Chronic lymphocytic leukemia/small lymphocytic lymphoma with cyclin D1 positive proliferation centers do not have CCND1 translocations or gains and lack SOX11 expression

Deficiency of miR-155 in Leukemic B-Cells Results in Cell Cycle Arrest and Deregulation of MIR155HG/TP53INP1/CDKN1A/CCND1 network

BACKGROUND

Cell cycle progression and leukemia development are tightly regulated processes in which even a small imbalance in the expression of cell cycle regulatory molecules and microRNAs (miRNAs) can lead to an increased risk of cancer/leukemia development. Here, we focus on the study of a ubiquitous, multifunctional, and oncogenic miRNA-hsa-miR-155-5p (miR-155, MIR155HG), which is overexpressed in malignancies including chronic lymphocytic leukemia (CLL). Nonetheless, the precise mechanism of how miR-155 regulates the cell cycle in leukemic cells remains the subject of extensive research.

METHODS

We edited the CLL cell line MEC-1 by CRISPR/Cas9 to introduce a short deletion within the MIR155HG gene. To describe changes at the transcriptome and miRNome level in miR-155-deficient cells, we performed mRNA-seq/miRNA-seq and validated changes by qRT-PCR. Flow cytometry was used to measure cell cycle kinetics. A WST-1 assay, hemocytometer, and Annexin V/PI staining assessed cell viability and proliferation.

RESULTS

The limited but phenotypically robust miR-155 modification impaired cell proliferation, cell cycle, and cell ploidy. This was accompanied by overexpression of the negative cell cycle regulator p21/CDKN1A and Cyclin D1 (CCND1). We confirmed the overexpression of canonical miR-155 targets such as PU.1, FOS, SHIP-1, TP53INP1 and revealed new potential targets (FCRL5, ISG15, and MX1).

CONCLUSIONS

We demonstrate that miR-155 deficiency impairs cell proliferation, cell cycle, transcriptome, and miRNome via deregulation of the MIR155HG/TP53INP1/CDKN1A/CCND1 axis. Our CLL model is valuable for further studies to manipulate miRNA levels to revert highly aggressive leukemic cells to nearly benign or non-leukemic types.

miRNA Biology in Chronic Lymphocytic Leukemia

microRNAs (miRNAs) are a class of small non-coding RNAs that play a crucial regulatory role in fundamental biological processes and have been implicated in various diseases, including cancer. The first evidence of the cancer-related function of miRNAs was discovered in chronic lymphocytic leukemia (CLL) in the early 2000s. Alterations in miRNA expression have since been shown to strongly influence the clinical course, prognosis, and response to treatment in patients with CLL. Therefore, the identification of specific miRNA alterations not only enhances our understanding of the molecular mechanisms underlying CLL but also holds promise for the development of novel diagnostic and therapeutic strategies. This review aims to provide a comprehensive summary of the current knowledge and recent insights into miRNA dysregulation in CLL, emphasizing its pivotal roles in disease progression, including the development of the lethal Richter syndrome, and to provide an update on the latest translational research in this field.

Chronic lymphocytic leukaemia/small lymphocytic lymphoma and mantle cell lymphoma: from early lesions to transformation

The International Clinical Advisory Committee reviewed advances in our understanding of the clinicopathologic and biologic features of chronic lymphocytic leukaemia/small lymphocytic lymphoma, B-cell prolymphocytic leukaemia, and mantle cell lymphoma since the revised 4th edition of the WHO Classification of Tumours of the Haematopoietic and Lymphoid Tissues. Discussions amongst pathologists, clinicians, and molecular geneticists around these diseases focussed on incorporating new knowledge into the next classification system. In this manuscript, we review these disease entities and incorporate results of these deliberations, including advances in our understanding of early lesions and transformation.

Mantle Cell Lymphoma Presenting as Acute Abdominal Syndrome: A Rare Case Report and Literature Review

BACKGROUND

Acute abdominal syndrome can be caused by several possible reasons. The most common causes are perforation of a gastroduodenal ulcer, peritonitis, intestinal obstructions, and perforation of an appendix or fallopian tube. Fever and pain can be caused by an appendicitis or sigmoiditis. Appendiceal lymphoma is a rare disease that is usually found incidentally during appendectomy. Most of the cases are non-Hodgkin's lymphomas. Mantle cell lymphoma is an aggressive B-cell non-Hodgkin's lymphoma with a poorer prognosis than other B-cell lymphomas; thus, a definitive diagnosis is essential.

CASE SUMMARY

A 60-year-old man presented with right lower quadrant pain. He denied any nausea, vomiting or anorexia and was afebrile. The physical examination revealed right lower quadrant abdomen tenderness. The computed tomography scan revealed periappendiceal fatty stranding with a swollen appendix, approximately 2 cm in diameter and prominent paraaortic, portacaval and mesenteric lymph nodes. A diagnosis of acute appendicitis was made, and laparoscopic appendectomy was performed immediately. The subsequent pathological examination revealed severe congestion with lymphoid hyperplasia. The immunohistochemistry stains revealed positive staining for cluster of differentiation (CD) CD20, B-cell lymphoma-2 (Bcl-2), cyclin D1, SRY-box transcription factor-11 (SOX-11), immunoglobulin D (IgD) and immunoglobulin M (IgM) but negative staining for CD3, CD5, CD10 and CD23. 18F-FDG positron emission tomography showed peripheral lymph node involvement, while the bone marrow biopsy showed negative findings. Therefore, a diagnosis of mantle cell lymphoma, Ann Arbor stage IVA, was made. The patient received postoperative combination chemotherapy and remained in a stable condition over a 1-year follow-up period.

CONCLUSION

We report an uncommon case that initially presented as acute appendicitis, for which a final diagnosis of mantle cell lymphoma was made. In comparison with other B-cell lymphomas, mantle cell lymphoma has a poorer prognosis, and positive immunochemical staining of cyclin D1 and SOX-11 is useful for differentiating mantle cell lymphoma from other appendiceal lymphomas and treating patients appropriately. Physicians and nursing staff should be also aware of the associated complications and management in these patients.

The pathological features of leukemic cells infiltrating the renal interstitium in chronic lymphocytic leukemia/small lymphocytic lymphoma from a large single Chinese center

Background

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is rare in Asians, and patients with CLL/SLL seldomly undergo kidney biopsy. The histopathological features and clinical relevance of tubulointerstitial injury in CLL/SLL have not been extensively characterized. Hence, we attempted to describe the clinical characteristics, renal pathology and clinical outcome of a well-characterized population of CLL/SLL patients with CLL cell infiltration in the renal interstitium from a large single center in China.

Methods

Between January 1st, 2010 and September 31st, 2020, 31946renal biopsies were performed at Peking University First Hospital, and 10 CLL/SLL patients with CLL cell infiltration in the renal interstitium were included. Complete clinical data were collected from these 10 patients, and renal specimens were examined by routine light microscopy, immunofluorescence and electron microscopy.

Results

The extent of the infiltrating CLL cells in patients with CLL/SLL varied among different patients and ranged from 10 to 90% of kidney parenchyma. Six (60%) of 10 patients presented with an extent of infiltrating CLL cells ≥50%. Interestingly, we found that three patients (3/10, 30%) expressed monoclonal immunoglobulins in the infiltrating CLL cells, and special cytoplasmic crystalline structures were found in two of the three patients by electron microscopy for the first time. Severe renal insufficiency (Scr ≥200 μmol/L) was associated with ≥50% interstitial infiltration of CLL cells in the renal interstitium.

Conclusions

The current study confirmed that CLL cells infiltrating the renal interstitium can directly secrete monoclonal immunoglobulins, indicating that the interstitial infiltrating CLL cells possibly cause renal injury directly by secreting monoclonal immunoglobulins in situ. This finding may prove a new clue to elucidate the pathogenetic mechanism of renal injury involved with CLL/SLL.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13000-021-01120-4.

Utility of Cyclin D1 in the Diagnostic Workup of Hematopoietic Neoplasms: What Can Cyclin D1 Do for Us?

Cyclin D1, encoded by CCND1, promotes cell cycle progression from G1 to S phase. Its expression is induced by MAPK/ERK pathway as well as translocations/rearrangements involving CCND1 gene. The evaluation of cyclin D1 expression by immunohistochemistry plays an important role in the diagnostic workup of various hematopoietic diseases. In this review, we aimed to discuss the value of cyclin D1 immunostain in the diagnosis and different diagnosis of hematopoietic neoplasms.

PD-1 Expression in Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) and Large B-cell Richter Transformation (DLBCL-RT): A Characteristic Feature of DLBCL-RT and Potential Surrogate Marker for Clonal Relatedness

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is a low-grade B-cell neoplasm and ∼2% to 9% patients develop an aggressive lymphoma, most commonly diffuse large B-cell lymphoma (Richter transformation, DLBCL-RT). Programmed death-1 (PD-1) pathway plays a crucial role in tumor host immunity evasion and its blockade has emerged as an effective anti-cancer immunotherapy. PD-L1 and PD-1 expression has shown predictive value in anti-PD cancer immunotherapy; however, it has not been well documented in CLL/SLL and DLBCL-RT. We evaluated PD-1 and PD-L1 expression by immunohistochemistry in 39 CLL/SLL, 15 DLBCL-RT, and 26 other DLBCL. In CLL/SLL, neoplastic B-cell PD-1 expression was weak and restricted to prolymphocytes/paraimmunoblasts within proliferation centers (PCs) and accentuated PCs of all sizes. Neoplastic B-cell PD-1 expression was highly prevalent and demonstrated increased intensity in DLBCL-RT, but in contrast was only rarely seen in other DLBCL (12/15 vs. 1/26; P<0.0001). An excellent correlation (90% concordance) was observed between neoplastic B-cell PD-1 immunohistochemistry positivity and molecularly defined CLL/SLL clonal relatedness in DLBCL-RT. PD-L1 expression was observed on the neoplastic B cells in rare DLBCL-RT and other DLBCL cases (1/15 vs. 1/26; P>0.05) as well as background histiocytes and dendritic cells. Overall survival of DLBCL-RT was significantly inferior to that of the other DLBCL (median, 16.9 vs. 106.1 mo; P=0.002). Our findings suggest a biological continuum from prolymphocytes/paraimmunoblasts in CLL/SLL PCs to the neoplastic B-cells in DLBCL-RT. The characteristic PD-1 expression in DLBCL-RT makes it a potential surrogate marker for determining clonal relatedness to CLL/SLL, which may have important prognostic and therapeutic implications.

SOX11: friend or foe in tumor prevention and carcinogenesis?

Sex-determining region Y-related high-mobility-group box transcription factor 11 (SOX11) is an essential member of the SOX transcription factors and has been highlighted as an important regulator in embryogenesis. SOX11 studies have only recently shifted focus from its role in embryogenesis and development to its function in disease. In particular, the role of SOX11 in carcinogenesis has become of major interest in the field. SOX11 expression is elevated in a wide variety of tumors. In many cancers, dysfunctional expression of SOX11 has been correlated with increased cancer cell survival, inhibited cell differentiation, and tumor progression through the induction of metastasis and angiogenesis. Nevertheless, in a limited number of malignancies, SOX11 has also been identified to function as a tumor suppressor. Herein, we review the correlation between the expression of SOX11 and tumor behaviors. We also summarize the mechanisms underlying the regulation of SOX11 expression and activity in pathological conditions. In particular, we focus on the pathological processes of cancer targeted by SOX11 and discuss whether SOX11 is protective or detrimental during tumor progression. Moreover, SOX11 is highlighted as a clinical biomarker for the diagnosis and prognosis of various human cancer. The information reviewed here should assist in future experimental designs and emphasize the potential of SOX11 as a therapeutic target for cancer.

Chronic follicular pleuritis: a B cell-rich form of nonspecific pleuritis/fibrosis

The parietal pleura is often biopsied in patients with idiopathic pleural effusion, and in up to 40% of cases, a diagnosis of nonspecific pleuritis/fibrosis (NSP) is rendered. The histology of this reaction has not been well described including a pattern of B cell lymphoid hyperplasia described as "chronic follicular pleuritis (CFP)". Thirty-two cases of NSP were studied, of which 13 (41%) corresponded to CFP with the remainder displaying a fibrinous and organizing pleuritis with varying degrees of collagenization. CFP had similar etiologies as NSP with long term follow-up, including cardiac disease, pericarditis, asbestos exposure, and occult malignancy. The importance of recognizing a previously undescribed B cell/plasma cell pleural inflammatory response in reactive pleural disease is discussed.

Clinical Impact of the 2016 Update to the WHO Lymphoma Classification

OPINION STATEMENT

The 2016 revision of the WHO classification of lymphoid neoplasms includes new entities along with a clearer definition of provisional and definitive subtypes based on better understanding of the molecular drivers of lymphomas. These changes impact current treatment paradigms and provide a framework for future clinical trials. Additionally, this update recognizes several premalignant or predominantly indolent entities and underscores the importance of avoiding unnecessarily aggressive treatment in the latter subsets.

Chronic lymphocytic leukemia with proliferation centers in bone marrow is associated with younger age at initial presentation, complex karyotype, and TP53 disruption

The presence of expanded proliferation centers (PCs) in lymph nodes involved by chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma has been associated with adverse clinical outcomes, but the frequency and significance of PCs in bone marrow (BM) remain unclear. The study group included 36 patients with BM involvement by CLL in which PCs were present. We compared this group with 110 randomly selected BM samples involved by CLL without morphologically discernable PCs. Patients with PCs in BM were younger (median age, 53 years [range,18-71 years] versus 58 years [range, 31-82 years]; P = .007), more frequently experienced B symptoms (27.8% versus 8.2%, P = .0076), more often had Rai stage IV disease (30.6% versus 17.3%, P = .02) and higher serum lactate dehydrogenase (P = .0037) and β₂-microglobulin (P = .0001) levels, and lower hemoglobin (P = .026) and platelet counts (P = .0422). TP53 alterations were more common in patients with PCs in BM (45.4% versus 18.7%; P = .0049), as was a complex karyotype (26.4% versus 9%; P = .019). There were no significant differences in the frequency of ZAP70 or CD38 positivity or IGHV mutation status. The median time to first treatment was shorter in patients with PCs in BM (7 months versus 19 months, P = .047), and the frequency of Richter syndrome was higher (14% versus 4%, P = .041). Patients with PCs in BM had significantly shorter overall survival compared with the control group (median, 249.3 months versus undefined; P = .0241). These data suggest that identification of PCs in BM samples involved by CLL is associated with adverse prognostic features.

EZH2 is upregulated in the proliferation centers of CLL/SLL lymph nodes

Lymph node involvement of chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL) is characterised by the diffuse infiltration of small neoplastic lymphocytes, which is accompanied by the presence of proliferation centres (PCs) comprising prolymphocytes and paraimmunoblasts. There is increasing evidence of accumulation of various molecular alterations in the tumour cells of PCs, which may explain why extended PCs are related to a less favourable prognosis. To further characterize PCs, we compared the expression level of EZH2 protein, the overexpression of which has recently been recognized as poor prognostic factor in CLL/SLL, in the PCs and the intervening small cell areas in lymph nodes of 15 patients with CLL/SLL. We also investigated the mutational profile of EZH2 and the expression of its upstream regulators c-Myc, E2F1, pRB and miR-26a. Our results showed a significantly increased expression of EZH2 in the PCs. No EZH2 mutations were detected, however, overexpression of c-Myc, E2F1 and pRb proteins as well as reduced expression of the tumor suppressor miR-26a were demonstrated in the PCs. In summary our findings indicate that EZH2 pathway is significantly upregulated in the PCs of CLL/SLL lymph nodes, providing further evidence for the distinguished biological features of the PCs.

Cyclin D1 expression by histiocytes may mimic cyclin D1-positive proliferation centres of chronic lymphocytic leukaemia/small lymphocytic lymphoma

AIMS

Cyclin D1, generally considered to be absent in chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL), has been reported in the proliferation centres (PCs) of recent CLL/SLL cases. Cyclin D1 immunostaining in CLL/SLL may lead to diagnostic confusion. The objective of this study was to identify the types of stained cells and the impact on diagnosis.

METHODS

Cyclin D1 expression was assessed by immunostaining samples from 46 cases of CLL/SLL. CD68 and double immunostaining with CD20/CyclinD1, CD68/CyclinD1, and CD163/CyclinD1 were then performed in cases of CLL/SLL positive for cyclinD1 in the PCs.

RESULTS

Dim-positive cyclin D1 staining in randomly scattered cells in the CLL/SLLs were observed in 38/46 cases (82.6%). In five (10.9%) cases, more than 50 cyclin D1-positive cells per high-power field were detected within the PCs in CLL/SLL with weak to moderate intensity. Double immunochemical staining in these cases showed that cyclin D1 in these positive cells was mostly co-expressed with CD68 and CD163 and the cells were negative for CD20.

CONCLUSIONS

The cyclin D1-positive CLL/SLL cells in this study were mostly histiocytes. The expression of cyclin D1 by histiocytes may mimic cyclin D1+ CLL/SLL; thus, the recognition of cyclin D1 expression by non-lymphoid cells in lymphoma is important.

NFATC1 activation by DNA hypomethylation in chronic lymphocytic leukemia correlates with clinical staging and can be inhibited by ibrutinib

B cell receptor (BCR) signaling is a key for survival of chronic lymphocytic leukemia (CLL) cells, and BCR signaling inhibitors are clinically active. However, relapse and resistance to treatment require novel treatment options. To detect novel candidate therapeutic targets, we performed a genome-wide DNA methylation screen with custom arrays and identified aberrant promoter DNA methylation in 2,192 genes. The transcription factor NFATC1 that is a downstream effector of BCR signaling was among the top hypomethylated genes and was concomitantly transcriptionally upregulated in CLL. Intriguingly, NFATC1 promoter DNA hypomethylation levels were significantly variant in clinical trial cohorts from different disease progression stages and furthermore correlated with Binet disease staging and thymidine kinase levels, strongly suggesting a central role of NFATC1 in CLL development. Functionally, DNA hypomethylation at NFATC1 promoter inversely correlated with RNA levels of NFATC1 and dysregulation correlated with expression of target genes BCL-2, CCND1 and CCR7. The inhibition of the NFAT regulator calcineurin with tacrolimus and cyclosporin A and the BCR signaling inhibitor ibrutinib significantly reduced NFAT activity in leukemic cell lines, and NFAT inhibition resulted in increased apoptosis of primary CLL cells. In summary, our results indicate that the aberrant activation of NFATC1 by DNA hypomethylation and BCR signaling plays a major role in the pathomechanism of CLL.

Cytologic perspectives on neoteric B-cell lymphoproliferative disorders

The 2008 World Health Organization (WHO) classification of hematopoietic and lymphoid tissues has been recently revised, and publication of the updated 2016 version is expected soon. Given that cytopathologists are often involved in the diagnosis of primary, recurrent, and transformed lymphoproliferative disorders, knowledge of updates to the WHO lymphoma classification, including terminology, pathogenesis, ancillary techniques, and targeted therapies is necessary. Herein, we reference the last decade of cytology specific literature for seven newer B-cell disorders and provide illustrative examples of each entity from our files.

Genetic aberrations in small B-cell lymphomas and leukemias: molecular pathology, clinical relevance and therapeutic targets

Small B-cell lymphomas and leukemias (SBCLs) are a clinically, morphologically, immunophenotypically and genetically heterogeneous group of clonal lymphoid neoplasms, including entities such as chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), mantle cell lymphoma (MCL), follicular lymphoma (FL), lymphoplasmacytic lymphoma (LPL), marginal zone lymphoma (MZL) and hairy cell leukemia (HCL). The pathogenesis of some of these lymphoid malignancies is characterized by distinct translocations, for example t(11;14) in the majority of cases of MCL and t(14;18) in most cases of FL, whereas other entities are associated with a variety of recurrent but nonspecific numeric chromosomal abnormalities, as exemplified by del(13q14), del(11q22), and +12 in CLL, and yet others such as LPL and HCL that lack recurrent or specific cytogenetic aberrations. The recent surge in next generation sequencing (NGS) technology has shed more light on the genetic landscape of SBCLs through characterization of numerous driver mutations including SF3B1 and NOTCH1 in CLL, ATM and CCND1 in MCL, KMT2D and EPHA7 in FL, MYD88 (L265P) in LPL, KLF2 and NOTCH2 in splenic MZL (SMZL) and BRAF (V600E) in HCL. The identification of distinct genetic lesions not only provides greater insight into the molecular pathogenesis of these disorders but also identifies potential valuable biomarkers for prognostic stratification, as well as specific targets for directed therapy. This review discusses the well-established and recently identified molecular lesions underlying the pathogenesis of SBCLs, highlights their clinical relevance and summarizes novel targeted therapies.

The 2016 revision of the World Health Organization classification of lymphoid neoplasms

A revision of the nearly 8-year-old World Health Organization classification of the lymphoid neoplasms and the accompanying monograph is being published. It reflects a consensus among hematopathologists, geneticists, and clinicians regarding both updates to current entities as well as the addition of a limited number of new provisional entities. The revision clarifies the diagnosis and management of lesions at the very early stages of lymphomagenesis, refines the diagnostic criteria for some entities, details the expanding genetic/molecular landscape of numerous lymphoid neoplasms and their clinical correlates, and refers to investigations leading to more targeted therapeutic strategies. The major changes are reviewed with an emphasis on the most important advances in our understanding that impact our diagnostic approach, clinical expectations, and therapeutic strategies for the lymphoid neoplasms.

Diagnostic utility of SOX11 immunohistochemistry in differentiating cutaneous spread of mantle cell lymphoma from primary cutaneous B-cell lymphomas

BACKGROUND

Mantle cell lymphoma (MCL) is associated with the worst prognosis among low-grade B-cell lymphomas. While cutaneous involvement by nodal or systemic MCL is uncommon, its differentiation from primary cutaneous B-cell lymphoma (CBCL) or cutaneous involvement by other extra-cutaneous BCL is challenging as neither histomorphology nor immunophenotype can be absolutely specific. We analyzed the diagnostic utility of SOX11 immunohistochemistry in differentiating secondary cutaneous MCL from other low-grade CBCL.

METHODS

Immunohistochemical staining with anti-SOX11 antibody was performed on 8 cases of secondary cutaneous MCL, 16 secondary cutaneous CLL, 20 primary cutaneous MZL, 12 cutaneous FCL (6 primary, 6 secondary), 7 primary cutaneous DLBCL, leg type, 5 systemic DLBCL and 3 B-ALL. SOX11 and cyclin D1 staining were compared in secondary cutaneous MCL.

RESULTS

Nuclear SOX11 staining was seen in seven of eight cases (88%) of secondary cutaneous MCL, including a case with minimal cyclin D1 expression. All other CBCL lacked detectable nuclear SOX11 expression. The sensitivity and specificity for SOX11 in MCL were 87.5 and 100%, respectively. Both the sensitivity and specificity for combined SOX11 and cyclin D1 immunohistochemistry were 100%.

CONCLUSION

SOX11 immunohistochemistry could be a useful adjunct in distinguishing secondary cutaneous MCL from other CBCL.

New Immunohistochemistry for B-Cell Lymphoma and Hodgkin Lymphoma

Context

B-cell non-Hodgkin lymphoma is a heterogeneous group of lymphoproliferative malignancies with different clinical behaviors and treatments. It is important to differentiate individual B-cell lymphoma to apply the best treatment and management. Morphology and immunohistochemistry are the primary tools used for diagnosing lymphoma. There is a characteristic pattern of expression with immunohistochemical antibodies in most well-defined B-cell lymphomas. Some cases of B-cell lymphoma, however, show unusual morphologic and immunophenotypic features. The new and sometimes more specific antibodies have been developed recently, which may further define those lymphomas. Only with use of the antibodies over time does their true nature and specificity become evident.

Objectives

To present new antibodies for B-cell lymphoma that enhance the probability for diagnosis or can act as alternate markers in unusual cases, in which a B-cell lymphoma does not present with characteristic immunohistochemical staining, and to present prognostic markers that allow for better management of patients with specific B-cell lymphomas.

Data Sources

Data were obtained from literature review and figures from slides in personal practice.

Conclusions

The immunohistochemical antibodies presented in this article increase our ability to understand, diagnosis, and manage patients with B-cell lymphoma.

Atypical case of B-cell Chronic Lymphocytic Leukemia presenting with extreme hyperleukocytosis / Hiperleucocitoză extremă într-un caz atipic de leucemie limfatică cronică cu celulă B

Very few cases of chronic lymphocytic leukemia (CLL) presenting with extreme hyperleukocytosis are reported in the literature. We describe the case of a 66 years old woman, with newly diagnosed CLL presenting with extreme hyperleukocytosis of 774.2 x 109/liter, Rai stage III and Binet stage C. The patient has no comorbidities and the CIRS score (cumulative illness rating scale) is well below 6, with normal creatinine clearance. Some other interesting aspects related with this case are the atypical immunophenotype, the expression of Cyclin D1, and the B hepatitis viral infection, which made her diagnosis and treatment challenging. The patient was tested for NOTCH1 mutation and it was positive. There is important evidence that NOTCH1 mutations are associated with rapidly progressive disease and resistance to treatment. The distinction of CLL from mantle cell lymphoma (MCL) is not always easy because some MCLs may mimic CLL clinically, histologically, and/or phenotypically. The hepatitis B prophylaxis for viral reactivation was not available an in the end the patient was treated only with fludarabine and cyclophosphamide, without rituximab. CD200 should be introduced in the routine panel for flow cytometry to distinguish CLL from mantle cell lymphoma and NOTCH1 mutation is associated with poor prognosis and should be evaluated at diagnosis. CLL with extreme hyperleukocytosis presentation is very rare and sometimes an atypical CLL may represent a diagnostic pitfall.