July 2017 Case


Rob Bookstein, MD (Fellow), Mark Ewalt, MD (Molecular Pathology Attending), Wonwoo Shon, DO (Surgical Pathology Attending)

Overall Subject: Solid tumor profiling by NGS
Clinical History

A 70 year old man with a history of multiple back surgeries for spinal stenosis was found to have a right lower quadrant mass during follow-up CT scan. The outside imaging is not available, but reportedly showed a 9 x 8 x 7 cm circumscribed mass with features of a proteinaceous cyst, unrelated to appendix with no invasion of contiguous small bowel or colon. A CT-guided needle biopsy showed necrotic spindle cell tumor, and the patient underwent laparotomy for excision of the mass.

Immunohistochemical Studies
Study / Test (Clone)

DOG-1 (K9)

Positive (tumor cells)

Pancytokeratin (AE1/AE3)

Negative (tumor cells)

Actin, smooth muscle (Alpha am-1)

Negative (tumor cells)

Desmin (DE-R-11)

Negative (tumor cells)

S100 Polyclonal

Negative (tumor cells)

CD117 [C-Kit] QL

Positive (tumor cells)

ETS Transcription Regulator (EPR3864)

Negative (tumor cells)

ALK-1 Protein (5A4)

Negative (tumor cells)

Molecular Studies

KIT gene sequencing (Mayo Laboratories) - test not performed due to lack of viable tumor
CS-Focus GIST Panel by NGS (Cedars-Sinai PLM) - following macrodissection of small viable tumor area

  • Predominantly necrotic spindle cell neoplasm, consistent with subtotally necrotic gastrointestinal stromal tumor (GIST).
  • 7.3 x 6.3 x 5.8 cm
  • >5 mitoses per high power field
  • Tumor present at specimen surface
  • KIT V559A variant (allele fraction 14.8%) detected by CS-Focus GIST Panel
Have Questions or Need Help?

If you have questions or would like to learn more about the Anatomic and Clinical Pathology Residency Program at Cedars-Sinai, please call or send a message to Academic Program Coordinator, LeeTanya Marion-Murray.

Department of Pathology and Laboratory Medicine
8700 Beverly Blvd., Room 8709
Los Angeles, CA 90048-1804