Parotid gland metastasis of lung adenocarcinoma identified on surveillance 18F-FDG PET/CT

Lung cancer metastasizing to salivary glands: Systematic review

ABSTRACTS

Metastasis to salivary glands from the secondary source outside the head and neck region is extremely rare and Carcinoma Lung is one of the rarest sources of distant spread to salivary glands. Owing to missed diagnosis and misdiagnosis, accurate identification of clinical and pathological aspects of these metastatic lesions remains a challenging task. Many studies regarding metastasis to the oral cavity have been already documented in the literature, but very little research work has been done to analyse the cases of lung cancer metastasis as the sole primary source, particularly to salivary glands. Thus this review was conducted to analyse the published cases of lung cancer metastasizing to salivary glands as the only primary source till date. An electronic search of the published literature was performed without publication year limitation in PubMed/ Medline, Scopus, Google Scholar, Web of Science, Science direct, Embase, and Research gate databases, using Mesh keywords like (Lung cancer', OR 'Lung carcinoma), AND (Metastasis OR Metastases), And (Salivary glands OR Parotid gland OR Submandibular gland OR Sublingual gland). We also searched all related journals manually. The reference list of all articles was also checked. Our research revealed 34 relevant papers between 1965-2022 with a total of 44 patients. The most prevalent diagnosed metastatic Lung cancer was Small cell lung cancer. Parotid was the most common gland involved in metastasis. 48% of patients died of metastasis with a mean survival time of 2.2 years. Salivary gland metastasis from Lung cancer is very rare and has a poor prognosis. More cases need to be published in order to raise awareness of these lesions and gain a better understanding of their characteristics.

Parotid metastases from primary lung cancer: Case series and systematic review of the features

Most parotid metastases have been reported to come from the head and neck; however, cases metastasized from the lung are extremely rare. Missed diagnoses and misdiagnoses occurred quite a few times. Thus, accurately identifying the clinical features of parotid metastasis of lung cancer is important. However, current studies about this issue are mostly case reports, and little is known about the detailed and systematic aspects. We reported three cases of parotid metastases from lung cancer and then systematically searched similar cases through “Pub-Med” and “Web of Science”. Finally, twenty-three patients were included in the study. Eighty-three percent of which were males, and 19 patients were over 50 years old. In all cases with smoking history mentioned, 93% were smokers. The predominant pathological type was small cell lung cancer (SCLC, 13 patients, 56%). Seventeen combined with other site metastasis, while more than half of which were brain metastases. The survival time ranged from 3months-17years, and as for SCLCs, it was only 3months-40months. It can be concluded that clinical features, such as sex, age, smoking history, pathological types, and metastasis patterns, could provide valuable evidence for diagnosis. The lung seems to be the most common primary site of parotid metastases except for head and neck tumors. The two circumstances, SCLC coexisting with Warthin’s tumor and parotid small cell carcinoma with lung metastasis, should be differentiated from parotid metastasis of lung cancer with caution For cases presented as SCLC, more aggressive strategies, such as chemotherapy with immunotherapy and maintenance therapy, may be more suitable. Due to the greater tendency of brain metastasis in such diseases, whole-brain radiation therapy, stereotactic radiosurgery or prophylactic cranial irradiation should be applied to corresponding patients in time. Additionally, lung cancer parotid metastases may be a marker of poor prognosis.