This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urinary tract, Subject name: Pathology
The cresecent forming forming glomerulonephritis is - 
Select and explain. 
A. RPGN, B. Acute GN, C. Membranous GN, D. Membrano proliferative GN
A: RPGN
Answer: A: RPGN 
Explanation: Distinctive lesions of proliferation are called crescents owing to their shape as they fill Bowman's space. Crescents are formed both by the proliferation of parietal cells and by the migration of monocytes/macrophages into Bowman's space. The glomeruli show cellular proliferation outside the capillary loops, sometimes in association with segmental capillary necrosis, breaks in GBM, and deposition of fibrin in Bowman's space. Ref:- Robbins book of basic pathology 10th Ed. pg 532.