Cutaneous T-cell lymphomas with pathogenic somatic mutations and absence of detectable clonal T-cell receptor gene rearrangement: two case reports

Diagnostic Pathology

Erica Wang¹  Youn H. Kim²  Michael S. Khodadoust²  Rebecca Rojansky³  Sebastian Fernandez-Pol³  Christian A. Kunder³  Roberto A. Novoa⁴  Kerri E. Rieger⁴  Ryanne A. Brown⁵  James L. Zehnder⁶ 

[1] Department of Dermatology, Stanford Medicine, 94305, Stanford, CA, USA;Department of Dermatology, Stanford Medicine, 94305, Stanford, CA, USA;Division of Oncology, Department of Medicine, Stanford Medicine, 94305, Stanford, CA, USA;Department of Pathology, Stanford Medicine, 94305, Stanford, CA, USA;Department of Pathology, Stanford Medicine, 94305, Stanford, CA, USA;Department of Dermatology, Stanford Medicine, 94305, Stanford, CA, USA;Department of Pathology, Stanford Medicine, 94305, Stanford, CA, USA;Department of Dermatology, Stanford Medicine, 94305, Stanford, CA, USA;Department of Pathology, Veterans Affairs Palo Alto Health Care System, 3375 Hillview Ave, Room 1821, 94304-1204, Palo Alto, CA, USA;Department of Pathology, Stanford Medicine, 94305, Stanford, CA, USA;Division of Hematology, Department of Medicine, Stanford Medicine, 94305, Stanford, CA, USA;

关键词: Lymphoma;    Mycosis fungoides;    T-cell receptor;    Clonality;    Next-generation sequencing, case report;   

DOI  :  10.1186/s13000-020-01022-x

来源: Springer

【 摘 要 】

BackgroundCutaneous T-cell lymphomas (CTCL) are a heterogeneous group of extranodal non-Hodgkin lymphomas for which diagnosis can be challenging given the potential for overlap with inflammatory dermatoses. Current diagnostic criteria for CTCL incorporate clinical and histopathologic findings as well as results of T-cell receptor (TCR) gene sequencing. Molecular interrogation of TCR genes, TRG and TRB, has proven to be a critical tool for confirming diagnoses of CTCL and for disease tracking after initiation of therapy or after stem cell transplant. Methods for confirming a diagnosis of lymphoma in the absence of TCR gene clonality are lacking. We present two patients with CTCL with pathogenic somatic mutations in the absence of TRG and TRB clonality.Case presentationsCase 1: A 38-year-old male had a 19-year history of a diffuse skin rash with papulosquamous, granulomatous, and verrucous features and progressive ulcerated plaques and tumors demonstrating an atypical CD4+ T-cell infiltrate with expression of cytotoxic markers CD56, TIA-1, granzyme, and perforin on histopathology. No definitive evidence for T-cell clonality was detected by conventional PCR of 6 biopsies or by next-generation sequencing (NGS) of 14 biopsies. Somatic mutational profiling of a skin biopsy revealed pathogenic mutations in PIKC3D and TERT promoter hotspots, confirming the presence of a clonal process. Case 2: A 69-year-old male with a 13-year history of progressive, diffuse hypertrophic and eroded plaques showed an atypical CD4+ T-cell infiltrate with subset expression of TIA-1 and granzyme on histopathology. No TCR clonality was detected by TCR-NGS of 6 biopsies. Somatic mutational profiling of a skin biopsy detected a pathogenic mutation in TP53, confirming the presence of a clonal process.ConclusionsThese cases highlight how detection of pathogenic somatic mutations can confirm a diagnosis of lymphoma in a clinically and histopathologically suspicious cutaneous lymphoid proliferation without detectable TCR clonality.

【 授权许可】

CC BY