Fan-shaped ground-glass opacity (GGO) as a premonitory sign of pulmonary infarction: a case report.

Radiological findings of pulmonary infarction have been well characterized mainly in established infarction. However, the early course CT appearance of patients who develop pulmonary infarction has not yet been fully elucidated. A 50-year-old female with a history of postmenopausal hormone replacement therapy (HRT) presented with dry cough and high-resolution computed tomography (HRCT) findings of fan-shaped segmental ground-glass opacity (GGO) in the right lower lobe. As the parenchymal density in the GGO gradually enlarged over a period of 4 weeks in spite of antibiotic treatment, the patient was referred to our hospital on clinical suspicion of bronchioloalveolar cell carcinoma. However, the pathological findings of a transbronchial biopsy of the lesion were compatible with pulmonary infarction. After an endoscopic examination, the typical CT appearance of established pulmonary infarction was observed. Moreover, enhanced CT detected an intraluminal filling defect in the right lower lobe artery suggesting peripheral pulmonary emboli. Our case was a peripheral pulmonary infarction probably induced by HRT, and suggested that fan-shaped GGO may be a premonitory sign of pulmonary infarction.