Diagnosis, prognosis and clinical treatment of refractory atypical chronic lymphocytic leukemia with multiple B cells: A case report.

Background: Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is the most prevalent adult leukemia, and its incidence continues to rise year after year. Rapid and precise diagnosis is an essential element in effective case management, however, the clinical diagnosis, treatment, and prognosis of CLL/SLL are not fully elucidated. Case presentation: we report the case of a 66-year-old man with atypical CLL/SLL. The white blood cell (WBC) count (842.0 × 109/L), platelet count (30.6 × 109/L), and abnormal lymphocytes were increased in peripheral blood. Flow cytometry showed 98.34% of nucleated cells were malignant monoclonal mature B cell. Peripheral blood smear found the leukocytes and lymphocytes with abnormal morphology were increased. Fluorescence in situ hybridization showed CCND1 (11q23)/IGH (14q32) and abnormal chromosome 12 were invisible, 91%-93% of interphase nuclei presented D13S319 and TP53, 17p13.1 loss. Histopathology analysis of bone marrow observed the proliferation centers with immunoblasts. Immunohistochemistry showed that bone marrow was positive for PAX-5, CD20, CD23, and CD5, negative for CD3, cyclinD1, and sox11, and partial positive for Ki67. The patient was diagnosed as CLL/SLL based on above clinical and laboratory ndings. The patient was managed with oral 50 mg Vinetoc, uid replacement, hydration and alkalinization, and the symptoms were signicantly relieved. Conclusions: This report further expands the knowledge of clinical diagnosis and treatment of atypical CLL/SLL. CLL/SLL: Chronic lymphocytic leukemia/small lymphocytic lymphoma; WBC: white blood cell; FISH: Fluorescence in situ hybridization; CBC: complete blood count; PLL: prolymphocytic leukemia; RMH: Royal Marsden Hospital.

A 66-year-old man was admitted to our hospital because of two-month history of asthenia, night sweats, vomiting, and hepatosplenomegaly. Presenting white blood cell (WBC) showed 842.0×10 9 /L, 91 g/L hemoglobin, and 88×10 9 /L platelet count. Microscopic examination of peripheral blood smears observed abnormal lymphocytes was present in 95%. The serum biochemical indices of the patient (Supplementary Table S1) showed β2-microglobulin 5127.59 ug/L. Peripheral blood smear (Fig 1A) showed that the abnormal leukocytes and lymphocytes were markedly increased. Approximately 93% of the cells were prolymphocytes (green arrow) with large cell bodies, round or irregular nuclei, ccumulated chromatin, obvious nucleoli. We also found 7% of immunoblast (yellow arrow) and small lymphocytes (red arrow, <1%). In the French American British classi cation [5], prolymphocytes ≥55% were considered as prolymphocytic leukemia (PLL), but morphological analysis observed the cell body of low proportion cells was smaller than that of CLL cells with normal lymphocytes. observed large cells with median nucleoli (i.e., paraimmunoblast) in proliferation centers, small chronic lymphocytes with deeply stained in the periphery. Immunohistochemistry (Fig 1C) found that bone marrow was positive for PAX-5, CD20, CD23, and CD5,and partially Ki67(30%), negative for CD3, cyclinD1, and sox11.
Flow cytometry (Fig 2A) of peripheral blood showed that 98.34% of nucleated cells was malignant monoclonal mature B cell with heterogeneous cell size. They expressed CD19, CD5, kappa bri, CD20, CD79b bri, CD25, sIgM bri, CD200, CD23, CD11c, and CD49d, and partially FMC7. PLL cells usually has CD5-CD23-FMC7+ immunophenotype, which is different from CLL cells. CLL can't transform into PLL, and the increase of precursor cell only indicates the increased progression of CLL, which often accompanied by NOTCH1 or TP53 aberration [6]. Therefore, although prolymphocytes accounted for 93% in this patient, the possibility of PLL was still excluded. The Royal Marsden Hospital (RMH) score is used for the diagnosis of CLL/SLL by ow cytometry [7]: CD5+, CD23+, FMC7-, CD79b dim or CD22dim, monoclonal kappa/lambda dim or sIg dim. For this patient, the RMH score was 3-4, the atypical chronic lymphocytic, atypical mantle cell lymphoma, and other CD5 + small B-cell lymphomas cannot be excluded by 3-4 score and strong positive expression of CD200 [8,9].
It has been reported that the gene expression (unmutated immunoglobulin heavy-chain variable gene, CD38, CD49d, ZAP-70), trisomy 12 abnormalities, 11q-, 13q-, 6q-, 17p-or TP53 mutations, and serum β2microglobulin deposition are associated with CLL progression and poor prognosis [10]. In this case, this patient expressed CD49d, which is a poor predictor of CLL and involved in tumor invasion [11]. In this patient, including D13S319 loss, TP53 gene loss, higher Ki67 positive rate, signi cant myeloproliferative centers, and cell transformation, and β2-microglobulin up to 5127.59 ug/L,were observed as factors indicating poor prognosis.
The patient was diagnosed with CLL/SLL (BinetC, RaiIV; IPI7 polarization) and initially managed with BR regimen (bendamustine 90 mg/m2 combined with Mabthera 375 mg/m2), but this therapy was ineffective. Then, he was treated with oral 50 mg Vinetoc, and uid replacement, hydration and alkalinization were performed to monitor changes in the condition. After 5 days, the patient had no fever, nausea, vomiting or other discomfort. His general state is good, aphemia, spleen was reduced and no palpable in pleura; WBC, 51.0 × 10 9 /L. After 15 days, the WBC decreased to 25.0 × 10 9 /L, the symptoms were signi cantly relieved.
In conclusion,this study elaborated the diagnosis, prognosis, and clinical standardized treatment of CLL/SLL, and illustrated the signi cance and value of complete MICM diagnosis.