Cyst with a Twist! Diagnostic Dilemma

Obstructive hydrocephalus secondary to posterior cranial fossa space-occupying lesions is common, and treatment includes shunting or removal of the causative lesion. The list of posterior fossa space-occupying lesions is exhaustive and includes tumors, cysts, and tumor-like conditions. In the setting of cancer, the first differential is usually a metastatic deposit. However, unrelated pathologies could coexist and may be overlooked. We hereby describe an unusual case of a posterior fossa cystic, suspected metastatic lesion presenting with moderate to severe hydrocephalus in a patient with oral cavity cancer on chemotherapy, which turned out to be cysticercosis on excision, leading to a diagnostic dilemma; hence the adage "cyst with a twist"!