Malignant effusions from extranodal NK/T‐cell lymphomas are frequently of anaplastic morphology with azurophilic granules and of T‐cell lineage

Abstract

Background Extranodal natural killer/T‐cell lymphoma (ENKTL) nasal type is an extranodal lymphoma, with most cases arising from the prototypic nasal/upper aerodigestive tract and the cell of origin (COO) is frequently of NK cells. Effusion involvement by ENKTL is rare. The cytomorphological and immunophenotypical features and COO of effusion ENKTL are elusive. Design We report four new cases of effusion ENKTL, reviewing the cytomorphological features and investigating their COO by immunohistochemistry for T‐cell receptor (TCR) protein expression and clonality assay for TCR gene rearrangement. We also reviewed 12 additional cases of effusion ENKTL from the literature. Results All our four cases showed anaplastic tumor cells with fine to coarse azurophilic granules, with the primary tumor organs from the prototypic sites (2), small intestine (1), or indeterminate (1). The COO was either T‐cell (3) or NK‐cell (1). Compiling our four cases with that from the literature, all 16 effusion ENKTL cases were Epstein‐Barr virus‐associated and the majority (83%; 10/12) originated from the nonprototypic sites. Five of six (83%) effusion ENKTL cases were of T‐cell lineage. Prognosis was poor with a median survival time of only 2.4 months. Conclusions Our study revealed that ENKTL in the effusion might be characterized by anaplastic large cell morphology, cytoplasmic azurophilic granules, and a higher proportion of T‐cell lineage as compared to de novo tumors arising from the prototypic sites. ENKTL rarely presented in effusion, which is associated with dismal outcome. Large international studies are warranted to validate these findings.

Lymphomatous effusion of monomorphic epitheliotropic intestinal T‐cell lymphoma is characterized by azurophilic granules and is a dismal sign: Report of two new cases with literature review

“…One unusual finding in our case 1 is the azurophilic granules with the Wright‐Giemsa stain. In our recent report of extranodal NK/T‐cell lymphoma with malignant effusion, the neoplastic cells also processed azurophilic granules in the Romanosky‐type stains, such as Giemsa, Diff‐Quik, Wright or Liu stains, but not in Papanicolaou stain 12 . This phenomenon is present in the normal counterparts of cytotoxic T lymphocytes or NK cells, seen as large granular lymphocytes in the peripheral blood.…”

Extranodal NK/T-Cell Lymphoma Predominantly Composed of Anaplastic Cells

“…For example, cases with a predominant small-cell morphology may be mistaken for chronic inflammation 11 . Neoplastic cells with anaplastic morphology have been observed in the malignant effusions of ENKTL patients, as reported by Liu et al 12 However, the clinical and histopathologic features of ENKTL, characterized by the predominance of anaplastic cells have not been previously reported.…”