A case of IVIg responsive paraneoplastic SOX1 peripheral neuropathy in a male with breast carcinoma.

ABSTRACT

BACKGROUND AND AIMS: SOX1 antibodies are generally associated with small cell lung cancer and anti-Hu antibody overlap is common. This case demonstrates isolated anti-SOX1 antibodies with an uncommon tumor type, and relapse of a paraneoplastic syndrome with recurrence of tumor. METHODS: We describe a case of a 65-year-old male with a paraneoplastic peripheral neuropathy and anti-SOX1 antibody positivity in the context of a prior male breast Grade 2 ductal carcinoma, in remission at the time of the initial neurological presentation. RESULTS: Treatment response to intravenous immunoglobulin (IVIg) was demonstrated. After period of clinical stability on IVIg in the context of remission of breast carcinoma, the patient experienced a relapse of his neuropathy. This was associated with tumor recurrence and again responded to tumor excision, radiotherapy and IVIg. INTERPRETATION: Male breast carcinoma has not previously been associated with anti-SOX1 antibody positive paraneoplastic neuropathy.