Objective: .

Background: Paraneoplastic syndromes encompass a range of neurologic disorders triggered by an immune response to neoplasms, mediated by antibodies or cellular mechanisms. Paraneoplastic chorea is rare, with only one reported case in the literature. We report a case of progressive chorea due to voltage-gated calcium antibodies in the setting of ductal carcinoma in situ.

Method: A 72-year-old female presented to the movement disorder clinic with abnormal movements involving the hands, legs, and mouth that began in 2021. Clinical examination revealed moderate-to-severe chorea in the mouth, upper and lower limbs, and moderate rigidity. Mild bradykinesia in both hands and difficulty performing fist–hand–palm sequences were noted. The patient was also unable to sustain tongue protrusion for 10 seconds. Gait analysis demonstrated a wide-based, unsteady pattern without shuffling.

Diagnostic workup included a normal brain MRI, positive ANA, positive double-stranded DNA antibodies, and a negative Huntington’s test. The patient had no anti-dopaminergic exposure and her CT Chest, abdomen, pelvis was negative for any malignancy.  We proceeded with mammogram which did show a suspicious lesion.  The patient was managed with tetrabenazine 37.5 mg twice daily, which did not improve her symptoms. Subsequently, a lumpectomy was performed with biopsy confirming ductal carcinoma and a paraneoplastic panel showed mild positivity for voltage-gated calcium channel antibodies (0.09). On subsequent follow up, patient exhibited marked improvement in her Chorea, specifically in her arms; although, complete improvement was not noted on initial follow up. We attributed the chorea to a paraneoplastic process associated with her malignancy and decided to proceed with 5 days of IVIG treatment.

Results: .

Conclusion: Paraneoplastic chorea is thought to arise from immune-mediated disruption of neuronal function. Voltage-gated calcium channel antibodies are implicated in several paraneoplastic neurologic syndromes, often linked to malignancies such as breast cancer. This case exhibited a unique constellation of Chorea that was found to be secondary to a paraneoplastic process secondary to breast cancer, which has been scarcely reported in the past. This case also illustrated clinical improvement of Chorea after removal of the tumor, which further corroborates its role in the initial chorea. Response to IVIG treatment is still to be assessed.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/dance-by-mammary-a-case-of-paraneoplastic-chorea-associated-with-ductal-carcinoma-in-situ/