In a smoker a tumor with central cavitation is found. This is most likely to be
|A||Squamous cell carcinoma|
|B||Small cell carcinoma|
a. Adenocarcinoma (ACA) of the lung is the most frequent histologic type and accounts for about 45% of all lung cancers.
b. ACA of the lung is derived from the mucus-producing cells of the bronchial epithelium.
c. Microscopic features consist of cuboidal to columnar cells with adequate to abundant pink or vacuolated cytoplasm and some evidence of gland formation.
d. Most of these tumors (75%) are peripherally located.
e. ACA of the lung tends to metastasize earlier than squamous cell carcinoma (SCCA) of the lung, and more frequently to the central nervous system (CNS).
f. Bronchoalveolar carcinoma (BAC) of the lung is a subcategory of ACA but can be at times a more indolent disease. It has the best prognosis overall of any kind of lung cancer because it is highly differentiated and spreads along alveolar walls.
g. BACmay present as a solitary nodule, multiple nodules, or diffuse parenchymal infiltrates.
h. SCCA of the lung occurs in about 30% of patients with lung cancer.
i. About two thirds of these tumors are centrally located and tend to expand against the bronchus, causing extrinsic compression.
j. These tumors are prone to undergo central necrosis and cavitation.
k. SCCA may be more readily detected on sputum cytology than ACA.