Rapidly progressive cerebellar syndrome as a manifestation of paraneoplastic brain damage. A case report

Abstract

Introduction. Rapidly progressive cerebellar syndrome (RPCS), previously referred to as “subacute cerebellar degeneration” or “paraneoplastic cerebellar degeneration”, is an autoimmune disorder, wich in the most cases is associated with a malignancy located outside the nervous system. RPCS is classified as one of the the paraneoplastic neurological syndromes and manifests in the early, often preclinical stages of oncopathology. Its diagnosis is difficult, but is necessary, since it can become a starting point for further screening for cancer. The article provides a clinical description of a 40-year-old patient with subacute development of hemiataxia and subsequent rapid progression of bilateral cerebellar deficiency associated with brainstem signs. The example of this case shows how difficult the diagnostic path is, since only the use of positron emission tomography and subsequent examination of a biopsy of the lesion in this patient made it possible to identify metastasis of poorly differentiated breast carcinoma in the axillary lymph node. The tumor itself was not found in the mammary gland. Since paraneoplastic antibodies were not detected in the patient’s blood and cerebrospinal fluid, a diagnosis of “probable” (not “definite”) RPCS was diagnosed in accordance with the diagnostic criteria proposed by the panel of experts in 2021. The treatment of cancer stopped progression of neurological deficit in the patient, but she remained severely disabled. Discussion. The approaches to the examination of patients with RPCS are discussed. Clinical assessment, neuronal antibodies testing and a targeted screening for cancer should be performed. Brief information is provided on the use of the PNS-Care scale in the diagnosis of paraneoplastic neurological syndromes. Conclusion. The presented case demonstrates the difficulties of diagnosing the RPCS and the associated cancer. The “definite” diagnosis of rapidly progressive cerebellar syndrome requires the presence of high or moderate risk antibodies and cancer that is consistent with the syndrome’s phenotype.

Keywords

• rapidly progressive cerebellar syndrome
• subacute cerebellar degeneration
• paraneoplastic neurological syndromes
• antineuronal antibodies.