| Session: Myelodysplastic / myeloproliferative disease |
| Case number: 128 |
Submitter(s): Rebecca F. McClure.
Clinical history
70 year old male found to have anemia and thrombocytosis several years ago during an episode of diverticulitis. The anemia was unsuccessfully treated with iron but he has had no further hematologic evaluation/therapy. He has no other significant medical history and takes no medications. He now presents for routine colonic surveillance.
His physical exam is normal and no hepatosplenomagaly is detected by imaging. Diverticulosis is stable with no bleeding identified.
Details of gross/microscopic pathology:
Blood CBC: Hb 11.4 g/dL; RBC 3.55 x 1012/L; MCV 98.2 fL; RDW 29.9%; WBC 8.3 x 109/L; Plt 609 x 109/L
Blood Absolute Counts: neutrophils 4.5 x 109/L; metamyelocytes 0.08 x 109/L; lymphocytes 2.3 x 109/L; monocytes 0.58 x 109/L; eosinophils 0.25 x 109/L; basophils 0.33 x 109/L
Blood Morphology: Macrocytic anemia with marked anisocytosis (hypochromic microcytes, round and oval macrocytes, slight polychromasia) and slight poikilocytosis (target cells). Occasional cells with course stippling and occasional circulating nucleated RBCs are present. Some neutrophils have nuclear hyposegmentation and occasional circulating neutrophil precursors are present. Eosinophils, basophils, monocytes and lymphocytes have normal cytology. There is thrombocytosis with normal platelet morphology.
Bone Marrow Aspirate Morphology: Cellular, with an estimated M:E ratio of 1:1. Erythroid precursors are proportionately increased with mild megaloblastoid maturation and some cytoplasmic stippling. Megakaryocyte cytology is mildly atypical with occasional large cells containing hyperlobated nuclei. Some neutrophil precursors have mild nuclear hyposegmentation. Other granulocytes, monocytes, lymphocytes, plasma cells and blasts are all present in normal proportions and show normal cytology.
Normal stainable iron with the majority of erythroid precursors being ringed sideroblasts (iron stain).
Mild increase in dual esterase positive cells (dual chloroacetate/butyrate esterase stain).
Bone Marrow Biopsy: Hypercellular (80-90%) with panmyeloid hyperplasia but with erythroid precursors and megakaryocytes increased to a greater extent than the other myeloid cell lines. Megakaryocytes are atypical (some large, course chromatin, vague clustering). There is no increase in lymphocytes, plasma cells or blasts.
Bone trabeculae are normal.
There is no increase in reticulin (reticulin stain).
Immunophenotype (flow cytometry/immunohistochemistry):
No immunophenotyping was performed.
Cytogenetics:
Karyotype: Normal (46,XY in 20 of 20 metaphases).
Molecular analysis:
JAK2 V617F (sequencing): Positive.
Interesting feature(s) of submitted case:
A mixed MDS/CMPD with features of a controversial diagnostic category: the proposed WHO category of "Refractory anemia with ringed sideroblasts associated with marked thrombocytosis". The biology, diagnostic features and clinical characteristics of this potential category require discussion and clarification.
Proposed diagnosis:
Descriptive until further characterized:
Mixed MDS/CMPD with thrombocytosis; JAK2 V617F positive.
Panel diagnosis:
More prominent features of myeloproliferative disease such as CIMF/PMF
Comments:
Stains performed by the panel: CD34 within normal limits, hemoglobin 60% of the cellularity
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