| Session: Extramedullary manifestation of neoplastic myeloid disorder |
| Case number: 108 |
Submitter(s): Robert P. Hasserjian.
Clinical history
80 year old female presenting for management of Langerhans cell histiocytosis diagnosed on a skin biopsy one month ago. Inguinal, axillary, and occipital lymphadenopathy noted on exam as well as diffuse morbilliform skin rash. WBC 29.3 x 109 (69% polys, 8% bands, 6% lymphs, 2% atyps, 4% monos, 5% myelos, 6% metas) HGB 9.4 gm/dl, PLT 174 x 109.
Details of gross/microscopic pathology:
Examination of the peripheral smear reveals dysplastic neutrophils and precursors with hypogranulation and abnormal nuclear lobation (Figure 1). The bone marrow aspirate showed a predominance of maturing myeloid elements with abnormal nuclear features and hypogranulation, with generally normal erythroid maturation. The bone marrow core biopsy is 95% cellular with increased myeloid:erythroid ratio, increased early myeloid forms and scattered small, dysplastic megakaryocytes (Figure 2). An excised axillary lymph node (slides submitted) is replaced by sheets of immature and maturing myeloid elements as well as occasional erythroid elements and rare megakaryocytes (Figure 3) Also present are intrasinusoidal and aggregated nodules of large cells with irregular and grooved nuclei and abundant pink cytoplasm (Figure 4,5).
Immunophenotype (flow cytometry/immunohistochemistry):
By immunohistochemistry on the axillary node, the myeloid elements are CD68 positive, with only rare CD117 and CD34 positive blasts. Hemoglobin and glycophorin highlight scattered erythroid elements. The nodules of large cells are strongly positive for S-100 and CD1a (Figure 6,7).
Cytogenetics:
Cytogenetics of bone marrow: 47, XX, +8. FISH for BCR-ABL is negative.
Touch preparation of the axillary lymph node: Interphase FISH shows trisomy 8 in 35/114 nuclei.
A touch preparation of the axillary lymph node was stained for CD1a (green immunofluorescence) and FISH was then performed for the chromosome 8 centromere (red). This reveals several CD1a positive cells showing three chromosome 8 signals, consistent with presence of trisomy 8 in the Langerhans cells in the axillary lymph node (Figure 8).
Molecular analysis:
None.
Interesting feature(s) of submitted case:
The Langerhans cell histiocytosis in the axillary lymph node was shown by combined immunofluorescence and FISH to bear the same +8 abnormality as the patient's myelodysplastic/myeloproliferative disease, demonstrating a clonal relationship between these disorders. Langerhans cells proliferations have been described in association with Hodgkin and non-Hodgkin's lymphomas, in which they are assumed to be reactive (clonally unrelated to the neoplasm). To our knowledge, this is the first report of a Langerhans cell proliferation which has been shown to be clonally related to a concurrent myeloid neoplasm.
Proposed diagnosis:
Atypical chronic myeloid leukemia with differentiating extramedullary myeloid sarcoma.
Langerhans cell histiocytosis, involving skin and lymph nodes, clonally related to the atypical chronic myeloid leukemia.
Panel diagnosis:
agree with proposed diagnosis
Comments:
Stains performed by the panel: CD1a+ in Langerhans cells, MPO+ in myeloid precursors, NPM- (+in nuclei)
Images:
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