Chronic airspace disease: Review of the causes and key computed tomography findings

Table 3 Clinical, laboratory and imaging findings, and prognosis/treatment of neoplastic causes of chronic airspace disease

Causes of chronic airspace disease/ General category	Clinical information	Laboratory findings	Imaging findings	Prognosis and treatment
Pulmonary adenocarcinoma in situ or minimally invasive/ Neoplastic	History of smoking is usually present		Predominantly GGO ≤ 3 cm with or without a small solid nodular component; Fried-egg sign; Mildly hypermetabolic on FDG/PET; Pseudocavitation may be present; Fissural or pleural retraction may be seen; Adenopathy and pleural effusion are uncommon at this stage	Surgical resection; Chemotherapy; Radiation treatment
Invasive adenocarcinoma of the lung/Neoplastic	History of smoking is usually present		Solid or subsolid and sometimes even ground glass nodule or mass; Consolidation with air-bronchogram, mimicking pneumonia has been mostly described in invasive mucinous adenocarcinoma subtype	Surgical resection; Chemotherapy; Radiation treatment
Pulmonary lymphoma/ Neoplastic	Primary (usually non-Hodgkin’s lymphoma) or secondary pulmonary lymphoma (can be Hodgkin’s or non-Hodgkin’s lymphoma)		Most common imaging finding: Mass or mass-like consolidation with or without cavitation	Surgery for localized diseas;e Chemotherapy; Radiation treatment; Good prognosis
PTLD/ Neoplastic	Occurs in 10% of solid organ transplant cases; Highest incidence in small bowel transplant; Can affect multiple organs		Pulmonary consolidation; Pulmonary nodules and masses which may cavitate	Treatment depends on location and extent of the disease; Treatment options: Reduction in immunosuppression; Resection of localized disease; Radiation treatment Chemotherapy
Pulmonary metastasis/ Neoplastic	Seen in adenocarcinoma of gastrointestinal tract and less commonly of breast and ovarian origin		Uncommon appearance of pulmonary metastasis appearing as persistent airspace opacity and consolidation; Due to lepidic growth of tumor cells along the intact alveolar walls	Treatment of the underlying cancer

FDG/PET: Fluorodeoxyglucose-positron emission tomography; GGO: Ground glass opacity; PTLD: Post-transplant lymphoproliferative disorder.