Advanced lung adenocarcinoma detected by choroidal metastasis in a patient with amyopathic dermatomyositis: A case report

A 63‐year‐old Japanese man with amyopathic dermatomyositis treated with immunosuppressants became aware of distortion of his left visual field, and a metastatic choroidal tumor was suspected. His chest computed tomography (CT) showed a pulmonary nodule in the right upper lobe and mediastinal lymphadenopathy, and he was diagnosed with advanced lung adenocarcinoma with choroidal metastasis. Malignancies associated with dermatomyositis (DM) are often rapidly progressive and, in choroidal metastasis associated with lung cancer, a choroidal lesion is often diagnosed prior to lung cancer; therefore, CT performed at the time of diagnosis of choroidal metastasis may show lung cancer lesions. When ocular symptoms are observed in DM patients, metastatic malignancies should be suspected, and systemic examinations, such as positron emission tomography (PET)‐CT, should also be performed. Here, we present the first case of rapidly progressive lung adenocarcinoma and choroidal metastasis in a patient with ADM complicated with ILD undergoing immunosuppressant treatment, in whom the rapidness of initiation and progression of lung cancer was observed incidentally. Chest CT showed mediastinal lymphadenopathies (a), and contrast‐enhanced magnetic resonance imaging of the head showed left retinal thickening (white arrow) (b). Optical coherence tomography (OCT) showed mild serous retinal detachment in the macula (white arrows) (c), and fundoscopy evaluation showed white spots in the lower part of the left optic nerve papilla (white circle) (d).