTCL) characterized by a cytotoxic phenotype and EBV on the tumor cells. This disease reportedly accounts for 21% of PTCL not otherwise specified (NOS). However, few nodal EBV+ lymphomas have been documented in detail. Nodal EBV+ CTL and nasal-type NK/T-cell lymphoma (NKTL) both exhibit cytotoxic molecule expression and EBV positivity on the tumor cells; however, nodal EBV+ CTL is characterized as a systemic disease without nasopharyngeal involvement, and exhibits a CD8+/CD56− phenotype distinct from NKTL. The clinicopathological uniqueness of nodal EBV+ CTL is further supported by its T-cell origin in most reported cases. In the 2008 WHO classification, it was unclear whether nodal EBV+ CTL should be classified as PTCL or NKTL. However, based on additional data, the 2017 revision classifies nodal EBV+ CTL as PTCL. In the present review, we focus on the clinicopathological characteristics of nodal EBV+ CTL, discuss the relationship between chronic active EBV infection and nodal EBV+ lymphoma, and highlight future perspectives regarding the treatment of this disease.

PD-L1 expression on tumor or stromal cells of nodal cytotoxic T-cell lymphoma: A clinicopathological study of 50 cases

Inhibitors of programmed cell-death 1 (PD-1) and programmed cell-death ligand 1 (PD-L1) have revolutionized cancer therapy. Nodal cytotoxic T-cell lymphoma (CTL) is characterized by a poorer prognosis compared to nodal non-CTLs. Here we investigated PD-L1 expression in 50 nodal CTL patients, with and without EBV association (25 of each). We identified seven patients (14%) with neoplastic PD-L1 (nPD-L1) expression on tumor cells, including three males and four females, with a median age of 66 years. One of the seven cases was TCRαβ type, three were TCRγδ type and three were TCR-silent type. Six of the seven cases exhibited a lethal clinical course despite multi-agent chemotherapy, of whom four patients died within one year of diagnosis. Morphological findings were uniform, with six cases showing centroblastoid appearance. Among nPD-L1+ cases, two of three examined had structural variations of PD-L1 disrupting 3'-UTR region. Notably, all of the TCRγδ-type nodal CTL cases showed nPD-L1 or miPD-L1 positivity (3 and 10 cases, respectively). TCRγδ-type cases comprised 42% of nPD-L1+ cases (P = 0.043 vs. PD-L1- ), and 35% of miPD-L1+ cases (P = 0.037 vs. PD-L1- ). The results indicate that PD-L1+ nodal CTL cases, especially of the TCRγδ type, are potential candidates for anti-PD-1/PD-L1 therapies.

Reappraisal of nodal Epstein-Barr Virus-negative cytotoxic T-cell lymphoma: Identification of indolent CD5+ diseases

Nodal cytotoxic molecule (CM)‐positive peripheral T‐cell lymphoma (CTL) has recently been recognized as a clinicopathologically distinct disease. To further characterize this disease, here we compared 58 patients with Epstein‐Barr virus (EBV)‐negative CTL to 48 patients with EBV‐positive CTL. The two groups did not differ in histopathology, T‐cell receptor (TCR) expression or rearrangement incidences, or survival curves. However, patients with EBV‐negative CTL less frequently showed hepatic involvement (P = .007), B symptoms (P = .020), hemophagocytosis (P = .024), and detectable CD4 (P = .002) and CD5 (P = .009). Univariate and multivariate analyses identified three factors that independently predicted favorable survival, onset age <60 years (P = .002), CD5 expression (P = .002), and mixed morphology (P = .013), TCRαβ was not an independent predictor (P = .30), but was strongly linked with long survivorship among patients younger than 60 years old. A prognostic model incorporating these factors worked well for prognostic delineation, independently of the International Prognostic Index (P = .007 vs P = .082) and Prognostic Index for PTCL (P = .020 vs P = .15). Moreover, this constellation of findings indicated two nodal indolent diseases: CD5⁺TCRαβ (n = 13), and CD5⁺NK‐cell type lacking TCR expression or clonal TCRγ rearrangement (n = 4). The survival curves for these two groups were significantly superior to others (n = 29, P < .001). These diseases appear to be unique in their indolent clinical behavior, and should be managed differently from other diseases.

Identification of T-cell receptor expression in EBV-positive neoplastic cells in extranodal NK/T-cell lymphoma, nasal-type, and comparison with T-cell receptor gene rearrangement by BIOMED-2 assay

The cellular lineage of extranodal NK/T-cell lymphoma, nasal-type (ENKTL), is determined by expression of T-cell receptor (TR) or TR gene rearrangement. In ENKTL, from TR immunohistochemistry, it may often be difficult to decide whether TR-positive cells are tumor cells or not, especially when TR is expressed in a subset of tumor cells. To analyze TR expression pattern and TR rearrangement in T-lineage ENKTL, we performed double immunofluorescence staining for Epstein-Barr virus-encoded small RNAs (EBER)/T-cell receptor (TCR) βF1 and CD56/TCR βF1 in 12 cases of ENKTL that showed TCR βF1 expression in immunohistochemistry. TR gene rearrangement was analyzed using a commercial BIOMED-2 multiplex polymerase chain reaction system. Immunohistochemistry showed that all 12 cases expressed TCR βF1 in a wide range of infiltrating cells from 100% to <1%. Two of them expressed both TCR βF1 and TCR cγM1. EBER/TCR-βF1-positivity was confirmed in 10 cases by double staining. One case failed to show EBER/TCR-βF1-positive cells but showed a CD56/TCR βF1-positive result. Among 12 cases, 5 had poor-quality DNA, 3 of them showed no polymerase chain reaction product, and 2 cases showed nonspecific peak of low height. Five of 7 cases with good DNA quality demonstrated monoclonal TR gene rearrangement. Based on TR expression and TR gene rearrangement, 10 of 12 cases of ENKTL were decided as a T-lineage tumor. In conclusion, because of common TR silence and poor DNA quality, consideration of both immunohistochemistry and TR gene rearrangement is necessary to determine the lineage of ENKTL.

γδ T-Cell Acute Lymphoblastic Leukemia/Lymphoma: Discussion of Two Pediatric Cases and Its Distinction from Other Mature γδ T-Cell Malignancies

Gamma delta (γδ) T-cell antigen receptor (TCR) expression and its related T-cell differentiation are not commonly reported in T-cell acute lymphoblastic leukemia/lymphoma (T-ALL). Here we report two pediatric T-ALL cases and present their clinical features, histology, immunophenotypes, cytogenetics, and molecular diagnostic findings. The first patient is a two-year-old girl with leukocytosis, circulating lymphoblasts, and a cryptic insertion of a short-arm segment at 10p12 into the long-arm segment of 11q23 resulting in an MLL and AF10 fusion transcript, which may be the first reported in γδ T-ALL. She responded to the chemotherapy protocol poorly and had persistent diseases. Following an allogeneic bone marrow transplant, she went into remission. The second patient is an eleven-year-old boy with a normal white cell count, circulating blasts, and a normal karyotype, but without any immature cellular markers by flow cytometric analysis. He responded to the chemotherapy well and achieved a complete remission. These cases demonstrate the diverse phenotypic, cytogenetic, and molecular aspects of γδ T-ALL. Early T-precursor- (ETP-) ALL and their differential diagnosis from other mature γδ T-cell leukemia/lymphomas are also discussed.

Intraepithelial lymphocytes, scores, mimickers and challenges in diagnosing gluten-sensitive enteropathy (celiac disease)

The upper digestive tract is routinely scoped for several causes of malabsorption, and the number of duodenal biopsy specimens has increased notably in the last 10 years. Gluten-sensitive enteropathy (GSE) is an autoimmune disease, which shows an increasing prevalence worldwide and requires a joint clinico-pathological approach. The classical histopathology of GSE with partial or total villous blunting is well recognized, but the classification of GSE is not straightforward. Moreover, several mimickers of GSE with intraepithelial lymphocytosis have been identified in the last 20 years, with drug interactions and medical comorbidities adding to the conundrum. In this review, we report on the normal duodenal mucosa, the clinical presentation and laboratory diagnosis of GSE, the duodenal intraepithelial lymphocytes and immunophenotype of GSE-associated lymphocytes, the GSE mimickers, the differences "across oceans" among guidelines in diagnosing GSE, and the use of a synoptic report for reporting duodenal biopsies in both children and adults in the 21st century.