Clinical History:

A 49-year-old man had a 100 pack/year history of smoking. He had a chronic cough, but recently he noted some blood-streaked sputum along with chest pain. A chest CT scan was performed. After clinical work-up, the tumor that was found was not amenable to resection and radiation therapy was initiated.

There are large to bizarre neoplastic cells. The centers of some of the tumor masses demonstrate keratinization (cells with eosinophilic cytoplasm). The concentric arrangement of the keratin leads to the descriptive phrase "keratin pearls". There is also necrotic (amorphous eosinophilic) tissue. The larger the mass, the more likely that the tumor will outgrow its blood supply and develop areas of necrosis, often centrally in the tumor mass(es).

Questions:

1. What caused this cancer?

Smoking is a major risk factor for lung cancer. The two lung cancer types most strongly associated with smoking are squamous cell carcinoma and small cell anaplastic ("oat cell") carcinoma.

2. Where would this tumor metasatasize first?

Hilar lymph nodes. It could also later spread to the pleura (seeding) and chest wall locally (invasion). Distant metastases could include sites such as the opposite lung, adrenal, bone marrow, and brain.

3. What methods are available for diagnosis of this neoplasm?

Radiographic procedures can be used initially to determine if a mass is present and, if so, where to sample the tissue. Sputum cytology, bronchoalveolar lavage (BAL), fine needle aspiration (FNA) cytology, transbronchial biopsy, and open lung biopsy (in increasing order of invasiveness) can be employed for histologic diagnosis. The sputum cytology is the cheapest and easiest to obtain but may not have a high sensitivity. FNA can be directed under radiographic guidance to the mass. BAL is more sensitive for diagnosis of infections than for neoplasms.