To illustrate a case of a woman with rhombencephalitis with antibodies to Kelch-like protein-11 (KLHL11) and a metastatic carcinoma.

KLHL11 encephalitis is an autoimmune paraneoplastic syndrome first described in 2019. The clinical presentation consists of a brainstem cerebellar syndrome with symptoms of hearing loss, diplopia, vertigo and ataxia. This entity has been mostly described in male patients with associated testicular seminomas. Few cases have been described in women. This is a case of a woman with a history of hysterectomy and oophorectomy with KLHL11 encephalitis and an associated aortocaval tumor. 

The patient was a 62-year-old woman that presented to clinic with a 9-month history of vertigo, progressive bilateral sensorineural hearing loss, diplopia, oscillopsia, ataxia and bilateral tremor. Her MRI brain obtained 8 months after symptom onset showed T2 hyperintense lesions in the inferior cerebellar hemispheres and right medial hippocampus with mild contrast enhancement in these areas. Cerebral spinal fluid analysis showed a lymphocytic pleocytosis, elevated protein, and negative infectious work-up. She completed 5 days of intravenous methylprednisolone and continued a steroid taper.  She noted mild to moderate improvement in tremors, gait, and diplopia after steroids. Her symptoms, however worsened as she tapered her steroid dose. Serum KLHL11 antibody levels were positive at a titer of 1:7680.  Computed tomography of the chest, abdomen and pelvis did not reveal any evidence of malignancy. However, whole body proton emission tomography/computed tomography (PET CT) revealed a large hypermetabolic aortocaval mass soft tissue mass. A biopsy of the mass showed pathology consistent with a metastatic carcinoma of gynecologic origin for which the patient is undergoing chemotherapy with plans for possible tumor debulking. 

This case highlights the importance of considering KLHL-11 encephalitis in female patients presenting with rhombencephalitis, and the need for adequate malignancy evaluation in this disorder.