**Question:** Bone scan in multiple myeloma shows –

A. Increased uptake in bone lesions
B. Reduced uptake in areas of active bone remodeling
C. Decreased uptake in areas of bone marrow infiltration
D. Normal uptake throughout the skeleton

**Core Concept:** Bone scan in multiple myeloma is a nuclear medicine imaging technique used to detect bone involvement and assess bone marrow function. In this condition, plasma cells (derived from B-cells) infiltrate bone marrow and produce monoclonal proteins (M-proteins), leading to abnormal bone remodeling and increased risk of bone lesions.

**Why the Correct Answer is Right:** A bone scan in multiple myeloma typically demonstrates increased uptake in areas of active bone lesions, which are characteristic of the disease. This reflects the increased bone remodeling activity due to plasma cell infiltration and abnormal bone turnover.

**Why Each Wrong Option is Incorrect:**

B. Reduced uptake in areas of active bone remodeling is incorrect because, in multiple myeloma, there is increased bone remodeling due to plasma cell infiltration and abnormal bone turnover.

C. Decreased uptake in areas of bone marrow infiltration is incorrect because, as mentioned earlier, multiple myeloma leads to increased bone remodeling and active bone lesions, not decreased uptake.

D. Normal uptake throughout the skeleton is incorrect because multiple myeloma causes abnormal bone turnover and increased risk of bone lesions. A normal bone scan would not reflect the disease process.

**Clinical Pearl:** A bone scan in multiple myeloma is essential for assessing bone involvement, monitoring response to therapy, and detecting relapse. It helps in determining the extent of bone marrow infiltration and assessing the overall disease burden.

**Correct Answer:** A. Increased uptake in areas of active bone lesions

In multiple myeloma, a bone scan reveals increased uptake in areas of active bone lesions, reflecting the increased bone remodeling and abnormal bone turnover caused by plasma cell infiltration and monoclonal protein production. This information is crucial for diagnosing, staging, and monitoring treatment response in patients with multiple myeloma.