[Bronchial glomus tumor: report of 2 cases and review of the literature].

OBJECTIVE

Glomus tumor is a small, predominantly benign tumor, and typically occurs in the soft tissues, rarely in bronchus. The aim of this study was to discuss the clinical manifestation, histology, diagnosis and differential diagnosis of bronchial glomus tumor.

METHODS

We studied the histopathological and immunohistochemical results of 2 cases with bronchial glomus tumor. One case was diagnosed by bronchoscopic biopsy, and another by surgery. We searched Wanfang, VIP, CNKI and PubMed database for related articles with key word "bronchial glomus tumor" both in English and in Chinese for literature review.

RESULTS

Fiberoptic bronchoscopy demonstrated a bronchial neoplasm in both 2 cases. For Case one, the tumor was pink under fluorescence bronchoscopy, and was histologically composed of groups of nuclear-irregular round cells in interstices, with pale staining plasma and unclear boundary. Immunohistochemically, cytokeratin (CK) was negative, while vimentin and CD34 vascular endothelial cell were positive, smooth muscle actin (SMA) weakly positive, and Synaptophysin partially positive in tumor cells. These results led to the diagnosis of bronchial glomus tumor of right upper lobe bronchus. The tumor of Case two was histologically from the right main bronchus mesechyma, and it invaded into submucosa, but not involving the tracheal cartilage. Histological examination showed groups of medium sized tumor cells with round nuclei, and abundance of interstitial vasculature. No cellular atypia or mitoses were observed. Immunohistochemical staining demonstrated positive reactivity for vimentin, SMA and CD99. Pathological diagnosis was right main bronchus glomus tumor (malignant potential indeterminacy). We identified 16 studies from databases, of which 15 studies including 15 cases (12 males, 3 females) were applicable. Age of onset ranged from 20 to 79 years. The lesion was in the left main bronchus in 8 cases, the right main broncus in 2, the right middle lobe bronchus in 3, and the right upper lobe bronchus in 2 cases. The tumor size ranged from 0.7 to 6.5 cm. Cough, dyspnea with or without fever were observed in 7 patients. Seven cases had blood in phlegm, and 4 patients showed pulmonary atelectasis. All cases showed negative CK staining and positive SMA staining.

CONCLUSION

Bronchial glomus tumor usually lacks clinical manifestations, and is often misdiagnosed as bronchial asthma. It can be classified as solid glomus tumor, ball hemangioma, ball vascular leiomyoma by histopathology. Glomus tumors show positive immunohistochemical stainings for vimentin and smooth muscle actin (SMA), and are usually negative for cytokeratin (CK) and epithelial markers. Clinical differential diagnoses such as sclerosing hemangioma, hemangiopericytoma, carcinoid tumor and epithelial tumor should be considered.