Pulmonary Cryptococcosis Mimicking Lung Metastasis of Sigmoid Colon Cancer—Report of a Case—

Abstract

It is often difficult to differentiate between pulmonary cryptococcosis and primary or metastatic lung cancer. There are some cases in which diagnostic operation is considered for an abnormal lung mass. A 69-year-old man was diagnosed with sigmoid colon cancer and suspected liver metastasis. We performed laparoscopic sigmoid colectomy followed by partial liver resection, and the final diagnosis was sigmoid colon cancer (pT4a N0 M0 Stage IIb) with hepatic hemangioma. Adjuvant chemotherapy with oral capecitabine was performed for half a year. Two and a half years after the operation, a computed tomography (CT) showed a 7-mm solitary abnormal nodule in S2 of the right lung. F-18 fluorodeoxyglucose positron emission tomography (FDG-PET) showed accumulation of FDG in the lesion and lung metastasis was suspected. Thoracoscopic partial lung resection was performed and the final diagnosis was pulmonary cryptococcosis. No lung metastasis was found. Pulmonary cryptococcosis shows various imaging findings on CT and FDG-PET. If multiple lung nodules are observed and are regarded as unresectable even in this case, total chemotherapy might be selected for suspected multiple lung metastasis. Diagnostic examinations are important, for differentiating malignancies from non-malignant conditions, such as pulmonary cryptococcosis.