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': 'Bilateral breast ca is - \nSelect and explain. \nA. Scirrhous ca, B. Medullary ca, C. Lobular ca, D. Ductal ca', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Lobular carcinoma (invasive) is frequently bilateral.\nLobular carcinoma in situ in 20-40% cases are bilateral.\nFeatures of invasive lobular carcinoma of breast are\xa0:\nHistologic hallmark\xa0: pattern of single infiltrating tumor cells often only one cell in width or in loose clusters or sheets.\nSignet ring cells\xa0common\nLobular carcinoma have a different pattern of metastasis compared to other breast cancers. metastases to the peritoneum, retroperitoneum, leptomeninges (Carcinomatous meningitis), the git, and the ovaries & uterus are frequently observed, these carcinomas are less likely to metastasize to lung and pleura.', 'role': 'assistant'}]