<prompt> In a chronic smoker, a highly malignant aggressive and metastatic lung carcinoma is :Squamous cell CarcinomaAdenocarcinomaLarge cell carcinomaSmall cell Carcinoma  <response>: Cigarette smoking is most strongly associated with squamous Cell Ca and small cell Ca and less commonly associated with Adenocarcinoma.But small cell Ca is highly malignant Blood stream metastasis occurs early in the course of this Ca.So the answer is small cell carcinoma. Also RememberM.C Variety of lung Ca in India Squamous Cell CaM.C Variety in world AdenocarcinomaM.C Variety in young Patients AdenocarcinomaHistological Variety that cavitates Squamous cell CaM.C Histological variety to metastasi Small cell Ca Lung to lung metastasis is seen in Bronchoalveolar Ca a type of adeno CaClubbing least common in which Ca Small cell CaGynaecomastia is seen in which type of Ca large Cell CaThrombophlebitis is seen with which Ca AdenocarcinomaMost common site for metastasis from ca lung Adrenals Ref Robbins Basis 7e, p 760Lung Ca with worst prognosis Small cell Ca Variety most responsive to chemotherapy Small cell CaVariety most responsive to radiotherapy Small cell CaM.C Endocrine Gland to be involved by metastasis AdrenalVariety with best prognosis Squamous cell CAVariety that is central in location Squamous cell small cell CaVariety that is peripheral in location AdenocarcinomaMost common variety with Cushings syndrome Small cell CaMost common variety with Hypercalcemia dt PTH like substance Secretion Squamous cell Ca 