The Hematologist

July-August 2018, Volume 15, Issue 4

Unusual Spindle Cell Lesion Involving Bone Marrow

Girish Venkataraman, MD Editor in Chief, ASH Image Bank; Medical Director, Immunohistochemistry; Associate Professor, Department of Pathology
The University of Chicago Medicine, Chicago, IL
John Kennedy Sydney Sir Philip, MD Hematopathology Fellow
University of Chicago, Chicago, IL

Published on: July 10, 2018

A 65-year-old man presented with syncope. Imaging showed mild hepatosplenomegaly. No skin lesions were observed. Laboratory evaluation detected pancytopenia with a complete blood count showing the following:

White blood cell count 4.3 × 103/μL
Hemoglobin 8.1 g/dL
Platelet count 35 × 103/μL

These results prompted a subsequent bone marrow biopsy. Peripheral blood smear showed rare abnormal circulating cells (Figure 1). Bone marrow core biopsy showed clusters of spindle cells adjacent to bony trabeculae (Figure 2) that were positive for CD117 (Figure 3). Scattered teardrop cells were also noted. Molecular testing by next-generation sequencing (NGS) detected diagnostic mutations.

Wright stain showing peripheral blood

Peripheral blood, Wright stain.


Stained core biopsy of bone marrow showing hematoxylin and eosin

Hematoxylin and eosin–stained core biopsy of bone marrow.


Immunohistochemical stain on core biopsy showing CD117

CD117 immunohistochemical stain on core biopsy.

 

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