Flow Cytometry-Guided Diagnosis of Cortical T-Lymphoblastic Lymphoma Presenting With a Massive Mediastinal Mass and Borderline Bone Marrow Involvement.
Chen Glait-Santar, Yakir Moshe, Itzhaki-Alfia Ayelet et al.
✦ AI-curated · Sources linked
Case in brief
A 57-year-old man presented with dyspnea, a large mediastinal mass causing superior vena cava syndrome, and pleural and pericardial effusions. Cytology and biopsy showed a diffuse blastoid lymphoid infiltrate. Pleural-fluid flow cytometry identified an aberrant immature T-cell population with a cortical phenotype, supporting T-lymphoblastic lymphoma. Although marrow morphology suggested approximately 10% blasts, flow cytometry found 3.8% CD34+ cells with a myeloid-skewed, non-T-lymphoblastic phenotype, arguing against significant marrow involvement. He was classified as having T-LBL, treated according to the GMALL protocol, and achieved complete remission.
What made this case unusual
The borderline marrow blast estimate conflicted with flow cytometry, which showed no significant T-lymphoblastic marrow involvement; resolving this discrepancy avoided classifying the predominantly extramedullary disease as T-ALL.
Diagnostic / clinical pearl
In precursor T-cell neoplasms with borderline marrow blast counts, multiparameter flow cytometry can clarify lineage and marrow involvement when morphology alone is inconclusive.