This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Misc. (W.B.C), Subject name: Pathology
An elderly male presented with history of intractable diarrhea. His bone marrow and renal biopsy as shown below. Which of the following is the most appropriate diagnosis? 
Select and explain. 
A. Leishmaniasis, B. Multiple myeloma, C. Lymphoma, D. Urate nephropathy
B: Multiple myeloma
Answer: B: Multiple myeloma 
Explanation: Ans. (b) Multiple myeloma(Ref: R 9/ 595)Key to the image: 1 - Increase in plasma cells in marrow, 2 - Kidney biopsy with pink deposits in glomerulus, 3 - Fibrils in electron microscope. So the diagnosis is Multiple myeloma, probably AL amyloidosis of kidney