| Session: Mast cell disease |
| Case number: 056 |
Submitter(s): Sheeja T. Pullarkat, Franklin Sedarat, Jonathan Said.
Clinical history
84-year-old man presented with anemia, 20 lbs weight loss, skin rash and was found to have monoclonal gammopathy. No hepatosplenomegaly or lytic bone lesions were present. Laboratory studies were significant for hemoglobin of 9g/dl and serum tryptase of greater than 200 ng/ml.Immunoglobulin quantitation showed- IgG: 2530 mg/dl, IgA: 94 mg/dl and IgM: 27mg/dl.
Medications- Famotidine, Lasix, Advair, albuterol, Lipitor, Zoloft.
Details of gross/microscopic pathology:
Bone marrow aspirate smear/ imprint morphology (Figures 3 and 4)
Myeloid prepondrance with left shifted granulopoeisis. The erythroid maturation was orderly. There was increased numbers of mast cells many of which were atypical with uneven cytoplasmic granules. Plasma cells were increased in number (10%) and many had vacuolated cytoplasm.The megakaryocytes were mildly increased in number and were normal in morphology. Iron stores and incorporation were decreased.
Bone marrow trephine biopsy morphology
The B5-fixed bone marrow biopsy was markedly hypercellular (80-90%). All hematopoetic elements were present and displayed progressive maturation. There were increased numbers of spindle shaped mast cells (Figure 1). These cells had elongated nuclei, fine chromatin, and moderate to abundant amounts of cytoplasm and were arranged in a paratrabecular and perivascular fashion in a fibrotic background (Figure 5). Increased numbers of eosinophils were seen around these aggregates. In addition, increased numbers of plasma cells in clusters were also seen. The trabecular bone was thickened adjacent to the mast cell aggregates.
Immunophenotype (flow cytometry/immunohistochemistry):
The mast cells were positive for tryptase, CD117 and CD2 (Figures 7-9). In addition, the CD 138 positive plasma cells constituted about 10% of the bone marrow cells and showed lambda monotypic staining (Figures 10, 6). Increased reticulin fibrosis was also evident (Figure 2).
Cytogenetics:
46XY.
Molecular analysis:
Positive for KIT mutation D816V.
Interesting feature(s) of submitted case:
Systemic mastocytosis with associated lymphoproliferative disease is rare. A review of the literature shows only four reported cases of SM with plasma cell disorders. The case provides an oppurtunity to discuss the clinical features and pathogenesis of SM with associated lymphoproliferative disease and contrast these with SM associated with myeloid malignancies.
Proposed diagnosis:
SM-AHNMD: Systemic mastocytosis with plasma cell dyscrasia (monoclonal gammopathy of undetermined significance).
Panel diagnosis:
SM-AHNMD/MGUS or plasma cell myeloma
Comments:
Studies performed by the panel: WT c-kit, CD25+
Images:
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