A clinical, histopathological, and molecular study of two cases of VEXAS syndrome without a definitive myeloid neoplasm

VEXAS (vacuoles, E1 enzyme, X- linked, autoinflammatory, somatic) syndrome is caused by somatic mutations in UBA1 and is identified using a genotype-driven method. This condition connects unrelated men with adult-onset inflammatory syndromes in association with hematologic manifestations of peripheral cytopenia and bone marrow myeloid dysplasia. While bone marrow vacuolization restricted to myeloid and erythroid precursors has been identified in VEXAS patients, the detailed clinical and histopathological features of peripheral blood and bone marrows remain unclear. The current case report describes the characteristic hematologic findings in patients with VEXAS, including macrocytic anemia, thrombocytopenia, marked hypercellular marrow with granulocytic hyperplasia, megaloblastic changes in erythroid precursors, and the absence of hematogones in addition to prominent vacuoles in myeloid and erythroid precursor cells. Characterizing the clinical and hematologic features helps to raise awareness and improve diagnosis of this novel, rare, but potentially under-recognized disease. Prompt diagnosis expands the general knowledgeable and understanding of this disease, and optimal management might prevent patients from developing complications related to this refractory inflammatory syndrome and improve the overall clinical outcome.

Colony-stimulating factor 3 receptor gene (CSF3R) T618I mutated chronic myelomonocytic leukemia: A proliferative subtype with a distinct mutational profile

Introduction/Objective Chronic myelomonocytic leukemia (CMML) is a myeloid neoplasm characterized by sustained monocytosis, ranging from cytopenia with a dysplastic subtype to leukocytosis with a proliferative subtype, with a typical mutational profile involving TET2, ASXL1, and SRSF2. Mutation in colony-stimulating factor 3 receptor gene (CSF3R) is commonly associated with chronic neutrophilic leukemia (CNL) but exceedingly rare in CMML, particularly CSF3R T618I (~10 cases described, ~30 cases of CSF3R non-T618I mutations). We report a case of CSF3R T618I mutated CMML and compare the clinicopathologic features to reported CMML cases with and without CSF3R T618I mutations. Methods/Case Report A 27-year-old woman presented for evaluation of leukocytosis, sustained monocytosis, and anemia. Peripheral blood (PB) revealed leukocytosis (white cell count 35x109/L), left-shifted and dysplastic neutrophils (myelocytes and metamyelocytes, 5%), absolute and relative monocytosis (7x109/L, 29%), anemia (Hgb 4.3 g/dL), and thrombocytopenia. Bone marrow aspirate and core biopsy demonstrated a hypercellular marrow with increased myeloblasts (~3%, immunophenotypically aberrant by flow cytometry), increased myelomonocytic cells, and multilineage dysplasia, including ring sideroblasts and hypolobated megakaryocytes. Cytogenetic and molecular studies revealed a normal karyotype and mutations in CSF3R T618I, ASXL1, SETBP1, BCORL1, KRAS, and PTPN11. Despite the presence of a CSF3R T618I mutation, CMML was diagnosed given marked monocytosis, left- shifted neutrophils in PB, multilineage dysplasia, and immunophenotypically aberrant myeloblasts. Results (if a Case Study enter NA) NA Conclusion Our case demonstrates clinicopathological features similar to those of reported CSF3R T618I mutated CMML, i.e., a proliferative subtype and less likely to have co-occurring mutations in TET2 or SRSF2, which is distinct from CSF3R non-T618I mutated CMML; the latter often has a dysplastic subtype and mutational profile of frequent TET2 and SRSF2 mutations, similar to CSF3R unmutated CMML. While additional cases with this unusual mutation need to be studied to arrive at a more definitive conclusion, the CSF3R T618I mutation seems to define a unique proliferative subtype CMML with a distinct mutational profile.

CSF3R T618I, SETBP1 G870S, SRSF2 P95H, and ASXL1 Q780* tetramutation co-contribute to myeloblast transformation in a chronic neutrophilic leukemia

Chronic neutrophilic leukemia (CNL) is a rare but serious myeloid malignancy. In a review of reported cases for WHO-defined CNL, CSF3R mutation is found in about 90% cases and confirmed as the molecular basis of CNL. Concurrent mutations are observed in CSF3R-mutated CNL patients, including ASXL1, SETBP1, SRSF2, JAK2, CALR, TET2, NRAS, U2AF1, and CBL. Both ASXL1 and SETBP1 mutations in CNL have been associated with a poor prognosis, whereas, SRSF2 mutation was undetermined. Our patient was a 77-year-old man and had no significant past medical history and symptoms with leukocytosis. Bone marrow (BM) aspirate and biopsy revealed a markedly hypercellular marrow with prominent left-shifted granulopoiesis. Next-generation sequencing (NGS) of DNA from the BM aspirate of a panel of 28 genes, known to be pathogenic in MDS/MPN, detected mutations in CSF3R, SETBP1, and SRSF2, and a diagnosis of CNL was made. The patient did not use a JAK-STAT pathway inhibitor (ruxolitinib) but started on hydroxyurea and alpha-interferon and developed pruritus after 4 months of diagnosis and nasal hemorrhage 1 month later. Then, the patient was diagnosed with CNL with AML transformation and developed intracranial hemorrhage and died. We repeated NGS and found that three additional mutations were detected: ASXL1, PRKDC, MYOM2; variant allele frequency (VAF) of the prior mutations in CSF3R, SETBP1, and SRSF2 increased. The concurrence of CSF3RT618I, ASXL1, SETBP1, and SRSF2 mutation may be a mutationally detrimental combination and contribute to disease progression and AML transformation, as well as the nonspecific treatment of hydroxyurea and alpha-interferon, but the significance and role of PRKDC and MYOM2 mutations were not undetermined.

Clinico-haematological profile of adult pancytopenia patients at a tertiary care institute in South India

Background: Pancytopenia is not a disease by itself; rather it describes simultaneous presence of anemia, leukopenia and thrombocytopenia resulting from a number of disease processes. Varieties of hematological and non-hematological disorders may affect bone marrow either primarily or secondarily, resulting in the manifestation of pancytopenia. The incidence of various hematological disorders causing pancytopenia varies due to geographical distribution and genetic predisposition. This study highlights the spectrum of causes, clinical presentation and bone marrow morphology of pancytopenia.Methods: This prospective observational study was conducted for a period of two years at Al-Ameen Medical College, Bijapur, Bangalore. During this period, fifty patients with a hematological diagnosis of pancytopenia were studied during period in the department of pathology.Results: Among the 50 cases studied, 35 were males and 15 were females. Most of the patients presented with generalized weakness and fever. The commonest physical finding was pallor, followed by splenomegaly and hepatomegaly. Dimorphic anemia was predominant blood picture. Bone marrow study showed 72% hypercellular marrow, 12% normocellular and 16% hypocellular marrow. The commonest cause for pancytopenia was megaloblastic anemia followed by iron deficiency anaemia and malaria.Conclusions: The present study concludes that detailed hematological investigations along with bone marrow examination in pancytopenic patients is helpful to diagnose or rule out the causes of pancytopenia.

LSD1 Inhibition with IMG7289 (bomedemstat) Rebalances Megakaryopoiesis and Erythropoiesis in a Patient with MPN/MDS with Refractory Anemia with Ringed Sideroblast and Marked Thrombocytosis with JAK2 and SF3B1 Mutations

Lysine-specific demethylase-1 (LSD1) is a histone H3 K4 demethylase that plays a critical role in hematopoietic progenitor cell differentiation, in particular, the production of megakaryocytes and erythrocytes from their common classical bi-potent progenitor (MEP). LSD1 is recruited to chromatin by the transcription factor GFI1B to license the maturation of megakaryocyte-erythrocyte progenitor cells (MEPs). Anemia is a common and serious complication of primary myelofibrosis (PMF), which is often refractory to conventional therapy. We report here the effect of IMG-7289 (bomedemstat), an LSD1 inhibitor, on skewing the fate of MEPs favoring the production of red cells over platelets and producing a complete hematologic remission in a JAK2V617F-positive PMF patient who had developed a refractory anemia with ringed sideroblasts. A 63 year old woman presented in 2016 with a 1 year history of with fatigue significantly compromising her lifestyle. She denied fever, night sweats, or weight loss. The physical examination was unremarkable with no palpable splenomegaly. Laboratory studies showed a hemoglobin (Hb) of 11.3 g/dL, a total white blood cell count (WBC) of 20.3k/µL with leukoerythroblastosis with 1% circulating blast cells, and a platelet count of 1,192k/µL. A bone marrow biopsy (BMB) showed a hypercellular marrow with increased dysmorphic megakaryocytes but without dyserythropoiesis. There were no ringed sideroblasts with Perls stain, and silver staining showed grade 2 reticulin fibrosis. The karyotype was del(7)(q11.2) and genotyping identified a JAK2V716F allele (VAF not known). The patient was considered to have PMF. Initial treatment consisted of hydroxyurea but without any improvement in her symptoms. Financial constraints initially prevented access to ruxolitinib but the patient was eventually started on 15 mg BID in January 2018. She tolerated therapy well but discontinued therapy a year later owing to no improvement in her fatigue and opted for observation alone. Over the next year, her hemoglobin fell to the range of 9.0-9.5g/dl and she developed drenching night sweats. A BMB in August 2019 showed a hypercellular marrow with increased dysplastic megakaryocytes but now with 76% ringed sideroblasts. Reticulin stain showed grade 2-3 fibrosis. No other dysplastic features were observed. Additional genotyping was declined by insurance and the patient was considered to have an MPN/MDS overlap syndrome. Accordingly, the patient was enrolled in clinical trial IMG-7289-CTP-102 (NCT03136185), a study of the LSD1 IMG-7289. On entry, her Hb was 9.5 gm/dL with an absolute reticulocyte count of 129K/µL. The WBC was 22.7k/µL with 69% neutrophils and 11% monocytes. The platelet count was 1,585k/µL with a mean platelet volume (MPV) of 8.1 fL. Genotyping showed a JAK2V617F VAF of 27%, a new SF3B1K700E mutation with a VAF of 26%, and a DNMT3A mutation with a VAF of 95%. Spleen volume by imaging was 283.3 cm³. The starting IMG-7289 dose was 40 mg po QD. At week 12, the Hb rose to 13.8 g/dL while the absolute reticulocyte count fell to 40K/µL. The platelet count was 271k/µL with the MPV increasing to 10.5 fL. The WBC was 5.2k/µL with 58% neutrophils and 18% monocytes. The mutant JAK2 allele burden had dropped to 14%. The spleen volume was 223 cm³. The IMG-7289 dose was reduced to 35 mg QD after complaints of fatigue. At Week 24, Hb was 11.7 g/dL, WBC was 12.1k/µL and platelets were 743k/µL. The total symptom score (MPN SAF TSS) was reduced by 31% from baseline. The expected pharmacodynamic effects of LSD1 inhibition on hematopoiesis were evident in this patient: monocytosis with a decrease in neutrophils and a marked reduction in the platelet count. Most striking was the concurrent improvement in the patient's anemia which was associated with a persistent reticulocytosis present at the start of treatment but with a significant increase in red blood cells in the setting of a SF3B1 mutation. MEP fate decisions hinge on the balance between KLF1 and FLI1 with the former favoring an erythroid fate, the later, megakaryocytes. The transcription factor complex of FLI1, GATA1, FOG1 which recruits the LSD1-containing NuRD complex is essential for megakaryocyte function; IMG-7289 likely disrupts that complex favoring erythropoiesis over megakaryopoiesis. The inhibition of LSD1 may, therefore, in the setting of thrombocytosis and anemia, rebalance the fate of MEPs to ameliorate both abnormalities. Disclosures Yacoub: Novartis: Speakers Bureau; Agios: Honoraria, Speakers Bureau; Incyte: Speakers Bureau; Hylapharm: Current equity holder in private company; Cara Therapeutics: Current equity holder in publicly-traded company; Ardelyx: Current equity holder in publicly-traded company; Dynavax: Current equity holder in publicly-traded company; Roche: Other: Support of parent study and funding of editorial support. Rienhoff:Imago BioSciences: Current Employment, Current equity holder in private company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties.

Atypical Phenotype and Treatment Response Pattern in a Patient with FIP1L1-PDGFRα Mutation

Myeloproliferative disorders with eosinophilia may possess the FIP1L1-PDGFRα gene rearrangement. When this rearrangement is present, imatinib usually results in complete remission. In rare cases of imatinib resistance, there is poor evidence guiding second-line therapy. We present the case of a 71-year-old male who presented with abdominal discomfort, fevers, and leukocytosis with eosinophilia. The patient was diagnosed with a myeloproliferative neoplasm with eosinophilia and FIP1L1-PDGFRα rearrangement after a bone marrow evaluation revealed hypercellular marrow with eosinophilia and fluorescence in situ hybridization identified the FIP1L1-PDGFRα rearrangement. The patient was successfully treated with imatinib. Within months he relapsed and converted into acute myeloid leukemia. The patient was then treated with ponatinib which induced and maintained clinical and hematological remission for 2 months. That ponatinib briefly induced remission in our patient with acute myeloid leukemia arising from a myeloproliferative neoplasm with eosinophilia and FIP1L1-PDGFRα fusion may merit exploration of ponatinib as a potential second-line treatment option for this patient population. This is especially true given the lack of reliable therapies in instances of imatinib resistance.

Bone Marrow Examination in Cases of New-onset Pancytopenia: A Four-year Study from a Medical College in the Rural Hilly Setting of Western Himalayas, India

New-onset pancytopenia is a common diagnostic challenge. Pancytopenia is an indication for bone marrow examination. The present study has been carried out to determine the frequencies of various etiologies of pancytopenia based on bone marrow morphology in a defined geographical location. All cases of new-onset pancytopenia, diagnosed on peripheral smear and seen over a four-year period from January 2012 to December 2015 in the department of pathology, were analysed. Patients lacking representative bone marrow in the aspirate or receiving chemotherapy were excluded. Out of 69 cases, 29 were males and 40 were females. Most of the patients were in the age group of 19-60 years (52.2%). Nineteen (26.1%) of them were less than 18 years old. The three major causes of pancytopenia were: megaloblastic anemia (hypercellular marrow with megaloblastic erythropoiesis) in 25 (36.2%) cases, hypercellular marrow with dimorphic erythropoiesis in 13 (18.8%) cases, and haematological malignancies in 12 (17.4%) cases of the study. Bone marrow examination along with laboratory evaluation helps to establish specific diagnosis in cases of new-onset pancytopenia.

Primary Myelofibrosis Presenting as Extramedullary Hematopoiesis in a Transplanted Liver Graft: Case Report and Review of the Literature

Primary myelofibrosis (PMF) commonly results in extramedullary hematopoiesis (EMH) in the spleen and liver as well as a variety of other organs. We present a first report of a unique presentation of PMF in a liver transplant recipient patient as EMH in the transplanted liver graft. A 76-year-old man with history of cryptogenic cirrhosis received cadaveric liver transplantation in 1996. He maintained a normal graft function and stable hematologic parameters until 2013 when he presented with anemia and progressive fatigue. Extensive work-up did not identify the etiology of the recent decline in his hemoglobin; thus a liver biopsy was done which showed findings of EMH within the sinusoids with increased megakaryocytes, some with atypical morphology. A BM biopsy revealed a hypercellular marrow, moderately increased reticulin fibrosis, and features consistent with primary myelofibrosis. Abdominal imaging showed a normal-size spleen and did not identify any sites of EMH outside of the liver. The diagnosis of myelofibrosis was thus made, and this case demonstrated predominant tropism to a transplanted liver graft with absence of EMH elsewhere. We would thus like to emphasize that findings of EMH in subjects with no preexisting hematologic neoplasm should warrant close follow-up and assessment.

A 26-Year-Old Female with Systemic Mastocytosis with Associated Myeloid Neoplasm with Eosinophilia and Abnormalities ofPDGFRB, t(4;5)(q21;q33)

Various translocations involving thePDGFRBgene are identified in myeloid neoplasms. However, thePRKG2/PDGFRBfusion gene associated with t(4;5)(q21;q33) has previously been reported in only 3 patients. We present the case of a 26-year-old woman with microcytic anemia, basophilia, thrombocytosis, and massive splenomegaly, who was found to have systemic mastocytosis and associated clonal hematological non-mast cell lineage disease (SM-AHNMD), with myeloid neoplasm withPRKG2/PDGFRBrearrangement. Initial findings included basophilia (37%, 4.1 k/μL), hypercellular marrow with eosinophilia, and increased and atypical megakaryocytes, suggestive of myeloproliferative neoplasm. Additional studies revealed large clusters of CD25 positive mast cells, fulfilling the criteria for the diagnosis of systemic mastocytosis. Consistent with prior reports of this translocation, our patient has responded well to imatinib. This case, in conjunction with others in the literature, suggests a possible connection between t(4;5)(q21;q33)PRKG2/PDGFRBand systemic mastocytosis and highlights their favorable response to imatinib.

MDS with Isolated Trisomy 8. a Type of MDS Frequently Associated with Myeloproliferative Features? A Report from the GFM

Introduction Isolated trisomy 8 is a frequent cytogenetic abnormality in MDS, but hematological characteristics of MDS with isolated trisomy 8 have not been reported in detail. Patients and Methods This was a retrospective analysis of cases of MDS with isolated trisomy 8 diagnosed in 6 French centers of the Groupe Francophone des Myélodysplasies (GFM) between 2003 and 2013. Only patients with isolated trisomy 8 diagnosed as MDS or MPN/MDS (other than CMML) according to WHO were eligible, excluding AML, well characterized MPN (PV, ET) and CMML. Myeloproliferative (MP) features were defined by repeated presence (in the absence of infection) of one of the following: WBC > 10G/L, circulating immature granulocytes (myelemia ) > 2%, or palpable splenomegaly. Results 103 patients with isolated trisomy 8 were identified, with a median age of 75 years, and M/F 1.7. At diagnosis, median WBC count was 4.1 G/L, with WBC ≥ 10 G/L in 13 patients (12.6 %), myelemia ≥ 2% in 27 patients (26.2 %), palpable splenomegaly in 9 patients (8.7 %). WHO diagnosis included 20 RA, 2 RARS, 22 RCMD, 1 RCMD-RS, 1 RCUD, 21 RAEB-1, 18 RAEB-2, 7 MDS-U, 10 MDS/MPN, 1 hypoplastic MDS. IPSS was intermediate 1 (72.2 %), intermediate 2 (19.6 %), high (8.2 %) ; IPSS-R was low (37.1 %), intermediate (29.9 %), high (22.7 %), very high (10.6 %). MP features were found in 50 patients (48.5 %): 31 at diagnosis, 19 during evolution (in patients without MP features at diagnosis). Bone marrow morphological features could be reviewed in 15 MP cases, showing hypercellular marrow in 60 % cases, granulocytic hyperplasia (E/G<0.25) in 53%, marked neutrophil hypogranularity in 87% and abnormal chromatin clumping in neutrophils in 53 %. Somatic mutations were studied in 31 patients on diagnostic samples (16 MP and 15 non MP) for 27 most frequently mutated genes in MDS and MPN: ASXL1, CBL, DNMT3A, ETV6, EZH2, IDH1, IDH2, JAK2, cKIT, KRAS, NRAS, MPL, PHF6, PTPN11, RIT, RUNX1, SETBP1, SF3B1, SRSF2, TET2, TP53, U2AF1, WT1, ZRSR2, FLT3-TKD, FLT3-ITD, NPM1 (FLT3-TKD, FLT3-ITD and NPM1 were studied in only 15 patients). Mutations were seen, for MP cases, in ASXL1 (64%), EZH2 (50%), TET2 (40%), RUNX1 (33%), SRSF2 (27%), DNMT3A (15%), JAK2 (14%), IDH2 (14%), NRAS (8%), SF3B1 (9%), U2AF1 (8%); for non MP cases in ASXL1 (33%), SRSF2 (27%), SF3B1 (27%), TET2 (20%), DNMT3A (13%), JAK2 (13%), RUNX1 (13%), EZH2 (7%), IDH2 (7%), ZRSR2 (7%), NRAS (0%). In spite of a trend for more mutations of ASXL1 (p=0.128), and EZH2 (p=0.053) in MP forms, the difference with non MP forms was not significant, possibly due to small patient numbers. 40 patients received an HMA (AZA in 36, DAC in 4) and 27.3% responded (4 CR, 1 PR, 1 marrow CR, 3 HI), including 11.7% of MP cases and 43.8% of non MP cases (p=0.057). 5 patients received intensive chemotherapy (with 2 CR). 42 (40.8%) received an ESA, with 60% responses, including 50% in MP and 73% in non MP patients (p= NS).10 (9.7%) received hydroxyurea. With a median follow up of 30 months, progression to AML was seen in 26% and 18.9% in MP and non MP patients, respectively (p= NS). Median survival was 35 months in the whole cohort, without difference between patients who, at diagnosis had MP features and no MP features (35 months for both). Conclusion Myeloproliferative (MP) features were found at diagnosis or during evolution in our experience in about 50% of MDS with isolated trisomy 8, a finding not previously reported, to our knowledge, and suggesting that some of those patients may have to be reclassified among MDS/MPN. The subset of patients with MP features tended to have a higher frequency of ASXL1 and EZH2 mutations (findings that will have to be confirmed on larger patient numbers), and seemed to respond poorly to HMA, although its survival was not lower than that of non MP forms in our experience. Disclosures Park: Novartis: Membership on an entity's Board of Directors or advisory committees, Research Funding; Hospira: Research Funding; Celgene: Research Funding. Fenaux:AMGEN: Honoraria, Research Funding; CELGENE: Honoraria, Research Funding; JANSSEN: Honoraria, Research Funding; NOVARTIS: Honoraria, Research Funding.