| Session: Ph- chronic myeloproliferative disease |
| Case number: 127 |
Submitter(s): Rebecca F. McClure.
Clinical history
64 year old female with a long history of tobacco abuse being evaluated for elevated liver enzymes. Noted to have erythrocytosis. No prior CBCs were available for review, but the patient recalls beign told she had "too many red blood cells" in the past. There is no known lung pathology. She was treated in the past for both esophagel carcinoma (8 years ago) and vulvar carcinoma (3 years ago). She takes no regular medication. After clinical work-up for secondary causes of erythrocytosis, the presumptive diagnosis was polycythemia vera.
Details of gross/microscopic pathology:
CBC: Hb 20 g/dL; Hct 58.8%; RBCs 6.2 x 1012 /L; MCV 94 fL; RDW 14.3%; WBC 10.8 x 109 /L; Plt 472 x 109 /L
Blood Absolute values: neutrophils 7.45 x 109 /L; monocytes 0.52 x 109 /L; lymphocytes 2.71 x 109 /L; basophils 0.07 x 109 /L; eosinophils 0.04 x 109 /L
Absolute reticulocytes: normal
Ferritin: 86 ug/L (normal 20-200)
Erythropoietin: 3.1 mIU/L (normal range 4-21)
Blood smear morphology: Essentially normal.
Bone marrow aspirate differential: neutrophils 20%; metamyelocytes 10%; myelocytes 12%; promyelocytes 2%; eosinophils 3%; blasts 1%; normoblasts 30%; monocytes 4%; lymphocytes 16%; plasma cells 2%
Bone marrow aspirate morphology: Cellular, with an estimated M:E ratio of 2:1 and esentially normal appearing hematopoiesis. Stainable iron was reported as absent (no stain available for review).
Bone marrow biopsy morphology: Normocellular bone marrow (30-40%) with normal-appearing hematopoiesis.
Immunophenotype (flow cytometry/immunohistochemistry):
No immunophenotyping was performed.
Cytogenetics:
Karyotype on bone marrow: Normal, 46,XX in 20 of 20 metaphases.
Molecular analysis:
BCR/ABL (bone marrow)(FISH): Negative
JAK2 mutation analysis (bone marrow): Reported as negative (detection method not known). At Mayo, an atypical melting curve was obtained when testing was done using a melting curve method. Sequencing revealed not only the classical G>T mutation at position 1849, which produces the V716F mutation, but two additional mutations: C>T at position 1851 and T>C at position 1852. These mutations result in 2 consecutive amino acid substitutions.
These additional mutations would be expected to interfere with primer binding and cause most standard JAK2 V617F mutation tests to appear negative.
Interesting feature(s) of submitted case:
Polycythemia vera containing the JAK2 V617F mutation and 2 additional mutations, which caused common mutation tests to appear negative for mutation.
Proposed diagnosis:
Polycythemia vera containing atypical JAK2 mutations.
Panel diagnosis:
agree with proposed diagnosis
Comments:
Panel comment: Detailed information regarding previous therapy for esophageal and vulvar carcinoma is essential.
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