Pulmonary sclerosing pneumocytoma mimicking lung cancer: Case report and review of the literature

Abstract

Pulmonary sclerosing pneumocytoma (PSP) is a rare benign neoplasm that predominantly affects middle-aged Asian women. PSP is often asymptomatic and demonstrates a solitary pulmonary nodule on radiologic examination. We report a case of PSP initially misdiagnosed as lung cancer because of strong (18)F-fluorodeoxyglucose (FDG) uptake revealed by (18)F-FDG positron emission tomography-computed tomography scan. After surgery, pathology revealed that the tumor cells were immunopositive for epithelial membrane antigen and thyroid transcription factor-1. The patient has been followed up without complication or recurrence.

Keywords: Positron emission tomography; pulmonary sclerosing hemangioma; solitary pulmonary nodule.

Figure 1

(a) Computed tomography (CT) obtained at another hospital during percutaneous needle biopsy shows a 1.5 cm round nodule in the left lower lobe, adjacent to the left cardiac border. (b) CT performed six months later revealed a slightly increased nodule diameter of 2 cm. (c) The nodule was solitary, well‐circumscribed, and round‐shaped in the anteromediobasal segment of the left lower lobe. (d) ¹⁸F‐ fluorodeoxyglucose (FDG) positron emission tomography‐CT revealed high FDG uptake (maximum standardized uptake value = 3.9) at the nodule without regional or distant metastasis.

Figure 2

After surgical resection, a solid, yellow mass about 2.5 cm in size was separated by normal lung parenchyma.

Figure 3

(a) A well‐demarcated solid mass was easily separated by normal lung parenchyma (hematoxylin and eosin [H&E], × 20). (b) The hemorrhagic mass is situated in the sub‐bronchial area (H&E, × 40). (c) Focal sclerotic change was shown within the tumor (H&E, × 100). (d) The tumor was composed of monotonous, round tumor cells covered by hyperchromatic spindle cells (H&E, × 400). (e) Immunohistochemical staining detected epithelial membrane antigen in the surface of the tumor cells, but not in the round cells (× 100). (f) Thyroid transcription factor‐1 was detected in both the surface tumor cells and the round cells (× 100).