Disclosures: Rachel K. Teranishi, MD: No financial relationships or conflicts of interest

Case Description: Patient presented to emergency department with six weeks of progressive pain and numbness in a distal pattern in all extremities. She subsequently developed impaired balance and falls, leading to hospital admission. PM&R was consulted for inpatient electromyography (EMG).

Setting: Tertiary care center.

Patient: 78-year-old female with history of hypertension and sick sinus syndrome status post pacemaker who presented with distal extremity pain and falls. Assessment/

Results: Exam revealed decreased light touch, impaired proprioception, and areflexia, with preserved motor function. Nerve conduction studies showed a diffuse axonal sensory nerve process consistent with sensory neuronopathy. Cerebrospinal fluid (CSF) studies showed pleocytosis and spinal MRI demonstrated leptomeningeal enhancement. Diagnosis of sensory neuronopathy led to malignancy workup including CT scan that showed widespread lymphadenopathy in the chest, abdomen, and pelvis. Lymph node biopsy revealed malignant melanoma. The patient was treated with intravenous immunoglobulin and steroids and transferred to an inpatient rehabilitation facility.

Discussion: Paraneoplastic neurological syndromes (PNS) are seen in the setting of malignancy, but they are not a direct result of a tumor, metastasis, or treatment. Subacute sensory neuronopathy (SSN) is a subtype of PNS, most commonly associated with lung or breast cancer or Hodgkin’s lymphoma. SSN typically presents with pain in the extremities and progresses to clumsiness and difficulty walking. Physical exam is significant for deficits in all sensory modalities and diminished reflexes. Immunotherapy has not been shown to be effective and treatment may be better focused on symptomatic control and treating the underlying malignancy.

Conclusion: Malignant melanoma rates have steadily increased over the past 50 years. As early diagnosis is critical and patients with melanoma may present with SSN, awareness of this association is relevant. We present a unique case of malignant melanoma with an initial presentation of pain in the extremities where EMG diagnosis directed further workup and diagnosis of malignancy.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/subacute-sensory-neuronopathy-secondary-to-metastatic-melanoma-a-case-report/