Isolated Myelopathy in Occult Breast Carcinoma with Negative Paraneoplastic Antibodies: A Case Report of a Rare Condition

Abstract

Isolated paraneoplastic myelopathy (IPM) is a rare neurological manifestation of systemic cancer and represents an intermediate-risk phenotype of disease according to the diagnostic criteria for Paraneoplastic Neurologic Syndromes (PNS). Here, we present the case of a 47-year-old woman who developed subacute cervical myelopathy and was then diagnosed with breast cancer. Through this lens, we provide a discussion of current literature on IPM. Over four months, our patient developed progressive tetraparesis, hypoesthesia with C3 level, and urinary retention. The first MRI was negative, but a four-month-control MRI showed a T2-hyperintense spinal lesion (C2–C7 and T2–T4). Cerebrospinal fluid (CSF) analysis was normal. Infective and autoimmune screening, including onconeural, anti-MOG, and aquaporin-4 antibodies, was unremarkable. The total-body CT scan was negative, but total-body PET-CT scan evidenced an enlarged axillary lymph node, with the detection of breast cancer cells at fine-needle aspiration. Despite negative mammography, a breast MRI confirmed a mammary nodule, which was removed, and a ductal infiltrating breast carcinoma diagnosis was made. Her neurological condition partially improved after steroid therapy. Our final diagnosis was probable IPM, according to PNS criteria. This rare condition affects most frequently middle-aged women and is often associated with breast and lung cancer, even if two-thirds of patients’ cancer diagnosis is subsequent to the onset of neurological deficits. Clinical presentation is often subtle, and CSF analysis, neuroimaging, and onconeural autoantibodies could be negative or non-specific. However, if the suspect of paraneoplastic disease is strong, cancer should be searched thoroughly since early diagnosis and treatment are associated with a better outcome.