Infratentorial single cystic metastatic lesion: a radiological diagnostic dilemma

Non-small cell carcinoma (NSCC) of lung is an unusual cause of single cystic metastatic infratentorial lesion. Infratentorial single cystic lesion is very unusual for metastatic brain varieties though lung carcinoma is the most frequent source of brain metastasis. We reported an uncommon case of a 64 -year - old gentleman presented with cerebellar ataxia. His MRI brain revealed single cystic infratentorial rim enhancing lesion. CT guided biopsy and histopathology favored the diagnosis of metastatic NSCC of lung. According to the radiological findings, there was an ambiguity in differentiating primary from metastatic posterior fossa neoplasm. Therefore, it is pivotal to consider broad differential diagnosis along with histopathological confirmation in identifying single cystic infratentorial brain lesion.