A renal biopsy from a 56 year old woman with progressive renal failure for the past 3 years, shows glomerular and vascular deposition of pink amorphous material. It shows apple-green birefringence under polarized light after Congo red staining. These deposits are positive for lambda light chains. The person is most likely to suffer from

**Core Concept**
Amyloidosis is a group of diseases characterized by the deposition of amyloid fibrils, which are composed of various proteins, in various tissues and organs. In the kidney, amyloid deposition can lead to renal failure.

**Why the Correct Answer is Right**
The presence of pink amorphous material in the glomeruli and vessels, showing apple-green birefringence after Congo red staining, is pathognomonic for amyloidosis. The positive staining for lambda light chains suggests that this is a condition associated with monoclonal gammopathy, such as primary amyloidosis (AL amyloidosis). This condition is often seen in patients with plasma cell dyscrasias, such as multiple myeloma. The accumulation of lambda light chains in the glomeruli and vessels leads to renal failure.

**Why Each Wrong Option is Incorrect**
**Option A:** This option might be a distractor considering the association of amyloidosis with multiple myeloma, but the specific type of amyloidosis presented in the question is AL amyloidosis, not AA amyloidosis, which is associated with chronic infections or inflammatory conditions.
**Option B:** This option is incorrect because the question describes amyloidosis, not diabetic nephropathy, which is characterized by mesangial expansion and nodular glomerulosclerosis.
**Option C:** This option is incorrect because the question describes amyloidosis, not membranous nephropathy, which is characterized by subepithelial deposits.
**Option D:** This option is incorrect because the question describes amyloidosis, not IgA nephropathy, which is characterized by mesangial IgA deposits.

**Clinical Pearl / High-Yield Fact**
Amyloidosis can be diagnosed by the presence of amyloid fibrils in tissues, which show apple-green birefringence under polarized light after Congo red staining. This is a classic diagnostic feature of amyloidosis.

**Correct Answer:** D.

✓ Correct Answer: D. Multiple myeloma