An ALK-positive lung adenocarcinoma with gastric and skin metastasis: a case report and literature review

Primary lung cancer with gastric metastasis is rare to see in the world, little is known about its characteristics. Here, we describe the first case of primary lung adenocarcinoma with gastric and skin metastases along with a review of literature to help clinical decision making. A 49-year-old woman admitted to our department for abdominal distension. The immunohistochemistry staining for the biopsy in the gastric fundus, back and lung showed positive for CK5/6, TTF-1, Napsin A and CK7, but negative for CK20, which strongly indicated all of them were homologous and might originate from lung adenocarcinoma. Chromosome mutation analysis presented an EML4-ALK fusion gene. Brain metastases occurred after 6 months with crizotinib treatment. More than two months later, intracranial lesions became more and larger as she persisted in taking crizotinib plus whole-brain radiotherapy (WBRT). Hence, alectinib was performed due to the continuous growth of brain lesions. When reexamined three months later, the craniocerebral lesions were significantly reduced and all tumor markers were up to normal level. This review comprised 42 published case reports in total. Generally, the average morbidity age was 62 years old, and male with smoking history were more prone to it. It could be found that squamous cell carcinoma (17/38) accounts for a high proportion of gastrointestinal metastases pathology, most of which were poorly differentiated. Surgical excision of the lesions was supposed to improve long-term prognosis, mitigate associated complications, decrease patients' pain, and enhance the quality of life. Gastric metastasis of lung cancer is apt to metastasize to the brain, and the prognosis is inferior. Crizotinib with preventive WBRT may be the optimal choice for NSCLC patients harboring ALK mutation in the initial treatment of gastric metastasis. However, If the lesion in the brain keep on going, timely replacement to alectinib is an appropriate choice.