OC is considered as the most lethal gynecologic malignancy and ovarian cancer cells can directly attack the surrounding pelvis organs such as bladder (17%) and colon. Besides, ovarian cancer cells can also arrive at peritoneum and omentum (86%), intestinal (50%) and spleen (20%), through peritoneal fluid transportation [13]. The common metastatic routes are lymphatic metastasis and direct invasion, while the hematogenous metastasis only accounts for 16% and the hematogenous metastatic sites are always liver, lung and pleura [13]. Although the end-stage OC can metastasize to lung, the endobronchial metastasis is extremely rare and there is no study on this disease in China, before our research. The intervals between primary OC and endobronchial metastasis are always long with the mean interval as 65.3 months, and the maximum time was up to 21 years [10]. The development of endobronchial metastasis from primary OC is a slow progress and the media survival time of 10 cases before 2018 ranged from 6 to 24 months [14]. Compared with metastatic chest tumors, the endobronchial metastasis from primary OC often showed good prognosis [15].
The potential mechanisms of endobronchial metastasis from primary OC were complicated and that may include mediastinal lymph nodes metastasis, hematogenous metastasis, lymphatic metastasis and parenchymal metastasis [7, 9, 16]. In addition, the routine imaging examination can’t clearly distinguish endobronchial metastasis from primary bronchial tumors. Clinical manifestations of endobronchial metastasis are dyspnea, dry cough, hemoptysis, anhelation and hoarsness. However, 52% ~ 62.5% patients showed no respiratory symptoms [16]. Stenosis of airway and thickening vessel walls observed by chest CT, may be due to diseases from intratracheal site, tracheal mucosa and airway surroundings. Furthermore, only 50% endobronchial diseases can be found by chest CT. Therefore, physician scientists always misdiagnose the endobronchial metastasis from primary OC as primary bronchial tumors [3].
Flexible bronchoscopy is a direct detection method for endobronchial metastasis and its characteristics vary widely, including benllones combined with necrosis and nodular masses. However, flexible bronchoscopy can’t differentiate between benign tumor, primary lung cancer and tumor metastasis. Therefore, pathological and immunohistochemistry assay are necessary to identify the tumor origins. According to the metastatic modes, the tumors metastasis to airways can be divided into four types, Ⅰ type, direct metastatic tumor; Ⅱ type, airway tumors invaded from pulmonary solid lesions; Ⅲ type, airway tumors invaded from lymph nodes of mediastinum and hilum; Ⅳ type, airway tumors invaded from peripheral lesions [17]. Ⅱ and Ⅲ types are in the majority. Dhillon et al reported a unique endobronchial metastasis combined with airway calcification [11]. Unfortunately, the clinical manifestations of airway calcification and broncholithiasis are very similar, which may result in misdiagnose. Ayub et al described an unusual endobronchial metastasis combined with aspergillosis and the patient showed hemoptysis [12].
The treatments for endobronchial metastasis, such as resection, chemotherapy and radiotherapy, depends on multiple aspects, like patients’ status, age, and tumor size, location and others. Choi et al firstly reported that needle electrical knife was applied to remove the bronchial metastasis focuses and this method effectively relieved patients’ dyspnea and hemoptysis [8]. The endobronchial intervention such as stent, local radiotherapy and photodynamic therapy, may be efficient methods for alleviating patients’ dyspnea, hemoptysis and stenosis induced by endobronchial metastasis. However, endobronchial intervention showed little effect on patients with submucosa metastasis. Some research indicated that atomizing chemotherapy might be an ideal method for patients with submucosa metastasis, for the long detention and high drug concentration in lesions, and it was estimated that the drug concentration in tumor tissues was almost 5 ~ 15 times higher than that in normal lung tissues [16]. By now, some novel therapeutic regimens are still necessary for the treatment of endobronchial metastasis.
In conclusion, endobronchial metastasis from primary OC is extremely rare. The latent period of this disease was long and clinical manifestation are always hiding. Flexible bronchoscopy combined with imaging and immunohistochemistry tests are efficient diagnostic approach. Endobronchial intervention, radiotherapy and chemotherapy could be taken for the patients’ treatment. The individual endobronchial metastasis can be acquired good prognosis after active treatment, while the prognosis of patients with multiple metastasis is usually poor.