Miliary brain metastasis presenting with calcification in a patient with lung cancer: a case report

INTRODUCTION Miliary brain metastasis is an extremely rare form of brain metastasis which can present with atypical imaging findings. We report the case of a patient with miliary brain metastasis of lung cancer showing calcification in metastatic lesions. CASE PRESENTATION A 68-year-old Japanese woman was diagnosed with lung adenocarcinoma. Brain computed tomography revealed multiple small calcified lesions in both cerebral hemispheres. Mutation of the epidermal growth factor receptor gene (exon 21, L858R) in lung cancer cells was detected, and treatment with gefitinib was initiated. A partial response was observed; however, the patient was readmitted to our hospital because of regrowth of the primary lesion and complaints of nausea, headache, and difficulty walking. Brain magnetic resonance imaging revealed scattered tiny nodules enhanced by gadolinium. A diagnosis of leptomeningeal carcinomatosis was made on the basis of cerebrospinal fluid cytology. The patient's general status worsened, and she died 356 days after the day of first medical examination. Upon autopsy, the brain was found to be edematous and swollen. Lung carcinoma cells were diffusely disseminated on the meningeal surface. Metastatic foci of small nodular form, accompanied by calcifications, were also found in the brain parenchyma. We diagnosed miliary metastasis of lung carcinoma. CONCLUSIONS To the best of our knowledge, this is the third report of calcified miliary brain metastasis confirmed by autopsy. We describe calcified lesions that increased in size during the clinical course of nine months. Brain computed tomography findings that reveal multiple small calcified lesions in patients with malignancy should raise suspicion of miliary brain metastasis.