WBR0430
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Pathology |
| Sub Category | SubCategory::Hematology |
| Prompt | [[Prompt::A 78 year old patient presents to the physician’s office complaining of back pain that is not relieved by medications and fatigue of several weeks duration. Evaluation of the patient reveals anemia, elevated levels of serum calcium, and renal insufficiency. Peripheral smear of the patient’s blood shows characteristic “rouleaux formation”. The diagnosis of multiple myeloma is made. Which of the following markers is most commonly used for staging of multiple myeloma?]] |
| Answer A | AnswerA::BUN / Creatinine ratio |
| Answer A Explanation | AnswerAExp::BUN / Creatinine ratio is not useful for staging f multiple myeloma. It is helpful in determining the type of renal injury, as to whether it is pre-renal, instrinsic, or post-renal. |
| Answer B | AnswerB::β2 microglobulin and albumin levels |
| Answer B Explanation | AnswerBExp::β2 microglobulin and albumin levels are used in the ISS for multiple myeloma staging system. |
| Answer C | AnswerC::CA-125 level |
| Answer C Explanation | AnswerCExp::CA-125 levels are useful marker in follow-up of patients with ovarian cancer. However, CA-125 is not considered a diagnostic test of ovarian cancer and should not be used for diagnostic purposes. |
| Answer D | AnswerD::p53 and Retinoblastoma gene (Rb) activities |
| Answer D Explanation | AnswerDExp::p53 and Rb are tumor suppressor genes that are inactivated in many cancers. They are not useful for staging in multiple myeloma. |
| Answer E | AnswerE::Hemoglobin S levels |
| Answer E Explanation | AnswerEExp::Hemoglobin S levels, detected by hemoglobin electrophoresis, is diagnostic of sickle cell disease. |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::Multiple myeloma is a common hematologic cancer characterized by monoclonal gammopathy. It manifests as hypercalcemia, renal insufficiency, anemia, and lytic bone lesions; but occurrence of all 4 is not necessarily always present (mnemonic: CRAB – Calcium, Renal, Anemia, Bone). Rouleaux formation on peripheral smear is also a characteristic feature of multiple myeloma.
Multiple myeloma staging does not utilize the TNM system. Instead, the International Staging System (ISS) for multiple myeloma depends on levels of serum β2 microglobulin and albumin. Stage I: Serum β2 microglobulin < 3.5 mg/L and serum albumin ≥ 3.5 g/dL Stage II: Between stage I and III Stage III: Serum β2 microglobulin ≥ 5.5 mg/L Educational Objective: Multiple myeloma staging does not utilize the TNM system. Instead, the International Staging System (ISS) for multiple myeloma depends on levels of serum β2 microglobulin and albumin. Reference:
Mihou D, Katodritou E, Zervas K. Multiple myeloma staging based on the combination of beta-2-microglobulin and albumin: the role of albumin in the model. Hematology. 2007;12(6):527-31. |
| Approved | Approved::No |
| Keyword | WBRKeyword::beta, WBRKeyword::microglobulin, WBRKeyword::albumin, WBRKeyword::multiple, WBRKeyword::myeloma, WBRKeyword::rouleaux, WBRKeyword::formation, WBRKeyword::anemia, WBRKeyword::hypercalcemia, WBRKeyword::lytic, WBRKeyword::bone, WBRKeyword::renal, WBRKeyword::insufficiency, WBRKeyword::failure, WBRKeyword::gammopathy, WBRKeyword::monoclonal |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |