Paraneoplastic Cerebellar Degeneration Associated with Breast Cancer: A Case Report and a Narrative Review

Abstract

Paraneoplastic neurological syndromes (PNSs) are an uncommon complication of cancer, affecting nearby 1/10,000 subjects with a tumour. PNSs can involve all the central and peripheral nervous systems, the muscular system, and the neuromuscular junction, causing extremely variable symptomatology. The diagnosis of the paraneoplastic disease usually precedes the clinical manifestations of cancer, making an immediate recognition of the pathology crucial to obtain a better prognosis. PNSs are autoimmune diseases caused by the expression of common antigens by the tumour and the nervous system. Specific antibodies can help clinicians diagnose them, but unfortunately, they are not always detectable. Immunosuppressive therapy and the treatment of cancer are the cornerstones of therapy for PNSs. This paper reports a case of PNSs associated with breast tumours and focuses on the most common paraneoplastic neurological syndromes. We report a case of a young female with a clinical syndrome of the occurrence of rigidity in the right lower limb with postural instability with walking supported and diplopia, with a final diagnosis of paraneoplastic cerebellar degeneration and seronegative rigid human syndrome associated with infiltrating ductal carcinoma of the breast.

Keywords: antibodies; autoimmunity; malignancy; paraneoplastic neurological syndromes.

Figure 1

Pathogenetic cross reactions in pathogenesis of PNSs (paraneoplastic neurological syndromes). Common antigens of the tumour and the nervous system are presented to the immune system through tumour cells’ necrosis which leads to antigens’ release and phagocytation and presentation by APCs (Antigen-Presenting Cells), which migrate towards the lymph node area (illustrated in the figure above by the green dotted line). In nodes, APCs present tumour cells’ antigens to CD8+ cytotoxic T cells and CD4+ t-helper T + cells (thus leading to plasma cells activation and antibody production). Due to antigens’ cross-reactivity, this cross reaction induces the production of CD8+ cytotoxic T cells and autoantibodies that target the nervous system (both peripheral nervous system and central nervous system. APCs (Antigen-Presenting Cells); TCAs (Tumour Cell Antigens); MHC-I (Major Histocompatibility Complex—class I); MHC-II (Major Histocompatibility Complex—class II); TCR (T-Cells Receptor).