This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Pathology
Pericyte formation occur in - 
Select and explain. 
A. Kaposi sarcoma, B. Glomus tumor, C. Hemangiopericytoma, D. Myopericytoma
C: Hemangiopericytoma
Answer: C: Hemangiopericytoma 
Explanation: Haemangiopericytoma is an uncommon tumor arising frompericytes. Pericytes are cells present external to the endothelialcells of capillaries and venules. This is a rare tumorthat can occur at any site and at any age and may vary insize from 1 to 8 cm.Microscopically, the tumor is composed of capillariessurrounded by spindle-shaped pericytes outside thevascular basement membrane forming whorledarrangement. These tumor cells may have a high mitoticrate and areas of necrosis. Silver impregnation stain (i.e.reticulin stain) is employed to confirm the presence ofpericytes outside the basement membrane of capillariesand to distinguish it from haemangioendothelioma Ref: Harsh Mohan - Textbook of Pathology, 6th Edition.page no.414