## **Core Concept**
Multiple myeloma is a type of plasma cell dyscrasia characterized by the proliferation of malignant plasma cells in the bone marrow. One of the complications of multiple myeloma is the production of abnormal proteins, including immunoglobulins and light chains, which can lead to the formation of amyloid fibrils. Amyloidosis associated with multiple myeloma is a form of primary amyloidosis.

## **Why the Correct Answer is Right**
The correct answer, **AL amyloidosis**, is associated with the deposition of light chain immunoglobulin fragments. In multiple myeloma, the malignant plasma cells can produce excess light chains (either kappa or lambda), which can then assemble into amyloid fibrils. These amyloid fibrils can deposit in various tissues, leading to organ dysfunction. AL amyloidosis is characterized by the presence of these light chain-derived amyloid fibrils.

## **Why Each Wrong Option is Incorrect**
- **Option A: AA amyloidosis** - This type of amyloidosis is associated with secondary amyloidosis, often seen in chronic inflammatory diseases, and is not directly related to multiple myeloma.
- **Option C: ATTR amyloidosis** - This form of amyloidosis involves the deposition of transthyretin-derived amyloid fibrils and is typically seen in familial amyloid polyneuropathy or age-related macular degeneration, not in multiple myeloma.
- **Option D: Aβ amyloidosis** - This type is associated with Alzheimer's disease, characterized by the deposition of amyloid-beta peptides, and is not related to multiple myeloma.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that patients with multiple myeloma are at risk for developing AL amyloidosis, which can manifest with symptoms such as nephrotic syndrome, heart failure, and neuropathy. The diagnosis of AL amyloidosis involves demonstrating the presence of light chain amyloid deposits in tissues, often through biopsy and specific immunohistochemical staining.

## **Correct Answer:** . **AL amyloidosis**