In a chronic smoker, a highly malignant aggressive and metastatic lung carcinoma is :
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 Remember
M.C Variety of lung Ca in India → Squamous Cell Ca*
M.C Variety in world → Adenocarcinoma*
M.C Variety in young Patients → Adenocarcinoma*
Histological Variety that cavitates → Squamous cell Ca*
M.C Histological variety to metastasi → Small cell Ca* 
Lung to lung metastasis is seen in → Bronchoalveolar Ca (a type of adeno Ca)
Clubbing least common in which Ca → Small cell Ca*
Gynaecomastia is seen in which type of Ca → large Cell Ca*
Thrombophlebitis is seen with which Ca → Adenocarcinoma*
Most common site for metastasis from ca lung → Adrenals* (Ref Robbins Basis 7/e, p 760)
Lung Ca with worst prognosis → Small cell Ca* 
Variety most responsive to chemotherapy → Small cell Ca*
Variety most responsive to radiotherapy → Small cell Ca*
M.C Endocrine Gland to be involved by metastasis → Adrenal*
Variety with best prognosis → Squamous cell CA*
Variety that is central in location → Squamous cell & small cell Ca*
Variety that is peripheral in location → Adenocarcinoma*
Most common variety with Cushing's syndrome → Small cell Ca*
Most common variety with Hypercalcemia → d/t PTH like substance Secretion → Squamous cell Ca*
Squamous cell Carcinoma
Adenocarcinoma
Large cell carcinoma
Small cell Carcinoma