THORACIC AND RESPIRATORYDISORDERSSOLITARY PULMONARY NODULEThis is defined as an isolated round lesion <3 cm in diameter that is sur-
rounded by pulmonary parenchyma. Abnormalities >3 cm are termed masses
and are usually malignant. Cancer affects 10–70% of those with solitary pul-
monary nodules. Most benign lesions are infectious granulomas.
SYMPTOMS/EXAM
■ Patients are often asymptomatic but may present with cough, hemoptysis,
and dyspnea.
■ Older age and a history of cigarette smoking raise the suspicion of cancer.
■ Patients should be questioned about prior TB and histoplasmosis.
■ Physical examination of the lungs is frequently normal. However,
examination of the lymphatic system may demonstrate lymphadenopathy.
DIFFERENTIAL
Granuloma (old TB, histoplasmosis, foreign body reaction), bronchogenic carci-
noma, metastatic disease (usually >1), bronchial adenoma, round pneumonia
DIAGNOSIS
■ Solitary pulmonary nodules are usually discovered incidentally.
■ Comparison of serial CXRs: Theinitial step in determining the progres-
sion and extent of the nodule, stability of findings on CXR for 2 years is
considered a sign that the lesion is benign.
■ Chest CT: This offers improved estimation of nodule size, characteristics
(eg, pattern of calcification), and interval growth. Contrast enhancement
allows for the simultaneous evaluation of the mediastinum for lym-
phadenopathy.
■ PET scan: This may help provide staging information in the case of lung
cancer. The diagnostic accuracy of detecting mediastinal involvement
among patients with lung cancer is 65% by CT, 90% by PET, and >95%
using a combination of CT and PET.
TREATMENT
■ When the probability of cancer is low (age <35 years, nonsmokers, smooth
nodules with a diameter <1.5 cm), the lesion should be monitored with
serial high-resolution CT at 3-month intervals.
■ When the probability of cancer is high (age >35, smokers, spiculated nod-
ules with a diameter >2 cm), the lesion should be resected if preoperative
risk is acceptable and there are no other contraindications to surgery.
■ When the probability of cancer is intermediate, additional testing (PET,
transthoracic needle biopsy) may be warranted.
Lesions that ↑in size or
change in character are likely
malignant and should be
resected, assuming low
surgical risk and no evidence
of metastatic disease.