Predictors of clinical outcome in myeloproliferative neoplasm, unclassifiable: A Bone Marrow Pathology Group study

OBJECTIVES

Myeloproliferative neoplasm, unclassifiable (MPN-U, revised to MPN, not otherwise specified in the fifth edition of the World Health Organization classification) is a heterogeneous category of primary marrow disorders with clinical, morphologic, and/or molecular features that preclude classification as a more specific MPN subtype due to stage at diagnosis, overlapping features between MPN subtypes, or the presence of coexisting disorders. Compared with other MPN subtypes, the contribution of the mutational landscape in MPN-U in conjunction with other clinical and morphologic biomarkers to prognosis has been less well investigated.

METHODS

We performed a multicenter, retrospective study of MPN-U (94 cases) to better define the clinicopathologic features, genetic landscape, and clinical outcomes, including subgroups of early-stage, advanced-stage, and coexisting disorders. The Dynamic International Prognostic Scoring System (DIPSS) plus scoring system was applied to assess its relevance to MPN-U prognosis.

RESULTS

Multivariate analysis demonstrated bone marrow blast count and DIPSS plus score as statistically significant in predicting overall survival. Univariate analysis identified additional potential poor prognostic markers, including abnormal karyotype and absence of JAK2 mutation. Secondary mutations were frequent in the subset analyzed by next-generation sequencing (26/37 cases, 70.3%) with a borderline association between high molecular risk mutations and overall survival.

CONCLUSIONS

This study, as one of the largest of MPN-U studies incorporating both clinicopathologic and molecular data, moves toward identification of biomarkers that better predict prognosis in this heterogeneous category.

DeepHeme: A generalizable, bone marrow classifier with hematopathologist-level performance

Morphology-based classification of cells in the bone marrow aspirate (BMA) is a key step in the diagnosis and management of hematologic malignancies. However, it is time-intensive and must be performed by expert hematopathologists and laboratory professionals. We curated a large, high-quality dataset of 41,595 hematopathologist consensus-annotated single-cell images extracted from BMA whole slide images (WSIs) containing 23 morphologic classes from the clinical archives of the University of California, San Francisco. We trained a convolutional neural network, DeepHeme, to classify images in this dataset, achieving a mean area under the curve (AUC) of 0.99. DeepHeme was then externally validated on WSIs from Memorial Sloan Kettering Cancer Center, with a similar AUC of 0.98, demonstrating robust generalization. When compared to individual hematopathologists from three different top academic medical centers, the algorithm outperformed all three. Finally, DeepHeme reliably identified cell states such as mitosis, paving the way for image-based quantification of mitotic index in a cell-specific manner, which may have important clinical applications.

OCCULT RECURRENT BREAST CANCER MASQUERADING AS THROMBOTIC THROMBOCYTOPENIC PURPURA

GATA3 immunohistochemistry stain of the bone marrow biopsy required to diagnose recurrent metastatic breast cancer.

Immune thrombocytopenia is associated with persistently deranged fibrosis-related seromarker profiles but low bone marrow fibrosis grades: A 2-year observational study on thrombopoietin receptor agonist treatment

Bone marrow (BM) fibrosis is a potential side effect of thrombopoietin receptor agonist (TPO-RA) treatment. We aimed to investigate stromal seromarker profiles and growth factors in order to elucidate pathogenic and dynamic aspects of immune thrombocytopenia (ITP)-related BM fibrosis before and during TPO-RA treatment. Connective tissue metabolites [procollagen I and III peptides (PINP/PIIINP); hyaluronan (HYA), C-terminal-telopeptide (ICTP), and fibrosis-related growth factors (transforming growth factor-beta (TGF-beta), HGF, basic fibroblast growth factor)] were measured in blood samples acquired before initiation of TPO-RA and subsequently at 6-month intervals for up to 2 years. BM fibrosis was graded MF-0 in 8 (18%), MF-1 30 (65%), and MF-2 8 (18%) in the last available BM biopsy. In the 21 patients having more than one biopsy, the grade of fibrosis from the first to the last available biopsy decreased in 2 (10%), remained unchanged in 15 (71%), and increased in 4 (19%). Pretreatment levels of PIIINP, PINP, ICTP, and HYA were significantly increased in ITP versus controls. PINP, PIIINP, and HYA decreased on TPO-RA; ICTP remained unchanged. PINP:ICTP was lower before and during treatment compared to controls. Pretreatment, TGF-beta was lower than in controls; HGF exhibited the opposite pattern. HYA, ICTP, and TGF-beta tended to increase while PINP and platelet-derived growth factor tended to decrease with increasing fibrosis grade. In conclusion, ITP is associated with deranged patterns of extracellular matrix seromarkers and growth factors, indicating that BM stromal remodeling is enhanced. During TPO-RA treatment for up to 2 years, this profile was partially reversed while mild BM reticulin fibrosis was still present in the majority of patients. These observations likely reflect a BM injury by autoimmunity that is modified by TPO-RA.

The myeloproliferative neoplasms, unclassifiable: clinical and pathological considerations

This corrects the article DOI: 10.1038/modpathol.2016.182.

Clonal reticulohistiocytosis of the skin and bone marrow associated with systemic mastocytosis and acute myeloid leukaemia

AIMS

The aims of this study were to define whether diffuse cutaneous reticulohistiocytosis could be underpinned by somatic genetic alterations and represent a precursor of more aggressive forms of disease.

METHODS AND RESULTS

A 59-year-old man with diffuse cutaneous reticulohistiocytosis experienced bone marrow localization of the disease, with associated systemic mastocytosis and acute myeloid leukaemia. Cytogenetic analyses of the bone marrow aspirate revealed the presence of a derivative chromosome giving rise to a partial trisomy of chromosome 1q and a partial monosomy of chromosome 9q. Therefore, we characterized the cutaneous lesions before and after chemotherapy by using an integrative approach combining histopathology, electron microscopy, and fluorescence in-situ hybridization. Histologically, the skin lesions belonged to the spectrum of diffuse cutaneous reticulohistiocytoses, as confirmed by immunohistochemistry and ultrastructural analyses. Fluorescence in-situ hybridization in the skin nodules confirmed the presence of the genetic alterations previously detected in the bone marrow.

CONCLUSIONS

Here, we provide circumstantial evidence to suggest that at least a subset of cutaneous reticulohistiocytoses harbour clonal molecular alterations. Furthermore, we confirm that these lesions have the potential to arise in the setting of concurrent haematological disorders. In this hypothesis-generating study, two possible tumorigenesis models are proposed.

The myeloproliferative neoplasms, unclassifiable: clinical and pathological considerations

In this study, we investigate in detail the morphological, clinical and molecular features of 71 consecutive patients with a diagnosis of myeloproliferative neoplasms, unclassifiable. We performed a meticulous morphological analysis and found that most of the cases displayed a hypercellular bone marrow (70%) with normal erythropoiesis without left-shifting (59%), increased granulopoiesis with left-shifting (73%) and increased megakaryocytes with loose clustering (96%). Megakaryocytes displayed frequent giant forms with hyperlobulated or bulbous nuclei and/or other maturation defects. Interestingly, more than half of the cases displayed severe bone marrow fibrosis (59%). Median values of hemoglobin level and white blood cells count were all within the normal range; in contrast, median platelets count and lactate dehydrogenase were increased. Little less than half of the patients (44%) showed splenomegaly. JAK2V617F mutation was detected in 72% of all patients. Among the JAK2-negative cases, MPLW515L mutation was found in 17% and CALR mutations in 67% of the investigated cases, respectively. Finally, by multiple correspondence analysis of the morphological profiles, we found that all but four of the cases could be grouped in three morphological clusters with some features similar to those of the classic BCR-ABL1-negative myeloproliferative neoplasms. Analysis of the clinical parameters in these three clusters revealed discrepancies with the morphological profile in about 55% of the patients. In conclusion, we found that the category of myeloproliferative neoplasm, unclassifiable is heterogeneous but identification of different subgroups is possible and should be recommended for a better management of these patients.

Neutrophilic leukocytosis in advanced stage polycythemia vera: hematopathologic features and prognostic implications

Polycythemia vera in 20-30% of cases progresses towards post-polycythemic myelofibrosis, an advanced phase characterized by decreased red blood cells counts and increasing splenomegaly with extramedullary hematopoiesis. There is evidence that the presence of neutrophilic leukocytosis at polycythemia vera disease outset is associated with an increased risk of recurrent thrombosis. However, its clinical significance when developing later in the course of the disease is not well defined. Over a period of 8 years we identified from the files of two reference centers 10 patients (7M/3F, median age: 68 years) who developed persistent absolute leukocytosis ≥ 13 × 10⁹/l (median: 25.1 × 10⁹/l; range: 16.1-89.7 × 10⁹/l) at or around the time of diagnosis of post-polycythemic myelofibrosis (median interval from diagnosis:0 months; range: -6/31) and persisted for a median period of 13 months. Peripheral blood smears showed numerous neutrophils without dysplastic features and, in four, ≥ 10% immature myeloid precursors. In five cases, corresponding marrow specimens obtained at or immediately after the onset of leukocytosis showed a markedly increased myeloid:erythroid ratio due to granulocytic proliferation. No change in JAK2 and BCR-ABL1 status or cytogenetic evolution was associated with the development of leukocytosis. The mutational status of CSF3R, SETBP1, and SRSF2, genes associated with other chronic myeloid neoplasms where neutrophilic leukocytosis occurs, was investigated but all cases showed wild-type only alleles. Four patients died after developing leukocytosis and one experienced worsening disease. Compared with a control group of post-polycythemic myelofibrosis patients (n=23) who never developed persistent leukocytosis, patients with leukocytosis showed higher white blood cells counts and a shorter overall survival. This is the first study describing the development of significant neutrophilic leukocytosis during advanced stages of polycythemia vera; it includes comprehensive hematologic, marrow morphological, molecular, and clinical data. Our findings suggest that persistent leukocytosis occurring at or around the time of progression to post-polycythemic myelofibrosis is associated with an overall more aggressive course of the disease.

Lenalidomide in patients with red blood cell transfusion-dependent myelodysplastic syndrome and del(5q): a single-centre "real-world" experience

"Real life" data are needed to complement published trials on the efficacy of lenalidomide in patients with myelodysplastic syndrome (MDS) and del(5q) and on the risk of inducing acute myeloid leukemia (AML) progression. Here, we present results of lenalidomide treatment in a consecutive, population-based series of 21 red blood cell (RBC) transfusion-dependent elderly patients with multiple comorbidities. Of 18 evaluable patients (median follow-up: 22 months), 17 achieved an erythroid hematologic response (HI-E) and 16 an RBC transfusion independence. Cytogenetic response (CyR) rate was 80%, median overall survival was 48 months (range 3-164), and 5-year leukemia-free survival was 84%. Three patients progressed to AML; one, with baseline TP53 mutation, achieved HI-E, partial CyR, and did not progress to AML. Eighteen patients experienced hematological adverse events. Overall, lenalidomide was very effective and well tolerated even in unselected elderly patients with multiple comorbidities and did not appear to increase the risk of AML.

The detection of SRSF2 mutations in routinely processed bone marrow biopsies is useful in the diagnosis of chronic myelomonocytic leukemia

Diagnosis of chronic myelomonocytic leukemia (CMML) is based on a combination of clinical, laboratory, and morphological parameters, including persistent peripheral blood monocytosis. Recently, mutations of serine/arginine-rich splicing factor 2 (SRSF2) have been identified in 40% to 50% of CMMLs and occasionally in other myeloid disorders. In this study, we established a robust assay for the detection of SRSF2 mutations in decalcified, paraffin-embedded bone marrow (BM) biopsies and investigated its diagnostic utility. BM biopsies of 78 patients with myeloid neoplasms, including 36 CMMLs, 22 myelodysplastic syndromes (MDS), and 20 Ph- myeloproliferative neoplasms (MPN) were analyzed. The region around hot spot P95 in exon 1 of SRSF2 was amplified and bidirectionally sequenced. In addition, a restriction fragment length polymorphism analysis was established. The JAK2 V617F mutation was investigated by allele-specific polymerase chain reaction. SRSF2 mutations were identified in 16 (44%) of 36 CMMLs, including 1 of 3 cases with associated systemic mastocytosis, 4 (20%) of 20 Ph- MPN, and 1 (4.5%) of 22 MDS. Restriction fragment length polymorphism analysis detected all mutations with the exception of a single P95A. Of note, 2 cases of JAK2 V617F+ primary myelofibrosis with SRSF2 mutation initially were diagnosed as CMML based on significant peripheral blood monocytosis. In CMML, no correlation with histopathology and/or clinical parameters was observed, but SRSF2 mutations were associated with normal karyotype (P < .001). In summary, SRSF2 mutations are frequent in CMML and a useful diagnostic feature demonstrable in BM biopsies, allowing a definitive diagnosis for cases with minimal dysplasia and normal karyotype. The role of SRSF2 mutations in cases with hybrid features between primary myelofibrosis and CMML needs further investigation.

Bone marrow fibrosis in 66 patients with immune thrombocytopenia treated with thrombopoietin-receptor agonists: a single-center, long-term follow-up

Thrombopoietin-receptor agonists increase platelet counts by stimulating the thrombopoietin receptor. Bone marrow fibrosis has been reported in patients receiving thrombopoietin-receptor agonists. This study determined the extent of myelofibrosis, its clinical relevance, and incidence of phenotypic or karyotypic abnormalities in patients with immune thrombocytopenia treated with thrombopoietin-receptor agonists. The grade of myelofibrosis was assessed before (n=15), during (n=117) and after (n=9) treatment in bone marrow biopsies from 66 patients. The proportion of bone marrow biopsies showing no fibrosis (myelofibrosis grade 0) decreased from 67% pre-treatment to 22% at last biopsy, of which 59% had grade 1 myelofibrosis and 18% had grade 2 myelofibrosis. The median duration of treatment with thrombopoietin-receptor agonists to last bone marrow biopsies was 29 months; patients who had two or more biopsies significantly more frequently had myelofibrosis grades 2/3 in the last bone marrow biopsies as compared to the first. Older age was associated with higher grades of fibrosis. No differences in blood counts or lactate dehydrogenase levels were found between patients with myelofibrosis grades 0/1 and those with grade 2. No clonal karyotypic or immunophenotypic abnormalities emerged. This study found that thrombopoietin-receptor agonists induce myelofibrosis grades 2/3 in approximately one-fifth of patients with immune thrombocytopenia, increasingly with >2 years of treatment with thrombopoietin-receptor agonists. Annual/biannual follow-up with bone marrow biopsies is, therefore, recommended in patients being treated with thrombopoietin-receptor agonists in order to enable prompt discontinuation of these drugs should grades 2/3 myelofibrosis develop. Discontinuation of thrombopoietin-receptor agonists may prevent development of clinical manifestations by stopping progression of fibrosis in grade 2/3.

High levels of vascular endothelial growth factor protein expression are associated with an increased risk of transfusion dependence in myelodysplastic syndromes

We evaluated the prognostic significance of vascular endothelial growth factor (VEGF) protein expression in 79 bone marrow biopsy specimens of patients with myelodysplastic syndromes (MDS). VEGF levels normalized for bone marrow cellularity (VEGF index [VEGFi]) were higher in the World Health Organization (WHO) classification-based prognostic scoring system (WPSS) "very high risk" than in the "very low risk" group (P = .009) and in patients with MDS with a poor karyotype than in the other cytogenetic risk groups (P = .015). High VEGFi (>75(th) percentile) predicted transfusion dependence (adjusted odds ratio, 10.38; 95% confidence interval, 1.02-106), and were correlated with leukemia-free survival and overall survival. The inclusion of VEGFi in the International Prognostic Scoring System and WPSS maintained its significant prognostic role in predicting leukemia-free and overall survival; it also seemed to improve the discrimination of the different prognostic classes, especially WPSS low-risk classes. Our findings support the clinical relevance of VEGFi expression in the bone marrow biopsy specimens of patients with MDS.

Development of monocytosis in patients with primary myelofibrosis indicates an accelerated phase of the disease

Primary myelofibrosis is a type of chronic myeloproliferative neoplasm characterized by progressive bone marrow failure with worsening cytopenia and in a subset of patients, progression to acute leukemia. Published data in patients with myelodysplastic syndromes have shown that the development of monocytosis in the course of myelodysplastic syndromes is associated with a poor prognosis. A similar occurrence has been only sporadically reported in patients with primary myelofibrosis. Over a period of four years we identified 10 out of 237 cases of primary myelofibrosis who developed persistent absolute monocytosis (>1 × 10(9)/l) during the course of disease (5 men and 5 women; median age/range: 68 years/52-82). Monocytosis developed at a median interval of 42 months from diagnosis (range: 1-180) and persisted for a median period of 23 months (range: 2-57). Five patients died after developing monocytosis (range: 20-188 months) and two experienced worsening disease and became transfusion dependent. Monocytosis was associated with increased white blood cells, decreased hemoglobin, decreased platelet count, and the presence of circulating blasts. In three cases, bone marrow biopsies after the onset of monocytosis showed marked myelomonocytic proliferation with morphological shifting from a typical primary myelofibrosis marrow appearance to aspects compatible with an overt 'secondary' chronic myelomonocytic leukemia. Before the development of monocytosis, 5 of 10 patients carried the JAK2V617F mutation; five patients showed karyotypic alterations. No change in JAK2 mutational status or cytogenetic evolution were associated with the development of monocytosis. Four of nine patients analyzed showed KRAS mutation in codon 12 or 13 with low allele burden. This is the first study correlating monocytosis developing in primary myelofibrosis patients with bone marrow morphology, laboratory data, molecular analysis and clinical follow-up. Development of monocytosis in patients with established primary myelofibrosis is associated with rapid disease progression and these patients should be considered as a high-risk group associated with short survival.

Composite chronic lymphocytic leukemia/small lymphocytic lymphoma and follicular lymphoma are biclonal lymphomas: a report of two cases

Composite lymphomas (CLs) consisting of 2 indolent B-cell lymphomas are rare. We present 2 CL cases composed of chronic lymphocytic leukemia (CLL) and follicular lymphoma (FL), each with unique clinicopathologic features. In the first case, the FL was negative for IGH-BCL2 and harbored a novel IGH-associated translocation; in the second case, the CL manifested in the skin. The individual components in both CLs were derived from different B-cell clones. This is the first complete characterization, including molecular analysis, of CLs composed of leukemic CLL and FL and the first report of a cutaneous CL derived from 2 low-grade B cell lymphomas. Our results provide additional supporting evidence that CLs of indolent B-cell lymphomas are biclonal and suggest that they are pathogenetically different from CLs composed of a low-grade B-cell lymphoma and an aggressive B-cell lymphoma or Hodgkin lymphoma, which are usually clonally related.

Thrombopoietin receptor agonist therapy in primary immune thrombocytopenia is associated with bone marrow hypercellularity and mild reticulin fibrosis but not other stromal abnormalities

Primary immune thrombocytopenia is an acquired autoimmune disorder characterized by platelet count of <100 × 10(9)/l in the absence of other causes of thrombocytopenia. Primary immune thrombocytopenia is defined as 'chronic' when it has been present for more than 12 months without spontaneous remission or maintenance of complete response to therapy. Recently, thrombopoietin receptor agonists became available for treatment of chronic primary immune thrombocytopenia. Anecdotal reports have raised concerns about a possible association between therapy with thrombopoietin receptor agonists and an increase in bone marrow fibrosis. To investigate this association we studied eight patients with primary immune thrombocytopenia in detail comparing fibrosis and other morphological features in pre-therapy and on-therapy bone marrow biopsies, with the longest follow-up reported to date. A slight but significant increase to MF-1 in reticulin fibrosis was observed during therapy, but collagen was never present. On-therapy bone marrows were hypercellular due to panmyelosis with increased trilineage hematopoiesis. Megakaryocytes were increased in number, with acquisition of evident pleomorphism, nuclear hyperlobulation and tendency in some cases to form clusters. The overall picture of the on-therapy marrows was characterized by myeloproliferative neoplasm-like features, resembling essential thrombocythemia or occasionally early primary myelofibrosis. As thrombopoietin receptor agonists are becoming a mainstream treatment for primary immune thrombocytopenia, general pathologists and especially hematopathologists need to be aware of the characteristic morphological changes associated with use of these therapeutic agents, in order to avoid misdiagnosis of a myeloid neoplasm.

Tracheal melanic tattoo

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Increased expression of vascular endothelial growth factor receptor 1 correlates with VEGF and microvessel density in Philadelphia chromosome-negative myeloproliferative neoplasms

Aims

The authors investigated vascular endothelial growth factor receptor 1 (VEGFR-1) protein expression in a series of Philadelphia chromosome-negative myeloproliferative neoplasms (Ph- MPNs) and its correlations with microvessel density (MVD) and vascular endothelial growth factor (VEGF).

Methods

83 bone marrow biopsies of Ph- MPNs patients, including 27 essential thrombocythaemia (ET), 21 polycythaemia vera (PV) and 35 primary myelofibrosis (PMF), and 10 normal controls (NCs) were investigated by immunohistochemistry.

Results

Patients with PV and PMF showed an increased MVD (PV: 20.1±10.6; PMF: 25.8±6.5) compared with those with ET or NCs (ET: 10.4±4.6; NCs: 7±3.4). VEGFR-1 expression was increased in Ph- MPNs, particularly in PV and PMF (NCs: 0.07±0.03; ET: 0.15±0.09; PV: 0.31±0.2; PMF: 0.31±0.04). VEGF expression parallelled VEGFR-1 and resulted increased in Ph- MPNs (NCs: 0.08±0.04; ET: 0.13±0.06; PV: 0.29±0.2; PMF: 0.31±0.15) and higher in post-polycythaemic myelofibrosis and in the fibrotic stage of PMF than in the non-fibrotic phases of both diseases. VEGFR-1 protein expression correlated with MVD and VEGF expression in Ph- MPNs. VEGFR-1 and VEGF were expressed by the same bone marrow populations: megakaryocytes, macrophages and immature myeloid precursors showed a moderate to strong immunostaining intensity in both Ph- MPNs and NCs. The erythroid precursors were not immunoreactive.

Conclusions

VEGFR-1 and VEGF were increased and co-localised in megakaryocytes, macrophages and myeloid precursors of Ph- MPNs. This finding supports the hypothesis of a VEGF/VEGFR-1 autocrine loop in the neoplastic cells of Ph- MPNs.

Prostatic stromal tumor with fatal outcome in a young man: histopathological and immunohistochemical case presentation

Stromal tumors of the prostate are rare and only a few cases have been described in the literature, including exceptional cases of stromal tumors with unknown malignant potential (STUMP) and a fatal outcome in young patients. Morphologically distinguishing a STUMP from a stromal sarcoma of the prostate (PSS) is still a challenge. We describe the histopathological and immunohistochemical findings in a 34-year-old man with a malignant specialized cell stromal tumor of the prostate that was diagnosed initially as STUMP, and he developed lung metastases within a few months. The patient attended our hospital because of lower urinary tract symptoms, after having excreted tissue through the urethra a few months before. Ultrasonography and urethrocystoscopy examinations showed a mass arising from the verumontanum, and a transurethral resection (TUR) revealed a highgrade spindle cell sarcoma reminiscent of a phyllode tumor of the breast. The tumor cells were immunoreactive for vimentin, progesterone receptor and, focally, CD34. The preliminary histological findings were subsequently confirmed after radical prostatectomy. The patient developed bilateral lung metastases and died 25 months after the initial diagnosis. Although rare in young patients, the challenging differential diagnosis of STUMP and PSS means that a prostate STUMP diagnosis made on the basis of biopsy or TUR specimens also requires urethrocystoscopic monitoring for the early detection of any progression to PSS. Radical prostatectomy should also be carefully considered.