Reactive cytopenia

Institute of Pathology and Medical Genetics

Alexandar Tzankov

Enterprise | Interest

None

Outline

• Background

indications and expectations towards bone marrow biopsies in cytopenia

• Practical approach to bone marrow biopsies in cytopenia

• Take homes

• Please notice the e-handout; PDF of the presentation freely available

Outline

• Background

indications and expectations towards bone marrow biopsies in cytopenia

• Practical approach to bone marrow biopsies in cytopenia

• Take homes

Bone marrow biopsies (BMB) in cytopenia:indications and expectations

• Common indication for trephine bone marrow biopsy

• Part of a multimodal approach for as specific as possible diagnosis

Bone marrow biopsies in cytopenia:expectations of pathologists to clinicians

• Anamnestic hints any suspicion of congenital / inherited / constitutional / genetic disease

any acute toxic or drug exposure, any previous chemo- or/and radiotherapy

any underlying systemic disease (e.g. collagenoses, systemic infections etc.)

duration

• Basic laboratory parameters and hints from the clinical examination blood cell counts and differential hemogram

iron / folic acid / vitamin B12 / copper status

findings suggesting autoimmune hemolysis or hemophagocytic lymphohistiocytosis

fever, splenomegaly, hepatomegaly, lymphadenopathy, relevant skin findings

any hints suggesting infection / nephropathy / hepatopathy / pneumopathy

Bone marrow biopsies in cytopenia:expectations of clinicians to pathologists

• Irreplaceability of the histopathological work-up

focal processes

o focal blast (islets)

fibrosing processes

o dry tap

o occasionally, the only specimen available for molecular work-up

disorders extrinsic to the bone marrow

o infections

o metastases

o granulomatous myelitis

o thrombotic microangiopathy

o etc.

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Outline

• Background

indications and expectations towards bone marrow biopsies in cytopenia

• Practical approach to bone marrow biopsies in cytopenia

• Take homes

• Histopathological pattern-based and blood count-based approach

• Constitutional bone marrow failures will not be specifically addressed in this lecture but can be found in the PDF of the presentation

My approach to reactive cytopenia

Pancytopenia – general considerations

• Clear indication for biopsy part of the disease definition

often dry taps (no other diagnostic specimen except for the BMB)o cutting-edge molecular diagnostic methods available and applicable

plethora of significant (focal) and to a part treatable underlying disorderso significant expectations of clinicians to pathologists

particular inflammatory patterns (e.g. granulomas)

specific infections (e.g. virocytopathic changes)

(autoimmune) myelofibrosis

microangiopathic changes

underlying malignancies

metabolic diseases

o unawareness of clinicians that most diagnoses can be established only in an integrative way underestimation of the effects of drugs/toxic exposures (e.g. idiopathic vs. secondary AA)

Pancytopenia with bone marrow hypo-/aplasia

• Aplastic anemia (AA) definition

Fanconi-, SDS- and DC-patients at risk

• Pitfalls subcortical pseudohypolasia

hypoplastic MDS/AML/ALL/lymphoma

Am J Clin Pathol. 2013;139:9-29.

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Secondary AA - expectations of pathologists to clinicians

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• Proliferation and/or survival pressure on hematopoietic stem cells 50% of AA patients have

clonal hematopoiesis• commonly affected: PIGA or

BCOR/BCORL1, and DNMT3Aor ASXL1

• rare mutations in TET2, TP53, RUNX1 and splicing factor genes

• +6 or +15, and +8, -7 and del(5q)

AA – from pathogenesis to molecular testing

Blood. 2016;128:337-47.

Pancytopenia with increase of histiocytes (± hemophagocytosis)

• Hemophagocytic lymphohistiocytosis

Am J Clin Pathol. 2013;139:713-27.

EBER/CD3

Hemophagocytic lymphohistiocytosis

J Clin Pathol. 2016;69:805-9.

Pitfalls

• post-transfusion changes

• post-myeloablative changes

• storage disorders

•metabolic disorders

• infections

• histiocytic neoplasms

Bicytopenia with bone marrow necrosis or microangiopathic changes

• Endothelial damage

carcinoma dissemination

hemolytic-uremic syndrome

transplant-associated microangiopathy

thrombotic-thrombocytopenic purpura

Anemia – general considerations

• Subject of laboratory medicine definitions normo-/hyper-/hypochromic, normo-/macro-/microcytic

± reticulocyte count changes

etc. …

• Generally not an indication for biopsy

• Unless long-lasting and/or severe

suspect of malignancy

treatment-resistant

unexplained

Anemia with erythroblastopenia

• Pure red cell aplasia alloimmune in HCT over the ABO-barrier

drug-induced (e.g. phenytoin)

idiopathic (autoimmune)

paraneoplastic o thymoma

o T-LGL LPD

• Parvovirus B19 infection

• Transient erythroblastopenia

of childhood (2-y-aged)Gly-A

Anemia with increased erythroid precursors

• Intrinsic or acquired erythroid survival and maturation defects

vitamin and/or other substrates deficiency

hemoglobinopathies, thalassemias & CDA

(autoimmune) hemolytic anemias

membrane defects incl. PNH

enzyme defects

…

medications antagonizing folate-, purine-and pyrimidine metabolism (allopurinol!)

Anemia of aging / of chronic disease

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• Integrative diagnosis

• Multifactorial disease(s)

• Non-specific findings

often hypercellularity & dysplasia

increased (stainable) iron

polytypic plasmacytosis

• Key features of significant underlying diseases?

occult neoplasm

chronic/specific infection

(autoimmune) myelofibrosis

renal/parathyroid osteopathy

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Neutropenia – general considerations

• Neutrophils <500/μl

• Often in acute viral infections

• Generally not an indication for biopsy

• Unless long-lasting

unexplainedo usually incomplete anamnesis

suspect of malignancyo T-LGL LPD

o others

Neutropenia with myeloid hypoplasia or maturation disturbance

• Drug toxicities (arylamine-containing drugs)

• Infections or autoimmunity

PAS

Pitfall: neutropenia with increased lymphocytes• T-LGL (LPD)

pSTAT3

Neutropenia with granulocytic hyperplasia

• Increased consumption of mature granulocytes in the periphery autoimmune neutropenia (of childhood)

septic conditions

• Pitfalls steroids

growth factors

MPO

Pitfall: neutropenia with myeloid hyperplasia• APML

CD117+

CD2+

FISH+

Leukemia. 1994;8:1108-12.Am J Clin Pathol. 2002;118:31-7.

Thrombopenia – general considerations

• <150.000/µl

• Generally not an indication for biopsy

• Unless unexplained

treatment-resistant

long-lasting and/or severe

suspect of malignancyo B-cell lymphomas

o MDS

o others

Thrombopenia with decreased megakaryocytes

• AA

• Toxic myelopathy (chemotherapy, mycophenolate, mTOR-inhibitors …)

• Virus infection (HIV, CMV)

• Autoimmunity with anti-C-MPL abs.

• Pitfall MDS

Thrombopenia with increased megakaryocytes

• “Megakaryocytic thrombopenia”

• Increased peripheral platelet consumption infections/septic conditions

mechanic destruction

ITP

HIT

TTP

DIC

PAS

MPN-like changes after THPO/THPORA-therapy!

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Monocytopenia = don’t miss the “hairy cells”!

AJSP. 2012;36:1796-800. CD103

BRAF V600E

Outline

• Background

indications and expectations towards bone marrow biopsies in cytopenia

• Practical approach to bone marrow biopsies in cytopenia

• Take homes

Summary: BMB in cytopenia

• Part of multimodal diagnostic process in cytopenia

obligatory diagnostic procedure in pancytopenia

important diagnostic procedure in (unexplained) cytopenia

• Irreplaceable in focal, fibrosing and non-hematopoietic diseases

• Useful guidance for our clinical colleagues and patients, particularly if

known caveats considered

ancillary techniques purposefully deployed

morphologic patterns and phenotypic findings properly interpreted

• Li KD, Salama ME. Therapy effect: Impact on bone marrow morphology. Surg Pathol Clin. 2016;9:177-87.

• Tzankov A, Dirnhofer S, Beham-Schmid C. Normal bone marrow and common reactive alterations. Pathologe. 2012;33:496-507.

• Ogawa S. Clonal hematopoiesis in acquired aplastic anemia. Blood. 2016;128:337-47.

• Tzankov A, Medinger M. Aplastic anemia: possible associations with lymphoproliferative neoplasms. Int J Lab Hematol. 2014;36:382-7.

• Rosado FG, Kim AS. Hemophagocytic lymphohistiocytosis: an update on diagnosis and pathogenesis. Am J Clin Pathol. 2013;139:713-27.

• Weinzierl EP, Arber DA. The differential diagnosis and bone marrow evaluation of new-onset pancytopenia. Am J Clin Pathol. 2013;139:9-29.

• Leguit RJ, van den Tweel JG. The pathology of bone marrow failure. Histopathology. 2010;57:655-70.

• Foucar K, Reichard K, Czuchlewski D. Bone marrow pathology. 3rd ed. Chicago, ASCP Press; 2010.

• Chang KL, Gaal KK, Huang Q, Weiss LM. Histiocytic lesions involving the bone marrow. Semin Diagn Pathol. 2003;20:226-236.

• Diebold J, Molina T, Camilleri-Broët S, Le Tourneau A, Audouin J. Bone marrow manifestations of infections and systemic diseases observed in bone marrow trephine biopsy review. Histopathology. 2000;37:199-211.

Helpful references

This is a rough practical sketch without any claim of being complete.

For comprehensive information I kindly refer to:• Foucar K, Reichard K, Czuchlewski D. Bone marrow pathology. 3rd ed. Chicago, ASCP Press; 2010.

• Iwafuchi H. The histopathology of bone marrow failure in children. J Clin Exp Hematop. 2018;58:68-86.

• Adam S, Melguizo Sanchis D, El-Kamah G, Samarasinghe S, Alharthi S, Armstrong L, Lako M. Concise Review: Getting to the core of inherited bone marrow failures. Stem Cells. 2017;35:284-98.

• Khincha PP, Savage SA. Genomic characterization of the inherited bone marrow failure syndromes. Semin Hematol. 2013;50:333-47.

• Leguit RJ, van den Tweel JG. The pathology of bone marrow failure. Histopathology. 2010;57:655-70.

Addendum: practical approach to congenital cytopenias

Congenital anemias

• Low reticulocytes, normal erythrocyte morphology, erythroid hypo-/aplasia = proliferation defects– Constitutional

• Fanconi anemia (+systemic/anatomic abnormalities)– chromosomal breakage (13 different genes)

• Diamond-Blackfan anemia (+systemic/skeletal abnormalities)– ribosomal biogenesis failure (9 different genes)

• Shwachman-Diamond syndrome (+neutropenia/pancreatic insufficiency)

• Dyskeratosis congenita (+cutaneous/nail/pulmonary abnormalities)– telomere maintenance failure (6 different genes)

– Acquired• Transient erythroblastopenia of childhood (+neutropenia)

– older than 1Y, HHV6, Parvo B19

Congenital anemias

• Low reticulocytes, macrocytosis, dysmorphy, erythroid hyperplasia = maturation defects

– Constitutional• Congenital dyserythropoietic anemias

– mitotic defects due to mutations of genes responsible for the nuclear integrity nuclear budding, bi-/mutinucleated forms, karyorrhexis

• Congenital megaloblastic anemia

– Gastric Intrinsic Factor mutation

– Transcobalamin II mutation

Congenital anemias

• High reticulocytes, dysmorphy, erythroid hyperplasia = hemoglobinization-, membrane- or enzyme defects (decreased life-span)– Constitutional

• Thalassemias and sickle cell disease

• Congenital sideroblastic anemias– heme synthesis genes (erythropoietic protoporphyria) or mitochondrial

DNA defects (Pearson syndrome) ring sideroblasts

• Sphero-/elliptocytosis

• G6PDH deficiency

– Acquired• TTP

Congenital neutropenias

• Low granulocytes, hyperplastic and left-shifted myelopoiesis = decreased life-span

– Acquired• Alloimmune, perinatal (anti-CD16b)

• Maternal drug exposure

• Autoimmune (anti-CD16b) (+emperipolesis of granulocytes in BM)

– 5-15 months of age

– Constitutional• Accompanying immunoglobulin deficiency syndromes

Congenital neutropenias

• Low granulocytes, hyperplastic and right-shifted myelopoiesis = decreased release

– W(arts)H(ypogamma)I(nfections)M(yelokathexis) syndrome• CXCR4 mutation (retention in BM

hypersegmentation/filamentous nuclear strands

– Chediak-Higashi (+large inclusions even in Ly, albinism)

Congenital neutropenias

• Low granulocytes, hypo-/aplastic (and left-shifted) myelopoiesis = decreased production– Acquired

• Viruses (CMV trough CD13, HIV, EBV, Parvo B19)

• Drugs (genetic metabolization defects)

– Constitutional• Shwachman-Diamond syndrome (+anemia, pancreatic insufficiency,

chondrodysplasia)– SBDS mutation (nucleolus & mitotic dysfunctions)

• Severe or cyclic congenital neutropenia– ELANE or HAX1 mutations (elastase misfolding, anti-apoptotic failure increased intramedullary neutrophilic apoptosis); GCSF sensitive

– CSF3R mutations – GCSF-resistant

• Fanconi & Dyskeratosis congenita

Congenital thrombopenias

• Low platelets, hypo-/amegakaryopoiesis = proliferation defects/amegakaryocytic thrombopenia

– Acquired (viruses)

– Constitutional• Fanconi, Dyskeratosis congenita, Shwachmann-Diamond syndrome

• Thrombocytopenia with absent radii syndrome

• Congenital amegakaryocytic thrombopenia

– MPL mutation (THPO high, no response to THPO)

Congenital thrombopenias

• Low platelets, increased megakaryopoiesis = increased consumption/megakaryocytic thrombopenia

– Acquired• Alloimmune

• Parainfectious

– Constitutional• With large platelets

– Grey platelet syndrome and other (GATA1, MYH9 … mutations) platelet defects (+myelofibrosis, ± hypo-/alobated megas)

• With small platelets

– Wiskott-Aldrich syndrome (+eczema & infections, hypolobated megas)