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Vol.57 No.7 contents | Japanese/English |
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- Case Report -
A Case of Occult Lung Cancer Detected Seven Years After the Appearance of Brain Metastases
Yasuhiro Nakashima1,4,5, Yuu Komatsu2, Reiko Taki2, Urara Sakurai3, Yuichi Ishikawa4, Katsuo Kojima11Department of Thoracic Surgery, 2Department of Respiratory Medicine, 3Department of Pathology, Musashino Red Cross Hospital, Japan, 4Department of Pathology, The Cancer Institute, Japanese Foundation for Cancer Research, Japan, 5Department of Thoracic Surgery, Tokyo Medical and Dental University, Japan
Background. Primary lung cancer may present as cancer of unknown primary more often than other cancers, but rarely does the occult period of lung cancer reach seven years. We herein report a rare case of primary lung cancer that had been latent from the time when the patient was diagnosed with a metastatic brain tumor. Case. A 60-year-old male was referred to our hospital in 2008 for paralysis symptoms. On an examination, multiple brain tumors were incidentally detected, and craniotomy was performed. The brain tumor was a poorly differentiated adenocarcinoma and was thought to be a metastatic lesion. A whole-body examination, including 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT), failed to detect the primary tumor, and the case was followed up as cancer of unknown primary. In 2015, a tumor measuring 54×30 mm was detected inside the bulla of the left upper lobe, with PET/CT revealing the high accumulation of 18F-FDG. Left upper lobectomy and partial resection of S6+ND2a-1 were performed. The histological diagnosis was pleomorphic carcinoma (T3N0M1b [BRA], pStage IV); the tumor mainly comprised malignant spindle cells with a papillary adenocarcinoma component. The adenocarcinoma component and brain lesion showed histological and immunohistochemical similarities, including immunoreactivity for TTF-1 and Napsin A. Therefore, it was inferred that the cancer in the brain was metastasis of lung cancer that had been occult cancer for seven years. Conclusion. Given that even modern, advanced imaging technologies have some limitations, careful follow-up should be a requirement in cases of cancer of unknown primary.
key words: Occult lung cancer, Cancer of unknown primary (CUP), Brain metastasis, Lung cancer
Received: June 27, 2017
Accepted: September 5, 2017
JJLC 57 (7): 838-842, 2017
