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7 August 2014 - Case of the Week #321

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Wayne State University
Karmanos Cancer Center
Detroit Medical Center

Presents the 11th Annual Conference

Contemporary Issues in Diagnostic Pathology

Program Director: Rouba Ali-Fehmi, MD

October 18, 2014
The Henry, Autograph Collection
Dearborn, Michigan (USA)

Brochure (link invalid)
Registration (link invalid)


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Case of the Week #321

Clinical History:
A 14 year old boy had a mass in the L5 vertebral body, with extension to the right paravertebral tissues, which was biopsied.

Xray images:

Bone scintigraphy


Micro images:

What is your diagnosis?

Primary Ewing sarcoma of lumbar vertebrae


Immunostains were obtained:







Bone scintigraphy shows a single hyperenhanced image at L5 with normal and symmetric uptake in hematopoietic areas.

Stains include CD99 (positive and strong in membrane), NSE (positive), PAS (positive in cytoplasmic granules), vimentin (negative) and desmin (negative). MyoD1 shows cytoplasmic staining, due to a cross reaction with an unknown antigen, which has been described in Ewing Sarcoma/PNET and neuroblastoma (Dabbs & Thompson: Diagnostic Immunohistochemistry 4th ed.).

Fewer than 10% of Ewing tumors arise in the vertebrae. In a study of 33 cases, the median age at diagnosis was 13 years, and 64% were male (Med Pediatr Oncol 2001;37:30). Six patients had metastatic disease and 10 had tumors 8 cm or larger. Primary sites were sacral (13), thoracic (10), lumbar (8), and cervical (2) vertebrae. Pain and neurologic deficits were common.

Histology shows sheets of small, round, uniform cells, 10-15 microns with scant clear cytoplasm, divided into irregular lobules by fibrous strands. The nuclei are round with indentations and small nucleoli. Homer-Wright rosettes (central fibrillary space) or pseudorosettes (cells arrange themselves around vessels) may be present (Bone-Ewing Sarcoma/PNET).

The differential diagnosis includes other small blue cell tumors: Most cases of Ewing sarcoma (85%) are due to t(11,22)(q24;q12), producing the EWS-FL1 fusion gene, a transactivator of the c-myc promoter.

Treatment is combination chemotherapy and local radiotherapy, with a 5 year survival of 48% to 70% (Eur J Cancer 2013;49:1314), comparable to this tumor at other sites. Most of the mortality is due to metastatic disease, which occurs in 30% (Case Rep Oncol Med 2012;2012:165289).

Nat Pernick, M.D., President
and Shivani Thakore, Associate Medical Editor
PathologyOutlines.com, Inc.
30100 Telegraph Road, Suite 408
Bingham Farms, Michigan (USA) 48025
Telephone: 248/646-0325
Email: NatPernick@Hotmail.com
Alternate email: NatPernick@gmail.com