This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pathology
[{'content': 'Which of the following is the most characteristic ultrastructural feature of paraganglioma on electron microscopy? \nSelect and explain. \nA. Shrunken mitochondria, B. Large Golgi apparatus, C. Frequent mitoses, D. Dense core neuroendocrine granules', 'role': 'user'}, {'content': "Answer: D \nExplanation: Electron microscopy examination of paragangliomas show membrane bound electron dense neurosecretory granules in the cytoplasm of tumor cells. Ref: Head and Neck Surgical Pathology By Ben Z. Pilch, Page 68; Dail and Hammar's Pulmonary Pathology: Neoplastic Lung Disease By Joseph F. Tomashefski, Page 533; Salivary Gland Diseases: Surgical and Medical Management By Robe Lee Witt.", 'role': 'assistant'}]