A previously healthy 27-year-old male first presented to the outpatient department in Tongji Hospital due to right testis swelling and scattered skin erythema onset for approximately 1 month. There were no other concomitant symptoms, such as fever, night sweat, or loss of weight. On physical examination, painless enlargement of submandibular and cervical lymph nodes was palpable. Then, he was admitted to our department for further diagnosis and treatment.
Routine laboratory evaluation demonstrated normal white blood cell (WBC) counts and hemoglobin and mildly increased platelet counts [376.0*109/L (normal: 150-350*109/L)], lactate dehydrogenase [234 U/L (normal:135-225 U/L)] and beta2 microglobulin [2.76 mg/L (normal:0.8-2.2 mg/L)]. Serology tests were negative for HIV, HBV, CMV and EBV infection. An abdominal ultrasound did not indicate hepatomegaly or splenomegaly. Bone marrow smear and histology revealed normal morphological, immunological flow cytometric (FCM), cytogenetic and molecular (MICM) results. No central nervous system infiltration was detected by cerebrospinal fluid flow cytometry. However, positron emission tomography/computed tomography (PET/CT) scans demonstrated abnormally increased metabolic activity in multiple lymph nodes (SUV max: 9.4), bones (right clavicle, left scapula, left 2nd rib, right accessory of 11th thoracic vertebra, 1st-2nd lumbar vertebra, bilateral femurs and bilateral superior tibial segment; SUV max: 6.2), the posterior walls of the nasopharynx (SUV max: 6.5), the bilateral ethmoid sinuses (SUV max: 5.0), and the bilateral testicular and right spermatic cords (SUV max: 7.3). There was also mildly increased metabolic activity in the subcutaneous nodules on the bilateral cheeks (SUV max: 2.8) (Figure 1A and B). The patient underwent ultrasound-guided fine-needle aspiration in the left enlarged supraclavicular lymph node. The pathological biopsy specimen was extensively replaced with tumor cells characterized by distinct nucleoli and scant cytoplasm. Immunohistochemical staining showed that representative B lymphoblastic tumor cells were positive for CD20 and terminal deoxynucleotidyl transferase (TdT) and negative for CD3, and approximately 90% of the neoplastic cells displayed nuclear Ki67 staining (Figure S1). Meanwhile, the cutaneous biopsy, also revealed consistency of the phenotype of the B lymphoblasts, were positive for CD20, CD19, PAX5, TDT, CD10, CD38, C-MYC, CD99, BCL-2 and CD43, but negative for CD3, CD34, CD7, BCL-6, MPO and MUM1, and Ki67 staining about 90% (Figure 2). Therefore, the diagnosis of B-LBL (Ann Arbor stage IIIA, IPI 3 scores) was confirmed.
To control lymphoma in a timely manner, the patient received the high-risk chemotherapy protocol of CCCG-LBL-2016 (Induction I with prednisone, vincristine, daunorubicin, PEG-LASP, cyclophosphamide, cytarabine, 6-mercaptopurine plus prophylactic intrathecal infusion from Day 1 to Day 63). RNAseq, with reference to the GRCh37/hg19 genome and mainly to detect genetics disruption at the level of the human transcriptome, was performed on the left supraclavicular lymph node specimens as a part of routine diagnostic workup in our institution. Unexpectedly, IKZF1 deletions and BCR-ABL1 fusion transcripts were detected approximately 3 weeks after chemotherapy. Based on these results, we retrospectively validated BCR/ABL1 rearrangement in previous lymph node biopsy specimens by fluorescence in situ hybridization (FISH), which detected a 70% positive signal (Figure 3). Given that the modified diagnosis turned to Ph+ B-LBL, a combination of dasatinib (140mg, qd) was added to therapeutic regimen. PET/CT evaluation was carried out before Protocol M of CCCG-LBL-2016 began, and it showed complete remission (CR) (Figure 1C and D), Protocol M (5 g/m2 methotrexate and 6-mercaptopurine) combined with dasatinib proceeded as planned for 4 cycles. Then, the patient finally underwent allogeneic transplantation with granulocyte colony-stimulating factor-mobilized bone marrow cells plus peripheral blood hematopoietic stem cells from his father, who was mismatched for five loci in March 2021. He received a TBI/VP/CY/ATG conditioning regimen consisting of total body irradiation (Day -9), etoposide (15 mg/kg/day on Days -8 and -7), cyclophosphamide (1.8 g/m2/day on Days -6 and -5), and ATG (thymoglobulin, 2.0 mg/kg/day on Days -4 to -1). The procedure was well tolerated, and he achieved successful engraftment on Day 15 post-stem cell infusion (SCI). He did not undergo any grade of acute or chronic graft-versus-host disease (GVHD) but only had temporary and asymptomatic Epstein-Barr virus (EBV)-reactivated viremia. All immunosuppressants were tapered and stopped within 2 months after SCI, and he took dasatinib 50 mg daily for maintenance. Monthly follow-ups were regularly performed, including the monitoring of bone marrow chimerism and BCR/ABL1 copies by polymerase chain reaction amplification of short tandem repeats (PCR-STR) and RT-PCR, respectively. Sustained complete chimerism and negative BCR/ABL1 detection, along with recent PET/CT results (Figure 1E and F), indicated a satisfactory CR for more than 1 year.