Paraneoplastic Opsoclonus-Myoclonus Syndrome as a New and Single Manifestation of Relapsing Disease in a Patient with Small Cell Lung Cancer

Abstract

A 55-year-old woman smoker with a history of cough, weight loss, and chest pain, without neurologic complaints, presented with a mass in the right lung. A bronchoscopy revealed a tumor in the right intermediate bronchus. The biopsy of the lesion showed small cell carcinoma. A FDGpositron emission tomography (PET)-computed tomography (CT) scan was performed and is displayed in Figure 1A. A brain CT was normal. After the diagnosis of limited-stage small cell lung cancer, the patient was treated with four cycles of cisplatin and etoposide combined with normofractionated thoracic radiotherapy (55 Gy) concurrent with the last two cycles. A radiological complete response was assessed, and treatment was completed with prophylactic cranial irradiation. Seven months after complete response, the patient experienced rapidly progressive dizziness and gait instability, followed by gaze disturbances and involuntary, continuous, conjugate, and chaotic saccadic eye movements. The gait disorder worsened, leaving the patient absolutely bedridden. On examination, intermittent myoclonic movements were apparent in the limbs and trunk (see video, part 1, Supplemental Digital Content 1, http://links.lww.com/JTO/A73, which shows these findings). She had neither cognitive impairment nor motor/sensory losses. Brain magnetic resonance imaging and cerebrospinal fluid examination were without noteworthy alterations. Serum antineuronal antibodies (antiHu, anti-Ri, anti-CV2, and antiamphiphysin) were negative. She was diagnosed with opsoclonus-myoclonus syndrome (OMS), and intravenous corticoids were administered for 5 days without improvement. There was no evidence of relapse on the chest CT, and the patient refused a bronchoscopy. A positron emission tomography-CT examination was strictly normal (Figure 1B). Although there was no visible tumor, we considered OMS as its herald, and second-line chemotherapy was started with carboplatin and etoposide in an attempt to reverse her devastating neurologic condition. After just the first cycle, opsoclonus and gait instability improved and the myoclonus resolved completely (see video, part 2, Supplemental Digital Content 1, http://links.lww.com/JTO/A73, which demonstrates her clinical improvement). The patient has completed three cycles of chemotherapy and continued free of recurrence for a total of 31 months, when a right supraclavicular relapse was detected and pathologically confirmed. Nevertheless, paraneoplastic neurologic symptoms did not recur, and third-line chemotherapy with oral topotecan was started.