Received: 25 September 2019 | Revised: 18 February 2020 | Accepted: 29 February 2020 DOI: 10.1002/ccr3.2813 CASE REPORT Bone marrow fibrosis, sequence variant of asxl1, and Sjögren syndrome: A case report Marta Santaliestra1 | Elena Bussaglia1 | Marta Pratcorona1 | Anna Monter-Rovira1 | Silvana Saavedra1 | Anna Mozos2 | Clara Martínez1 | Josep F. Nomdedéu1 1 Hematology Department, Hospital de la Santa Creu i Sant Pau, Universitat Abstract Autònoma de Barcelona, Barcelona, Spain Only proven pathogenic mutations associated with myeloid neoplasms are key to es- 2 Pathology Department, Hospital de tablish the clonal nature of the bone marrow fibrosis. In cases with genetic variants of la Santa Creu i Sant Pau, Universitat uncertain meaning, the clinical picture may be required to rule out secondary causes. Autònoma de Barcelona, Barcelona, Spain KEYWORDS Correspondence Josep F Nomdedéu, Hematology ASXL1, autoimmune, bone marrow fibrosis, molecular, Sjögren syndrome Department, Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain. Email: jnomdedeu@santpau.cat 1 | IN T RO D U C T ION myelofibrosis by the absence of splenomegaly and leuko- erythroblastic reaction.4-6 The distinction between primary myelofibrosis (PMF) and Primary myelofibrosis (PMF) is a myeloproliferative neo- autoimmune myelofibrosis (AIMF) can be a diagnostic chal- plasm (MPN) characterized by BM fibrosis, ineffective he- lenge because of the overlapping findings. We report a case matopoiesis, and a bad prognosis. In 90% of cases, we can of difficult differential diagnosis between PMF and AIMF identify a clonal mutation that confers a proliferative advan- in whom we simultaneously detected a variant sequence of tage, being the most common JAK2, MPL, and CALR. The ASXL1, which was interpreted as a clonal marker, and a di- remaining 10% of cases without any of these three clonal agnosis of Sjögren syndrome (SS) was established. markers harbor a wide range but uncommon activating mu- Bone marrow fibrosis (BMF) is a histopathological find- tations and are considered as being "triple-negative". One of ing presents in several diseases (malignant tumors, endo- these additional mutations detected in PMF involves the gene crine, and autoimmune disorders and infections).1,2 ASXL1 ("additional sex combs 1 like"), and it has been asso- Autoimmune myelofibrosis (AIMF) is an uncommon ciated with a bad outcome.7 The detection of a clonal marker cause of nonmalignant BMF, it can occur in the presence is one of the criteria for the diagnosis of the PMF (WHO of a systemic autoimmune disease, or it can be the primary 2008 and 2016). finding in the absence of a clinically diagnosed autoimmune Differential diagnosis between PMF and nonneoplastic disease if serologic evidence of autoantibodies is detected.3 BMF (as AIMF) can be a diagnostic challenge, because of the AIMF is characterized by cytopenias and autoantibodies with overlapping pathologic findings in the two entities and the nonclonal BM fibrosis, and it is distinguished from primary important differences in prognostic and therapeutic options. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2020 The Authors. Clinical Case Reports published by John Wiley & Sons Ltd. Clin Case Rep. 2020;8:1269–1273.  wileyonlinelibrary.com/journal/ccr3 | 1269 1270 |    SANTALIESTRA et al. 2 | C LIN ICA L CA SE referred to the rheumatology unit and was diagnosed with SS without specific treatment requirements. A 48-year-old woman with a history of hypertension and Despite presenting an autoimmune disease, which could two cesarean deliveries presented to the emergency room in be a cause of BMF, we classified the patient as having a PMF October 2013 with a marked anemic syndrome. The blood in accordance with the 2016 WHO classification, due to the tests showed hemoglobin (Hb) of 4 g/dL with normal platelet presence of a high-risk clonal marker (ASXL1). A donor and leukocyte counts, without signs of hemolysis. It was ori- search for hematopoietic stem cell transplantation (HSCT) ented as iron deficiency anemia, and two red blood cell units was started. were transfused. The clinical evolution was not typical of PMF: she had She remained clinically stable during a year, with Hb episodes of severe anemia needing a transfusion but respon- >10 g/dL, until November 2014, when she came again to the sive corticosteroid therapy; she did not have splenomegaly Hospital with an anemic syndrome. The blood test showed nor leucoerythroblastic reaction. Erythropoietin was also ad- Hb 7.6 g/dL with reticulocytopenia and without signs of he- ministered without clinical benefits. We decided to perform a molysis. No teardrop cells were observed in the peripheral new bone marrow study to reassess the disease. A bone mar- blood. To study this nonregenerative anemia, a bone marrow row biopsy was performed after corticosteroid treatment, and study was requested. No material was obtained in the bone it showed polymorphic hematopoiesis with normal mega- marrow aspiration, and the bone marrow biopsy was sugges- karyocytes and the absence of BMF (Figure 3). Because of a tive of MPN (increased hematopoietic cellularity with tissue reversible BMF in the context of an autoimmune disease, she displacement, presence of dysmorphic megakaryocytes, and was diagnosed with AIMF. extense reticulin fibrosis, grade 3) (Figure 1). BCR-ABL1, We repeated the molecular study in a peripheral blood JAK2, CALR, and MPL were negative, and no cytogenetic sample, detecting the same mutation in ASXL1 (exon 12: study was performed. It did not meet all the criteria for the c2400T > G/p.D800E; VAF 53.5%). This sequence variation diagnosis of PMF according to the WHO 2008 classification. has not been described as polymorphism, and its pathogenic The patient was asymptomatic at follow-up with chronic ane- effect, if any, is currently unknown. The presence of a mu- mia but without transfusion requirements (Hb > 10 g/dL). tation of an uncertain significance, even in a heterozygote One year later, in November 2015, she had a new episode state without changes in the VAF, suggested us to hold the of anemia of the same characteristics without leucoeryth- follow-up in the hematology department. The patient is cur- roblastic reaction nor splenomegaly. A new bone marrow rently free of symptoms. study was done with similar findings to the previous biopsy (Figure 2). Cytogenetics: 46, XX. Molecular: SETBP1 and CSF3R were negative, and a mutation was detected in exon12 3 | DISCUSSION of ASXL1c2400T > G/p.D800E (VAF 55.4%). During the follow-up, the patient showed salivary gland Bone marrow fibrosis is an uncommon finding associated adenitis, a dry eye with Raynaud's syndrome, so she was with different clinical disorders. The histologic traits include F I G U R E 1 First bone marrow biopsy (November 2014): increased hematopoietic cellularity with tissue displacement, presence of dysmorphic megakaryocytes, and extensive reticulin fibrosis, grade 3 SANTALIESTRA et al.    | 1271 F I G U R E 2 Second bone marrow biopsy (November 2015) F I G U R E 3 Bone marrow study after corticosteroid therapy (September 2018): polymorphic hematopoiesis, normal megakaryocytes, and no bone marrow fibrosis F I G U R E 4 Evolution of blood counts after the start of corticosteroids (day 1:3/18/18) excessive deposits of extracellular matrix proteins (reticulin), reversed if the neoplastic cells are eradicated (as in the setting with hypercellularity, neoangiogenesis, and fibroblast pro- of HSCT). Marrow fibrosis could also occur in nonhemato- liferation. In primary hematologic disorders, fibrosis is due logic disorders such as chronic infectious diseases in which to the dysregulation of cytokines which arise in association the infection-mediated chronic inflammation may lead to en- with a malignant clone so the fibrosis could sometimes be hanced production of cytokines. The pathogenesis of AIMF 1272 |    SANTALIESTRA et al. is not well understood but the immune cells appear to drive and compromise its function, playing a role in leuke- the process of fibrosis.1-2,8 mogenesis. 12-14 Our patient presents a mutation in the AIMF is an infrequent cause of nonmalignant BMF, it can exon 12 of ASXL1 (c2400T > G/p.D800E). This change occur in the presence of systemic autoimmune disease, or it has been reported 3 times in the COSMIC database (one can be primary. There are certain criteria for establishing the pancreas, one bone, and one hematopoietic sample). diagnosis (all must be met): (a) grade 3-4 reticulin fibrosis, FATHMM prediction categorizes this change as neutral (b) absence of grouped or atypical megakaryocytes, (c) ab- (nonpathogenic) with a 0.15 score. Furthermore, T to sence of erythroid dysplasia, basophilia, or eosinophilia, (d) G changes are the less common ASXL1 mutations (2% mature lymphocytes in the bone marrow, (e) absence of os- of the reported cases). Bearing all this information in teosclerosis, (f) absence or mild splenomegaly, (g) serologic mind and with a stable VAF around 50% on two occa- evidence of autoantibodies, and (h) absence of other causes sions, we think that this ASXL1 change is nonpatho- of BMF.3 genic. Provided that ASXL1 mutations are considered BMF of unknown etiology was classified as PMF, but clonal markers in PMF, we suggest that its pathogenicity since 2008 WHO classification, there are some specific cri- should be tested using available databases before estab- teria for its diagnosis. These criteria were modified in the lishing a PMF diagnosis. 2016 WHO classification.9,10 For its diagnosis, 3 major and 1 minor criteria must be met. Major criteria are the follow- ing: (a) megakaryocyte proliferation and atypia (small-to- 4 | CONCLUSIONS large megakaryocytes with aberrant nuclear/cytoplasmatic ratio and hyperchromatic and irregularly folded nuclei and At presentation, we did not consider AIMF diagnosis given dense clustering), (b) not meeting WHO criteria for BCR- the absence of known autoimmune disease. The changes in ABL1 chronic myeloid leukemia (CML), polycythemia 2016 WHO classification (where only one minor criterion— vera (PV), essential thrombocythemia (ET), myelodysplas- anemia—was needed for the PMF diagnosis) suggested that tic syndrome (MDS), or other myeloid neoplasm, (c) pres- a PMF diagnosis could be established despite the atypical ence of JAK2, CALR, MPL mutation or, in the absence clinical evolution (absence of systemic symptoms, spleno- of any of these mutations, the presence of another clonal megaly…), absence of other cytopenias, raised LDH or leu- marker (the search for the most frequent accompanying coerythroblastic reaction. The finding of a bona fide clonal mutations—ASXL1, EZH2, TET2, IDH1/IDH2, SRSF2, mutation (ASXL1) can be very helpful in controversial cases, SF3B1—are thus very helpful in determining the clonal where the morphological findings and clinical presentation nature of the disease) or absence of evidence for reactive are ambiguous, but ASXL1 changes of uncertain meaning BMF. Minor criteria are the presence of one or more of the can also be a misleading factor (as it was in our case). We following confirmed in two consecutive determinations: must distinguish between PMF, with a compatible bone mar- anemia (not attributed to a comorbid condition), leuko- row study and a clonal marker, but atypical clinical evolu- cytosis ≥11 × 109/L, palpable splenomegaly, LDH level tion, and AIMF, with typical evolution but the presence of an above the upper limit of the institutional reference range ASXL1 sequence variant. In this scenario, it is very impor- (Figure 4), and/or leukoerythroblastosis. tant to consider the whole clinical picture in context; in the Distinguishing between PMF and nonneoplastic BMF (as case under discussion, the bone marrow study after corticos- AIMF) can be a practical diagnostic challenge, because of teroid therapy confirmed the diagnosis. the overlapping findings in the two entities and the important differences in terms of prognostic and therapeutic options. CONFLICT OF INTEREST PMF is a BCR-ABL1-negative MPN associated with a poor None declared. prognosis, and HSCT is the only curative option. AIMF has a favorable prognosis, and it is reversible with a short course AUTHOR CONTRIBUTIONS of corticosteroids. MS: has made substantial contributions to conception and Loss-of-function mutations and deletions in ASXL1 design, and analysis and interpretation of data, and wrote are observed in patients with myeloid malignancies the manuscript; EB: performed molecular analysis; MP: per- (more frequently in myelodysplastic syndromes) and are formed molecular analysis; AM-R: obtained morphologic and associated with poor outcomes. 11 The ASXL1 gene is molecular data; SS: served as clinician and patient-reported located in the chromosomal region 20q11, and the mu- in charge; AM: involved in pathology data; EB, MP, AM-R, tations related to myeloid neoplasms are mostly hetero- SS, and AM: contributed to comments and suggestions; CM: zygous, frameshifts, and located in exon 12, affecting involved in morphologic assessment; JFN: involved in design the C-terminal plant homeodomain (PHD domain). The and interpretation of data. 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