Coexistence of Lung Cancer and Neurocysticercosis: A Rare Case.

Lung cancer with brain metastasis has a high morbidity and mortality worldwide. Neurocysticercosis is a parasitic infection commonly found in regions with poor sanitation. We present a case with the coexistence of lung cancer and neurocysticercosis. A 57-year-old Caucasian female, with a history of secondhand smoke exposure, presented with a cough. Further evaluation revealed a lesion in the right upper lobe of the lung on a CT scan, a frontal lobe lesion on brain MRI, and hypermetabolic lymph nodes on a PET scan. Biopsies confirmed invasive moderately differentiated adenocarcinoma, indicating stage 4 lung cancer with a solitary brain metastasis. The patient underwent stereotactic radiosurgery for the brain lesion and subsequently received chemoradiation therapy. Upon completion of therapy, the patient showed improvement in both lung and brain lesions. Durvalumab maintenance therapy was initiated. However, a follow-up MRI of the brain revealed a new lesion in the right lateral ventricle. Stereotactic radiosurgery was performed to target this lesion. Five months later, a repeat MRI showed growth of the brain lesion. Given the atypical image finding, a biopsy of the right lateral ventricle lesion was performed, revealing an unexpected diagnosis of calcified parenchymal neurocysticercosis. The patient was referred to an infectious disease specialist who started the patient on dexamethasone without antiparasitic treatment. The co-occurrence of metastatic lung cancer to the brain and neurocysticercosis presents significant diagnostic and therapeutic complexities. Despite stereotactic radiosurgery, the patient's neurologic symptoms failed to improve, and subsequent radiographic assessments yielded inconclusive results. Consequently, a brain biopsy was performed, deviating from the usual practice in cancer management, revealing the unexpected presence of neurocysticercosis. This unforeseen diagnosis underscores the critical significance of contemplating alternative etiologies in patients exhibiting atypical clinical manifestations, particularly in regions devoid of prevalent parasitic infections. This case highlights the challenges in identifying and managing complex cases involving lung cancer and neurocysticercosis, where treatment decisions must balance the need for oncologic control and the management of parasitic infection.