WBR0246
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Gastrointestinal |
| Prompt | [[Prompt::A 62-year-old male complains of four months history of worsening abdominal pain. The pain is localized in the epigastric area and it is dull in nature, constant and progressively increasing in intensity independently from food intake or change in posture. Review of system is significant for several months history of increasing fatigue and weight loss. CT scan reveals a mass in the stomach. Endoscopy guided biopsy of the mass reveals extensive aggregation of spindle cells highly suspicious of gastrointestinal stromal tumor (GIST). Immunohistochemistry of which of the following is diagnostic of GIST?]] |
| Answer A | AnswerA::C-kit |
| Answer A Explanation | [[AnswerAExp::C-kit oncogene is associated with GIST. This is the correct answer. C kit gene encodes the human homolog of the proto-oncogene c-kit, also called CD117.]] |
| Answer B | AnswerB::Ret |
| Answer B Explanation | [[AnswerBExp::Ret oncogene is associated with MEN syndrome type IIa and IIb.]] |
| Answer C | AnswerC::Abl |
| Answer C Explanation | [[AnswerCExp::Abl oncogene is associated with CML.]] |
| Answer D | AnswerD::Ras |
| Answer D Explanation | [[AnswerDExp::Ras oncogene is associated with colon carcinoma.]] |
| Answer E | AnswerE::C-myc |
| Answer E Explanation | [[AnswerEExp::C-myc is associated with Burkitt's lymphoma.]] |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::The patient's symptoms of epigastric pain, fatigue, weight loss along with the CT finding of mass in the stomach points towards the diagnosis of malignancy. The spindle cells on pathology suggest the diagnosis of GIST which can be confirmed by positive immunohistochemistry for C-kit.
Educational objective: C-kit, also called CD 117, is associated with gastrointestinal stromal tumors (GIST). |
| Approved | Approved::No |
| Keyword | |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |