Clinical Reasoning: A Dizzy Architect.

There is an increasing body of evidence describing an association between anti-Kelch-like protein 11 (KLHL11) encephalitis and various tumors such as seminoma. However, when the diagnosis of neoplasia is uncertain and the clinical syndrome resembles those caused by other etiologies, the possibility of anti-KLHL11 encephalitis may not be obvious during early clinical evaluations. We present the case of a 68-year-old man with clinical features of anti-KLHL11 encephalitis, in whom no clear signs of an active neoplasia could be found. However, a burnt-out germ cell tumor was suspected. This case highlights the importance of having a high clinical suspicion for anti-KLHL11 encephalitis in patients who exhibit symptoms and signs, even in the absence of an active tumor.