Solitary pulmonary capillary hemangioma presents as ground glass opacity on computed tomography indicating adenocarcinoma in situ/atypical adenomatous hyperplasia: A case report

Solitary pulmonary capillary hemangioma (SPCH) is a rare type of benign lung tumor, which must be distinguished from early lung cancer and precancerous lesions of the lung that manifest in a similar way upon imaging. The current study describes a case of SPCH and a review of the literature is performed. The patient was a 40-year-old Chinese woman who was referred to the Liaoning Cancer Hospital and Institute (Shenyang, China) in October, 2015 with a cough without obvious inducement. Computed tomography (CT) demonstrated pure ground glass opacity (GGO) in the right upper lung. Following systemic anti-inflammatory therapy over 6 months, the lesion did not exhibit any change on CT and was suspected to be an adenocarcinoma in situ (AIS) or atypical adenomatous hyperplasia (AAH). Video-assisted thoracic surgery wedge resection was subsequently performed. Frozen section diagnosis revealed a benign tumor without atypical epithelial cells. Subsequent to surgery, paraffin sections demonstrated that the tumor contained narrow alveolar cavities, thickened alveolar septa and a clear boundary separating it from healthy lung tissue. Furthermore, the proliferation lumens in the alveolar septa were lined with a single layer of flat cells. Immunohistochemical staining revealed that the flat cells were positive for cluster of differentiation CD31 and CD34, and negative for thyroid transcription factor-1 and cytokeratin. The proliferation of capillary vessels lead to the thickened alveolar septa and the tumor was diagnosed as SPCH. When imaging examination demonstrates a GGO in lung, SPCH must be considered in the differential diagnosis of AIS/AAH. As the prognosis of these lesions is entirely different, a pathological examination must be conducted to ensure a correct diagnosis.