case_images: PMC6718739_01
case_images: The immunohistochemical staining of the mediastinum mass (magnification, x200). (A) H&E staining. The neoplasm expressed TdT (B), CD7 (C), MPO (E), Ki67 (80%) (F), CD34 (G), CD33 (H), and LCA (I), while it did not express cCD3 (D), CD8 (J), PAX5 (K), and CD1a (L).
case_images: OTT-12-7039-g0001.jpg
case_images: PMC6718739_01_OTT-12-7039-g0001.jpg
case_images: F0001
case_images: S-100- (Figure 1). Since bone marrow was not involved by the analysis of aspiration and biopsy with routine staining and flow cytometry, he was diagnosed as T-LBL with myeloid differentiation.
case_images: The PET-CT imaging of the lesions before and after treatment. In comparison with before treatment (A, B, E, F), the masses disappeared in left cervix, mediastinum, and peritoneal cavity after the completion of therapy (C, D, G, H).
case_images: OTT-12-7039-g0002.jpg
case_images: PMC6718739_01_OTT-12-7039-g0002.jpg
case_images: F0002
case_images: After the pleural effusion was drained, PET-CT scan was performed, which revealed a bulky mass in anterior superior mediastinum (SUVmax 8.1) and many enlarged lymph nodes in bilateral cervical, supraclavicular, subclavian, hilar, axillary, and retroperitoneal regions (SUVmax from 3.0 to 4.6) (Figure 2). After two cycles of treatment, the patient achieved a CR as evaluated by PET/CT scan (Figure 2).
case_images: Flow cytometry analysis of lineage antigens of blast cells in pleural effusion. The blast cells brightly expressed CD7, CD33, CD13, cTdT, CD34, HLA-DR, and CD38, dimly expressed cCD79a, cMPO, and CD123, but did not express cCD3, CD19, CD20, CD117, CD2, CD5, CD8, CD10, CD15, CD16, and CD56.
case_images: OTT-12-7039-g0003.jpg
case_images: PMC6718739_01_OTT-12-7039-g0003.jpg
case_images: F0003
case_images: Flow cytometry analysis of blast cells in the pleural effusion found a single population expressing multi-lineage markers (Figure 3).
case_images: Conal T-cell receptor (TCR) rearrangement of blast cells. Clonal gene rearrangement was observed in TCR beta VJII (A) and TCR delta VD/DD/DJ (B) fragments. In panel (A), the arrow indicates the monoclonal peak of TCR beta VJII. In Panel (B), the arrow indicates the monoclonal peak of TCR delta VD/DD/DJ.
case_images: OTT-12-7039-g0004.jpg
case_images: PMC6718739_01_OTT-12-7039-g0004.jpg
case_images: F0004
case_images: However, clonal TCR gene rearrangement was found, which suggested an origin of T-cell precursor (Figure 4).