You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is Bronchoalveolar carcinoma variants are - and explain in detail?
Ref:Textbook of pathology (Harsh mohan) 6th edition,page no. 501 Bronchiolo-alveolar carcinoma is characterised by cuboidal to tall columnar and mucus-secreting epithelial cells growing along the existing alveoli and forming numerous papillary structures. Ultrastructurally, these tumour cells resemble Clara cells or less often type II pneumocytes.