Syncytial variant of classic Hodgkin lymphoma: Four cases diagnosed with the aid of CD274/programmed cell death ligand 1 immunohistochemistry

Abstract

Although several reports have highlighted neoplastic PD‐L1 (nPD‐L1) expression in classic Hodgkin lymphoma (CHL), some have addressed associations between its expression and detailed histopathologic features. Here we describe four cases of syncytial variant of CHL (SV‐CHL), with and without Epstein–Barr virus (EBV) association, and highlight the diagnostic utility of PD‐L1 (clone SP142) immunohistochemistry. The patients were a 61‐year‐old male, 45‐year‐old male, 85‐year‐old female, and 89‐year‐old female. All presented with cervical or axillary lymphadenopathy, which on biopsy had the established histopathologic features of SV‐CHL with a biphasic pattern of cohesive sheets of large tumor cells and typically scattered distribution of Hodgkin and Reed–Stenberg (HRS) cells. These tumor cells showed identical immunophenotypic findings for CD15, CD30, Fascin, PAX5, OCT2, BOB1 and EBV harboring, regardless of location. The exception was absent or decreased expression of nPD‐L1 from tumor cells in the confluent sheets, contrasting with HRS cell positivity in typical areas of CHL. These findings offer the first suggestion of possible downregulation of nPD‐L1 expression in association with the histopathologic progression of CHL. The results may be relevant for recognizing ‘confluent’ sheets in the diagnostic workup for SV‐CHL.

Histiocytic Sarcoma of Bone Marrow With Partial Cohesive Neoplastic Cells and Hemophagocytosis: a Case Report

“…Moreover, although the association of HS with other lymphocytic leukemia/lymphomas had been frequently reported in recent years, most of which still presented as the noncohesive or single diffuse proliferation cells in biopsy [9][10][11]. The atypical cohesive growth pattern of large neoplastic cells only appeared in several cases of B-cell lymphomas of plasma blastic lymphoma (PBL) [12,13], T-cell lymphomas of anaplastic large cell lymphoma (ALCL) [14,15], other metastatic carcinoma to bone marrow [16] and one case of classic Hodgkin lymphoma (CHL) [17]. Interestingly, in this case, a rare sight that neoplastic cell in tightness cohesive clusters with symplasm morphological was distinctly observed on this bone marrow smear, even accompanying with the hemophagocytosis and EBV infection.…”

Hodgkin Lymphoma: Biology and Differential Diagnostic Problem

“…Previous studies show that the presence of HRS cells is seemingly associated with PD-L1 expression, especially in EBV − CHLs. In the syncytial variant, PD-L1 expression is primarily found in HRS cells, but also rarely in small cohesive tumor cells [ 166 ]. It is currently unclear whether this heterogeneity is derived from genetic heterogeneity or transient expression induced by intracellular signaling, such as JAK/STAT activation.…”

Diagnostic utility of programmed cell death ligand 1 (clone SP142) immunohistochemistry for malignant lymphoma and lymphoproliferative disorders: A brief review

“…Compared with positivity on HRS cells in typical areas of CHL, the difference suggests downregulation of nPD-L1 expression with the histopathological progression of CHL. 19 Hollander et al also reported the decreased expression of PD-L1 in HRS cells in consecutive biopsies of a small subset (10-18%) of CHL cases regardless of the treatment setting, but there was no reference of their histopathological findings. 20 MCCHL usually lacks nodular sclerosis and lacunar cells, although fine interstitial fibrosis may be observed.…”