Abstract
Background : Primary clear-cell lung carcinoma (PCCLC), a very rare lesion, is classified as a variation of squamous cell carcinoma, adenocarcinoma, or large cell carcinoma in General Rules for Clinical and Pathological Records of Lung Cancer. We report a case of PCCLC initially diagnosed as adenocarcinoma in bronchial brushing cytology and transbronchial lung biopsy (TBLB), and later as adenocarcinoma, mixed subtypes, predominantly clear-cell adenocarcinoma, in histopathological examination of the partially resected lung.
Case : An 80-year-old woman admitted for a continuous cough was found in chest x-ray imaging and computed tomography (CT) to have an upper right lung nodule 2.5 cm in diameter. TBLB and bronchial brushing cytology yielded a diagnosis of poorly differentiated adenocarcinoma. A section of resected cancer tissue 3.0×1.8 cm indicated adenocarcinoma with mixed subtypes, predominantly clear-cell adenocarcinoma.
Conclusions : Cytologically, many cancer cells showed naked nuclei but no evident clear-cell change, although resected lung tissue predominantly featured clear-cell adenocarcinoma. The absence of accumulated glycogen and lipid in cytoplasm suggested that one main cause of clear-cell change was cytoplasmic hydropic degeneration, which may make cell membranes susceptible to mechanical procedures, such as bronchoscopy and brushing cytology, yielding significant numbers of cancer cells with naked nuclei.
