Anti-signal recognition particle myopathy (anti-SRP myopathy) is a rare subtype of immune-mediated inflammatory myopathy characterized by muscle weakness and anti-SRP autoantibodies. Although plasma exchange (PE) is used in severe cases, its role remains unclear. A systematic review was conducted following PRISMA guidelines, identifying 23 patients with anti-SRP myopathy treated with PE. Data on demographics, clinical features, laboratory findings, treatments, and outcomes were analyzed combining individual patient data if available. Sixteen (69.6%) patients were male, with muscle weakness as the predominant symptom in 100% of cases. After PE, most patients showed improvement in symptoms, and the proportion of patients with muscle weakness was reduced (p = 0.001). Relapse occurred in 17.4% of the cases. The incidence of adverse events was low (8.7%). Despite limitations, including a small sample size and heterogeneous data, our systematic review suggests that PE may be effective in inducing remission and controlling symptoms in anti-SRP myopathy, particularly in severe cases. Since evidence on PE in anti-SRP myopathy is limited, further research, including prospective multicenter studies, is warranted to understand better its efficacy and safety and establish its role in treatment algorithms.

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced malignancies, but they may cause a wide range of immune-related adverse events (irAEs). Hepatic toxicity occurs in approximately 1–6% of patients treated with nivolumab and usually presents with a hepatocellular pattern responsive to corticosteroids. The cholestatic-predominant immune-mediated hepatitis seems to respond poorly to immunosuppression. We describe an 87-year-old man with metastatic melanoma treated with nivolumab who developed steroid-refractory, cholestatic-predominant immune-mediated hepatitis after 18 cycles of therapy. Laboratory tests revealed a mixed but predominantly cholestatic pattern (ALT 585 U/L, GGT 2261 U/L, total bilirubin 2.0 mg/dL). Imaging excluded biliary obstruction or hepatic metastases. Liver biopsy showed acute lobular hepatitis with intracanalicular cholestasis and mild bile duct injury, consistent with immune-mediated, drug-induced injury (Ishak score 5). Mycophenolate mofetil produced only partial biochemical improvement. The patient died one month later from influenza A pneumonia in the context of combined immunosuppressive therapy. This case illustrates a cholestatic-predominant phenotype of nivolumab-induced hepatitis, characterized by poor corticosteroid response and incomplete recovery despite second-line immunosuppression. Recognition of this entity is essential, as early introduction of agents such as mycophenolate may improve outcomes. In elderly and frail patients, however, the risks of intensified immunosuppression must be carefully balanced against infection risk, highlighting the need for individualized management and vigilant monitoring.

Background and Clinical Significance: Immune checkpoint inhibitors (ICIs) have transformed the management of advanced solid tumors but can trigger severe immune-related adverse events (irAEs). Among the rarest and most life-threatening is hemophagocytic lymphohistiocytosis (HLH), a hyperinflammatory syndrome driven by uncontrolled immune activation. Case Presentation: We report the case of an 80-year-old man with clear cell renal carcinoma with sarcomatoid features who developed secondary hemophagocytic lymphohistiocytosis (HLH) after receiving four cycles of adjuvant pembrolizumab therapy. Following four cycles of immunotherapy, he presented with persistent fever, pancytopenia, hyperferritinemia (>49,000 ng/mL), hypofibrinogenemia, and elevated soluble IL-2 receptor (>7500 U/mL), fulfilling at least five HLH-2004 diagnostic criteria. Despite treatment with high-dose corticosteroids and intravenous anakinra (100 mg every 6 h), his condition rapidly deteriorated, leading to multiorgan failure and death. Discussion: ICI-induced HLH is an exceptional but increasingly recognized irAE, with fewer than 30 pembrolizumab-related cases reported to date. Diagnosis is challenging due to its nonspecific presentation, which can mimic infection, hepatic toxicity, or disease progression. The pathogenesis is believed to involve excessive activation of cytotoxic T cells and cytokine storm. While established pediatric protocols (HLH-94, HLH-2004) guide management, adult cases often require individualized approaches using corticosteroids and cytokine-targeted therapies such as IL-1 or IL-6 blockade. Conclusions: HLH secondary to ICIs should be considered in the differential diagnosis of patients receiving immunotherapy who develop unexplained fever and cytopenia. Early recognition and prompt initiation of immunosuppressive therapy are critical to improving outcomes in this potentially fatal complication.

Summary: Anti PD1/PD-L1 agents, including pembrolizumab, have revolutionized the oncological treatment of different types of cancer, including non-small cell lung cancer. The most frequent complications associated with this type of treatment are mild and are located at the thyroid, pulmonary or hepatic level. Sarcoid like reaction and mesenteric panniculitis secondary to pembrolizumab treatment are two very rare adverse effects. We present the case of a patient with these complications. Purpose: the treatment of metastatic non-small cell lung cancer has undergone a major change in the last 10 years, largely due to the advent of immunotherapy. Anti PD1 agents such as pembrolizumab have increased the median survival of these patients from 13 to 26 months. Most frequent immunorelated side effects are hypothyroidism, pneumonitis or elevated liver enzymes. However, there are other adverse effects, including sarcoid-like reaction and mesenteric panniculitis, which should be known by the professionals involved in the diagnosis and treatment of this type of patient. We present the case of a 62-year-old man with a history of unresectable and non-irradiable stage IIIB epidermoid lung carcinoma with a PD-L1 expression of 30% in whom pembrolizumab was discontinued after 4 cycles due to immunorelated arthritis. One year later he consulted for severe abdominal pain. A PET-CT scan was performed, showing hilar lymphadenopathy and inflammation of abdominal mesenteric fat. A biopsy of lesions in both areas showed non-necrotizing granulomatous lymphadenitis in hilar adenopathy and patchy fibrosis of mesenteric fat. The picture was classified as sarcoidosis-like reaction and mesenteric panniculitis secondary to pembrolizumab. Anti-PD1 agents cause hyperactivation of the immune system through T-cell proliferation. Sarcoid-like reaction is a very rare complication that can mask progressive tumor disease. Awareness of immunorelated complications by oncologists, internists, and radiologists is important for an appropriate diagnostic approach and targeted test ordering.