Clear cell tumor of the lung: a case report and literature review

Abstract

Clear cell tumor of the lung is a rare and benign pulmonary tumor; only sporadic cases have been reported. Here, we report the case of a 38-year-old man with recurrent cough, blood-streaked sputum and left chest pain. A chest computed tomography scan showed a round, homogeneous pulmonary mass in the left lower lobe, which exhibited intense heterogeneous enhancement in the arterial phase and homogeneous in the delay phase after injecting a contrast agent. The patient underwent a fine-needle aspiration biopsy and was diagnosed as having a benign clear cell tumor of the lung. The clinical presentation and radiographic investigation of this tumor are summarized in this paper to recognize this rare disease. Interestingly, we found some differences with previously reported cases.

Figure 1

Chest computed tomography findings of the tumor. (A) Chest plain computed tomography scan shows a solitary, rounded, smooth-surfaced, homogenous density mass of approximately 3.4 cm in diameter in the left lower lobe (S6). (B) The contrast-enhanced arterial phase shows intense heterogeneous enhancement measuring 67.2 to 128.0 Hounsfield units. (C) The contrast-enhanced delay phase shows an isodense nodule measuring 66.3 Hounsfield units.

Figure 2

Microscopic and immunohistochemistry findings. (A) Histopathological examination shows diffuse growth of rounded or oval cells with abundant clear cytoplasm, distinctive cell borders, and thin-walled blood vessels (hematoxylin and eosin, ×200. (B) Most neoplastic clear cells have intracytoplasmic periodic acid-Schiff-positive glycogen granules (streptavidin-perosidase, ×200. (C) Many tumor cells show cytoplasmic staining for HMB-45 (streptavidin-perosidase, ×200).