P/Q and N-type Voltage-gated Calcium Channel Binding Antibodies Associated with Paraneoplastic Chorea and Mixed Invasive Ductal and Lobular Carcinoma of the Breasts in an Elderly Patient

Differential diagnosis of chorea (guidelines of the German Neurological Society)

INTRODUCTION

Choreiform movement disorders are characterized by involuntary, rapid, irregular, and unpredictable movements of the limbs, face, neck, and trunk. These movements often initially go unnoticed by the affected individuals and may blend together with seemingly intended, random motions. Choreiform movements can occur both at rest and during voluntary movements. They typically increase in intensity with stress and physical activity and essentially cease during deep sleep stages. In particularly in advanced stages of Huntington disease (HD), choreiform hyperkinesia occurs alongside with dystonic postures of the limbs or trunk before they typically decrease in intensity. The differential diagnosis of HD can be complex. Here, the authors aim to provide guidance for the diagnostic process. This guidance was prepared for the German Neurological Society (DGN) for German-speaking countries.

RECOMMENDATIONS

Hereditary (inherited) and non-hereditary (non-inherited) forms of chorea can be distinguished. Therefore, the family history is crucial. However, even in conditions with autosomal-dominant transmission such as HD, unremarkable family histories do not necessarily rule out a hereditary form (e.g., in cases of early deceased or unknown parents, uncertainties in familial relationships, as well as in offspring of parents with CAG repeats in the expandable range (27-35 CAG repeats) which may display expansions into the pathogenic range).

CONCLUSIONS

The differential diagnosis of chorea can be challenging. This guidance prepared for the German Neurological Society (DGN) reflects the state of the art as of 2023.

Voltage-Gated Calcium Channel Antibody-Induced Oropharyngeal Dysphagia Presenting as a Paraneoplastic Neurological Complication in Breast Cancer

Paraneoplastic neurologic syndromes (PNS) are a group of disorders characterized by an autoimmune response against the nervous system due to cross-reactivity between malignant and normal neural tissue. The most commonly associated malignancies include small cell lung cancer, ovarian cancer, breast cancer, and lymphoma. Multiple PNS have been reported including paraneoplastic cerebellar degeneration, retinopathy, sensorimotor peripheral neuropathy, encephalopathy, opsoclonus-myoclonus syndrome, and stiff-person syndrome.

We report a case of a 67-year-old woman with breast cancer who presented with a history of progressive oropharyngeal dysphagia as a paraneoplastic neurologic complication. She was diagnosed with invasive ductal carcinoma, nuclear grade 3 with moderate peritumoral lymphoid infiltrate. Hormone receptors were weakly positive for estrogen receptor (ER) (H score 15), weakly positive for progesterone receptor (PR) (H score 30), and negative for human epidermal growth factor receptor 2 (HER-2/NEU). The patient underwent a localized segmental mastectomy but declined any further adjuvant treatment. Three years after being diagnosed with invasive ductal carcinoma of the breast, she developed progressive oropharyngeal dysphagia that warranted percutaneous endoscopic gastrostomy (PEG) tube placement. Testing for onconeural antibodies was positive for voltage-gated calcium channel antibody. An extensive workup was negative for any alternative etiology that would explain her neurological symptoms. The patient declined further treatment and eventually succumbed to her illness.

Review of Hereditary and Acquired Rare Choreas

Background:

Movement disorders are often a prominent part of the phenotype of many neurologic rare diseases. In order to promote awareness and diagnosis of these rare diseases, the International Parkinson’s and Movement Disorders Society Rare Movement Disorders Study Group provides updates on rare movement disorders.

Methods:

In this narrative review, we discuss the differential diagnosis of the rare disorders that can cause chorea.

Results:

Although the most common causes of chorea are hereditary, it is critical to identify acquired or symptomatic choreas since these are potentially treatable conditions. Disorders of metabolism and mitochondrial cytopathies can also be associated with chorea.

Discussion:

The present review discusses clues to the diagnosis of chorea of various etiologies. Authors propose algorithms to help the clinician in the diagnosis of these rare disorders.

Non paraneoplastic immune-mediated calcium channel chorea

Antibodies to the N-type voltage-gated calcium channel have rarely been reported in association with chorea. Prior reported cases have been either paraneoplastic in nature or presented in the setting of other concurrent antibody elevations. Moreover, the identified studies showed only mild elevation of calcium channel antibodies. We present a case of chorea in association with an isolated serum elevation in N-type calcium channel antibodies and clinical improvement with intravenous immunoglobulin.