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Posted by on Jul 10, 2013 in Blog |

Yet Another Bone Marrow Biopsy


Peripheral blood and bone marrow, biopsy, clot and aspirate:

  1. Normocellular marrow with trilineage hematopoiesis and adequate storage iron.
  2. Few multifocal atypical mast cell infiltrates (5%). See comment


This is a normocellular marrow with trilineage hematopoiesis and adequate storage iron. There are no significant dysplastic changes, increase in blasts or atypical plasma cells infiltrates. Flow cytometry (FC-13-G3 57) shows no increase in blasts or atypical lymphoid populations. There are few multifocal atypical mast cell infiltrates, some associated with lymphoid aggregates.

Given the patient's clinical history and significantly elevated serum tryptase level (46.5 mg/L), marrow morphologic and immunohistochemical findings support the diagnosis of systemic mastocytosis.

Marrow involvement appears to be minimal with less than 5% of atypical mast cell seen, based on the biopsy sections with immunohistochemistry

There is no evidence of an associated clonal hematological non-mast cell lineage disease, based on the morphologic features in the current sample.

CBC red cell indices together with the findings on peripheral smear are consistent with thalassemia.


Bone marrow:

Examined are biopsy, aspirate smears, clot sections, and touch preparations.

The biopsy and clot sections show normocellular marrow with an estimated cellularity of 40-50%.

There is trilineage hematopoiesis with unremarkable maturation and distribution of the precursors.

Adequate megakaryocytes with unremarkable morphology are present. Vessels and bony trabeculae are unremarkable. No granulomas are seen.

There are few scattered loose lymphoid aggregates composed of small mature lymphocytes and admixed clusters of mast cells. Some of the mast cells have atypical (spindled) morphology and show degranulation of the cytoplasm.  Giemsa stain with functional control highlights some of the non-degranulated mast cells.

Reticulin stain shows no significant overall increase in reticulin fibrosis.

Immunohistochemical staining for CD3, CD20 and CD117, with functional controls, shows that the lymphocytes within the aggregates are composed of CD3+ T-cells and CD20+ B-cells. Increased numbers of CD117+ mast cells, both spindled and non-spindled, are present within aggregates, around vessels, and focally in linear arrays (overall <5% of marrow elements)

Aspirate smears and touch preparations show trilineage hematopoiesis with M:E ratio of approximately 2: 1.

Myelopoiesis is synchronous and complete to PMNs. There is no dysplasia or megaloblastic change of myeloid cells.  Blasts are not increased.  There is mild eosinophilia, but no significant basophilia or monocytosis.

Scattered mast cells are seen, some of which have irregular cytoplasmic granulation and spindled nuclei. Erythropoiesis is normoblastic without dysplasia.

Megakaryocytes have unremarkable morphology. Lymphocytes and plasma cells are not increased or atypical. Adequate storage iron is present on iron-stained smears with functional control. Ringed sideroblasts are not seen.

Peripheral blood:

RBCs are microcytic with occasional target cells seen There is a slight polychrollasl3. The platelet estimate is nornal with occasional large or giant platelets present There is no neutropenia, neutrophilia, left shift or Pl.1N dysplasia. No eosinophilia, basophilia, or monocytosis is present Lymphocytes are not increased or atypical. No blasts arc seen.


Bone marrow aspirate:

No increase in blasts or abnormal lymphoid population is detected. See comment.


The immunophenotypic findings do not support involvement of the marrow by acute leukemia or B or T-cell lymphoproliferative process. Correlation with the morphologic features is recommended (BM-13-263)
Corresponding surgical specimen #: BM-13-263


Received is a sample of bone marrow aspirate in heparin Viability is 95%. The smears show trilineage hematopoiesis with slightly increased numbers of spindled mast cells. Biopsy and clot sections show scattered lymphoid aggregates. The specimen is prepared using a direct lysis procedure. Immunophenotyping is performed using limited panel of monoclonal antibodies and multicolor gating.