A 62-year-old man with hemoptysis and a long smoking history has hypercalcemia and a coin lesion on chest imaging. The most likely diagnosis is which type of lung cancer?

A 62-year-old man with hemoptysis and a long smoking history has hypercalcemia and a coin lesion on chest imaging. The most likely diagnosis is which type of lung cancer?

• A. Adenocarcinoma
• B. Squamous cell carcinoma
• C. Small cell carcinoma
• D. Bronchioloalveolar carcinoma

Answer: (C)

Hypercalcemia with a lung tumor in a smoker points most strongly to squamous cell carcinoma because squamous cells frequently produce PTH-related peptide (PTHrP), causing a paraneoplastic hypercalcemia. A solitary pulmonary nodule in an older, heavy smoker fits a malignant lesion, and the hypercalcemia helps differentiate among common histologies. Adenocarcinoma is the most common lung cancer overall and tends to occur peripherally, especially in nonsmokers, and it’s not typically linked to hypercalcemia. Bronchioloalveolar carcinoma (a subtype of adenocarcinoma) often presents as a pneumonia-like opacity or multifocal nodules rather than a solitary central lesion and also doesn’t classically cause hypercalcemia. Small cell carcinoma is strongly associated with paraneoplastic syndromes too, but the typical paraneoplastic effects are SIADH (hyponatremia) or ectopic ACTH production, not hypercalcemia.

Hypercalcemia with a lung tumor in a smoker points most strongly to squamous cell carcinoma because squamous cells frequently produce PTH-related peptide (PTHrP), causing a paraneoplastic hypercalcemia. A solitary pulmonary nodule in an older, heavy smoker fits a malignant lesion, and the hypercalcemia helps differentiate among common histologies.

Adenocarcinoma is the most common lung cancer overall and tends to occur peripherally, especially in nonsmokers, and it’s not typically linked to hypercalcemia. Bronchioloalveolar carcinoma (a subtype of adenocarcinoma) often presents as a pneumonia-like opacity or multifocal nodules rather than a solitary central lesion and also doesn’t classically cause hypercalcemia. Small cell carcinoma is strongly associated with paraneoplastic syndromes too, but the typical paraneoplastic effects are SIADH (hyponatremia) or ectopic ACTH production, not hypercalcemia.