Hence, differential diagnoses and associated diagnoses must be quickly eliminated to start corticosteroids as soon as possible (19)
Hence, differential diagnoses and associated diagnoses must be quickly eliminated to start corticosteroids as soon as possible (19). Nivolumab (Nivo, anti PD-1) and presented at day 10 a grade IV myositis mimicking bulbar palsy with dysphonia, dysarthria and aphagia. In a multidisciplinary setting, she was treated with IV corticosteroids (methylprednisolone 1 mg/kg started at day 10, with a progressive MCB-613 decrease until PPP2R2C 1 mg of prednisone in March 2024), IV immunoglobulins started at day 18 (1.5 g/kg in 2 days, administered monthly, with a progressive decrease and a cessation in June 2022), enteral nutrition, speech therapy and physical therapy, with noticeable improvement. After 4 years of follow-up, and only one infusion of Ipi/Nivo, the melanoma is still in complete response. == Conclusion == We report an ICI-induced severe myositis mimicking bulbar palsy after the administration of Ipi/Nivo. The diagnosis and clinical care management of this rare complication requires a multi-disciplinary work-up. Keywords:immune-related myositis, bulbar palsy, immune checkpoint inhibitors, immune toxicity, ipilimumab/nivolumab == 1. Case presentation == A 57 year-old woman, ECOG 0, with a medical history of locoregional, Hormone MCB-613 Receptor positive (HR+) breast cancer (pT2N2M0: treated by surgery, adjuvant chemotherapy by anthracyclines/cyclophosphamide (EC) and paclitaxel, radiotherapy and anti-aromatase), asthma, Zika and Chikungunya infection, presented in November 2019 a discomfort and burning in the left side pubic area (Figure 1). Then, she noticed a left inguinal adenopathy, increasing in size. Mid-January 2020, she consulted in internal medicine at a general hospital, where lab tests were normal (notably for HIV, plasma protein electrophoresis). An abdomino-pelvic CT scan on January 10, 2020 revealed several adenopathies: left inguinal (17 mm), left external iliac (34 mm), left internal iliac (41 mm) and left latero-aortic (28 mm). The surgical lymphadenectomy revealed a malignant melanoma with sarcomatoid dedifferentiation (PS100-, MelanA-, BRAF-), with NRAS mutation on Exon 3 (p.Gln61Leu). == Figure 1. == Patients timeline. The patient was transferred to our Cancer Center (Institut Paoli-Calmettes, UNICANCER Marseille, France). Physical examination and PET-CT did not reveal the primary site of this melanoma and symptoms quickly worsened (oedema of the left lower limb and the pubis, ilio-femoral venous thrombosis). Tumor board validated a combined immunotherapy with ipilimumab 3 mg/kg (anti CTLA-4) and nivolumab 1 mg/kg (anti PD-1) with a first infusion in March 2, 2020. Two days after immunotherapy, she presented asthenia and severe headaches. Then, on MCB-613 day 8, she noticed the onset of bilateral oedema in the wrists, associated with slight pain in the thumb, rising to the elbow, associated with hyperthermia. On day 10, she also described swallowing MCB-613 difficulties with a sensation of dysphonia. She was admitted in the emergency department: swallowing disorders increased until day 12, with dysphagia to MCB-613 solids preventing any feeding, together with a dysphonia and a sensation of para-cervical stricture. Lab tests revealed hepatic cytolysis (from 10N to 15N), with moderated cholestasis (GGT 1.5N) and elevated CPK (4574 to 5898 U/L, 40N with ULN: 145 U/L) and troponin (53 ng/L, 4.5N with ULN: 11.6). We started IV corticosteroid (1 mg/kg methylprednisolone) and the patient was transferred to the Internal Medicine Department. Hence, the clinical exam revealed a bilateral deficit in digital extension muscles, together with hypoesthesia and dysesthesia of the right inferior limb. Initially, no motor deficit was observed in the lower inferior limbs, but a motor deficit appeared 4 months after the C1D1 (July 2020) in the right foot elevator muscles (4/5) and in the right ilio-psoas muscle (4/5). The 8-finger capillaroscopy revealed branched capillaries, signing organic microangiopathy, as seen in myositis (1). Testing for myositis specific and associated antibodies remained negative, as anti-RAC and anti-MusK antibodies (anti-striational antibodies not tested) and we did not conduct muscle biopsy. Clinical examination and nerve conduction study (NCS) were quickly performed by a neurologist. There was a clinical deficit in ulnar (4/5) and median innervated muscles (2/5) in addition with previously described deficits. NCS assessed tibial and common fibular nerves on lower limbs, and median and ulnar nerves on upper limbs. It showed decreased SNAP and CMAP in the right fibular nerve, left.