All posts by peferguson

Organ Systems, Bone Marrow, WHO Classification, MPN, Hematopathology

MF3 – Reticulin Fibrosis

Diffuse increase of reticulin fibers with increased density and numerous intersections.  Increased thick bundles of fibers consistent with collagen fibrosis.  Osteosclerosis usually present.

Photomicrographs
Reticulin - MF3 fibrosis
Reticulin – MF3 fibrosis
Reticulin - MF3 fibrosis
Reticulin – MF3 fibrosis
Trichrome - MF3 fibrosis
Trichrome – MF3 fibrosis
Trichrome - MF3 fibrosis
Trichrome – MF3 fibrosis
References
Swerdlow SH, Campo E, Harris, NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):  WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition). IARC: Lyon 2017
 
Arber DA, Orazi A, Hasserjian R, Thiele J, Borowitz MJ, Le Beau MM, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016;127: 2391–2405. doi:10.1182/blood-2016-03-643544
Organ Systems, Bone Marrow, WHO Classification, MDS, Hematopathology

MDS Cytogenetics

The following are cytogenetic abnormalities that are considered as presumptive evidence of MDS in the setting of persistent cytopenias:
 
-7 or del (7q)
-5 or del(5q)
i(17q) or t(17p)
-13 or del(13q)
del(11q)
del(12p) or t(12p)
del(9q)
idic(X)(q13)
t(11;16)(q23;p13.3)
t(3;21)(q26.2;q22.1)
t(1;3)(p36.3;q21.2)
t(2;11)p21;q23)
inv(3)(q21q26.2)
t(6;9)(p23;q34)

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Organ Systems, Breast

Breast Myofibroblastoma

Myofibroblastoma (MFB) of the breast is an uncommon but well described benign stromal neoplasm of the breast.  MFB can have many different morphologic patterns (see variants below), but important defining characteristics include:

  • Mesenchymal tumor without epimyoepithelial elements
  • No necrosis
  • Low proliferative activity (≤2 mitoses/10 hpf)
  • No atypical mitoses
  • Characteristic immunophenotype

Continue reading Breast Myofibroblastoma →

Acute Leukemia, Organ Systems, Bone Marrow, WHO Classification, Hematopathology

Acute Undifferentiated Leukemia

A vary rare acute leukemia that does not express markers considered specific for lineage determination. (e.g. MPO, esterase, cCD3, cCD22, strong CD19, etc.).  Typically there will be one or less lineage markers for any lineage.  CD34, HLA-DR, and TdT may be expressed, but are not specific for any lineage.
 

Care should be taken that immunophenotyping panels are extensive, and consideration is given to other entities such as plasmacytoid dendritic precursors, non-hematopoietic tumors, NK-cell precursors, etc.  Essentially, a diagnosis of exclusion.

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Organ Systems, Bone Marrow, WHO Classification, Hematopathology, Acute Leukemia

Myeloid/Lymphoid Neoplasms Associated with Eosinophilia

  • PDGFA
    • Eosinophilia with increased tryptase and marrow mast cells
    • Cryptic deletion in chromosome 4q12
    • FIP1L1-PDGFA, many other partners
    • Responsive to tyrosine kinase inhibitors (e.g. imatimib/Gleevec®)
  • PDGFB
    • Eosinophilia combined with monocytosis that mimics CMML
    • t(5;12)(q31;33;p12) ETV6-PDGFB, many other partners
    • Responsive to TKIs 
  • FGFR1
    • Eosinophilia combined with AML or T-ALL
    • Associated with 8p11 translocations, FGFR1 with multiple partners
    • Not responsive to TKIs (poor prognosis)
  • PCM1-JAK2 (provisional entity)
    • Eosinophilia along with acute lymphoblastic leukemia (B-cell) or lymphoma (T-cell)
    • Bone marrow with lymphoid aggregates and increased/left shifted erythroid precursors (mimics PMF)
    • May respond to JAK2 inhibitors (e.g ruxolitinib/Jakafi®)
References

Arber DA, Orazi A, Hasserjian R, Thiele J, Borowitz MJ, Le Beau MM, et al. The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia. Blood. 2016;127: 2391–2405. doi:10.1182/blood-2016-03-643544

Swerdlow SH, Campo E, Harris, NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):  WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition). IARC: Lyon 2017

Hematopathology, Organ Systems, Bone Marrow, Multiple Myeloma, WHO Classification

Smoldering (Asymptomatic) Myeloma 

Smoldering (Asymptomatic) Myeloma 
  • >3 gm/dL serum M protein (or) urinary M protein ≥500 mg/24 hours
  • (and/or) 10-60% bone marrow plasma cells (usually 10-20% plasma cells)
  • Asymptomatic patients with no evidence of end-organ damage or biomarker evidence of malignancy (myeloma-defining events)

Continue reading Smoldering (Asymptomatic) Myeloma  →