A 51-year-old man presented with sudden-onset palpitations and dyspnea that had started 8 h earlier. The patient was restless and tachypneic and had persistent vomiting upon arrival. His sensorium and oxygen saturation levels rapidly declined three hours after arrival, and he was placed on a ventilator. On hospitalization day 2, he was removed from the ventilator and claimed that he had consumed a large amount of energy drinks (oral caffeine intake, approximately 1 g). The theophylline level on arrival had been elevated (9.0 μg/mL). Caffeine intoxication should be considered in patients presenting with restlessness, tachypnea, frequent vomiting, lactic acidosis, and electrolyte abnormalities.

An 83-year-old man with hepatocellular carcinoma developed muscle weakness, ptosis, and dyspnea 3 weeks after receiving atezolizumab. Soon after, mechanical ventilation was initiated, which was followed by marked blood pressure spikes. The levels of creatine kinase and troponin-I were significantly elevated, and acetylcholine receptor antibodies were positive. The patient was diagnosed with immune checkpoint inhibitor (ICI)-induced myositis, myasthenia gravis (MG), myocarditis, and suspected autoimmune autonomic ganglionopathy (AAG). After immunotherapy, the serum markers and blood pressure normalized, and he was weaned from the ventilator after five months. To our knowledge, this is the first reported case of AAG secondary to ICI-induced myositis, MG, and myocarditis.

Objective Bronchoscopic lung volume reduction (BLVR) using a one-way endobronchial valve (EBV) can provide clinically meaningful benefits to chronic obstructive pulmonary disease (COPD) patients. Although the Japanese Pharmaceuticals and Medical Devices Agency approved EBVs in November 2022, information regarding the number of Japanese patients with severe COPD eligible for BLVR treatment is still lacking. We therefore screened computed tomography (CT) images of patients with severe COPD using a quantitative CT (QCT) analysis to estimate the proportion of candidates eligible for BLVR treatment with an EBV.

Methods CT scans of COPD patients with Global Initiative for Chronic Obstructive Lung Disease (GOLD) stages 3 and 4 were retrospectively analyzed using QCT to evaluate fissure integrity and tissue destruction. The difference in volume-weighted percentage was measured using the density scores of the target lobe and ipsilateral non-target lobe at -910 Hounsfield units. The target lobe was defined as the most affected lobe, with an emphysema destruction score of >50% for each patient.

Results High-resolution CT scans of 32 patients (GOLD 3=19, GOLD 4=13) were analyzed. The target lobe could not be identified in 1 patient, whereas the target lobes for 8 patients were not surrounded by fissures with ≥80% completeness. Conversely, in 13 patients, the target lobes were surrounded by fissures with >95% completeness. The remaining 10 patients had fissure completeness between 80% and 95% at the target lobes and were considered candidates for collateral ventilation assessment.

Conclusion A QCT analysis showed that 23 of 32 patients with severe COPD could be considered for a thorough examination of BLVR treatment with EBV.

Sinus arrest and inappropriate sinus bradycardia are sinus node dysfunction (SND), which cause loss of consciousness. Cardiac pacing is recommended in patients with symptoms, such as syncope or dizziness. Several conditions can induce these arrhythmias; however, whether or not intracranial infectious diseases, such as herpes simplex encephalitis (HSE), can cause secondary SND is unclear. We encountered a patient with sinus arrest and transient sinus bradycardia associated with HSE. Since cardiac pause was never monitored and the bradycardia improved after HSE treatment, HSE was suspected to be the cause of SND. Although the underlying mechanisms have not yet been completely elucidated, HSE may cause secondary SND.

Objective To investigate the correlation between pancreatic fat deposition and metabolic syndrome (MetS) parameters, focusing on the locations of fat deposition in the pancreas and sex differences.

Methods Degrees of fat deposition in the head, body, and tail of the pancreas were evaluated using computed tomography (CT). We examined the relationships between pancreatic fat deposition and the age, body mass index (BMI), visceral and subcutaneous fat, serum lipid profiles, hepatic steatosis, diabetes mellitus (DM), and hypertension (HTN).

Results In this retrospective study, greater fat deposition was associated with a higher BMI, visceral and subcutaneous fat accumulation, and hepatic steatosis, with the pancreatic head showing the strongest correlation. Correlations of pancreatic fat deposition with the BMI and visceral and subcutaneous fat accumulation were stronger in females than in males, while correlations with hepatic steatosis were stronger in males than in females. In addition, a multivariate analysis did not suggest a direct causal relationship between pancreatic fat deposition and DM and HTN, but there was a significant correlation between pancreatic fat deposition in the pancreatic head and visceral fat area.

Conclusion Pancreatic fat deposition, as evaluated by CT, especially in the part of the pancreatic head adjacent to the ampulla of Vater, is a sensitive indicator of MetS. The correlations between pancreatic fat deposition and MetS parameters tended to be stronger in females than in males. These results may help further elucidate the pathophysiology of MetS and provide opportunities for its diagnosis.

High-altitude pulmonary edema (HAPE) is a life-threatening, noncardiogenic pulmonary edema that occurs in unacclimatized individuals rapidly ascending to high altitudes above 2,500 m above sea level. Until the entity of HAPE was first identified in a case report published in Japan in 1966, the symptoms of severe dyspnea or coma occurring in climbers of the Japan Alps were incorrectly attributed to pneumonia or congestive heart failure. The Shinshu University Hospital serves as the central facility for rescuing and treating patients with HAPE in the region. Over the past 50 years, a series of studies have been conducted at Shinshu University to gain a better understanding of the characteristics of HAPE. This review summarizes the major achievements of these studies, including their clinical features, management, and pathogenesis of HAPE, particularly in the Japanese population.

Human immunodeficiency virus (HIV)-associated CD8+ T-cell skin infiltrative disease with severe erythroderma has rarely been reported. While HIV-positive patients are prone to develop lymphoma, which is often associated with Epstein-Barr virus, polymorphic lymphoproliferative disorder is rare, accounting for <5% of cases. We herein report a 41-year-old HIV-positive man who presented with a fever, erythroderma, and lymphadenopathy and was diagnosed with the coexistence of both diseases. His condition improved significantly with continued antiretroviral therapy. This case suggests that HIV-induced immunodeficiency is central to the pathogenesis of both entities and that improvement of the immunodeficient state is an effective treatment.

Glycogen storage disease type 1a (GSD-1a) is a rare congenital disease. Recently, life expectancy with GSD-1a has been improved by its early diagnosis and management. Complications of diabetes with GSD-1a are extremely rare. The optimal treatment for glucose control using this disease combination remains unclear. The existence of GSD-1a and diabetes can cause both hypoglycemia and hyperglycemia, making glucose control especially problematic. In the present report, α-glucosidase inhibitor (α-GI) and dipeptidyl peptidase-4 (DPP-4) inhibitors improved hyperglycemia without symptoms of hypoglycemia in a patient with diabetes and GSD-1a using intermittent continuous glucose monitoring (isCGM).

Objective This study assessed the efficacy of machine learning in predicting thyrotoxicosis and hypothyroidism [thyroid-stimulating hormone (TSH) >10.0 mIU/L] by leveraging age and sex as variables and integrating biochemical test parameters used by the Japan Society of Health Evaluation and Promotion (JHEP) and the Japan Society of Ningen Dock (JND).

Subjects and Methods Our study included 20,653 untreated patients with Graves' disease, 3,435 untreated patients with painless thyroiditis, 4,266 healthy individuals, and 18,937 untreated patients with Hashimoto's thyroiditis. Machine learning was conducted using Prediction One on three distinct datasets: the Ito dataset (age, sex, and 30 blood tests and biochemical test data), the JHEP dataset (age, sex, and TP, T-Bil, AST, ALT, γGTP, ALP, CRE, UA, and T-Cho test data), and the JND dataset (age, sex, and AST, ALT, γGTP, CRE, and UA test data).

Results The results for distinguishing thyrotoxicosis patients from the healthy control group showed that the JHEP dataset yielded substantial discriminative capacity with an area under the curve (AUC) of 0.966, sensitivity of 92.2%, specificity of 89.1%, and accuracy of 91.7%. The JND dataset displayed similar robustness, with an AUC of 0.948, sensitivity of 92.0%, specificity of 81.3%, and accuracy of 90.4%. Differentiating hypothyroid patients from the healthy control group yielded similarly robust performances, with the JHEP dataset yielding AUC, sensitivity, specificity, and accuracy values of 0.864, 84.2%, 72.1%, and 77.4%, respectively, and the JND dataset yielding values of 0.840, 83.2%, 67.2%, and 74.3%, respectively.

Conclusions Machine learning is a potent screening tool for thyrotoxicosis and hypothyroidism.

Anti-IgLON5 disease shows various neurological manifestations, of which dysautonomia is one of the major symptoms and is rarely improved by immunotherapy. We herein report a patient with anti-IgLON5 disease who showed several autonomic failures, including vocal cord palsy for four months. The patient presented with cognitive impairments, bulbar symptoms accompanied by myorhythmia in the pharynx and tongue, cerebellar ataxia with tremor, motor neuron symptoms in the limbs, gastrointestinal dysfunction, orthostatic hypotension, non-rapid eye movement sleep disorder on polysomnography, and severe vocal cord palsy. Combined immunotherapy improved his symptoms, including vocal cord palsy, suggesting that combined immunotherapy might improve dysautonomia in anti-IgLON5 disease.

Objective Prolonged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been reported in immunocompromised patients, as they poorly develop antibodies against SARS-CoV-2. We conducted a clinical trial to determine the efficacy of Imdevimab/Casirivimab (Imde/Casiri), an anti-viral monoclonal antibody (mAb), for prolonged infection at our institution.

Methods Nine patients with hematological malignancies (six with malignant lymphoma and three with multiple myeloma) in our institution presented with coronavirus disease 2019 caused by SARS-CoV-2 omicron variants (one, five, and one with BA.2, BA.5, and BF.7, respectively; two undetermined). Although not all nine patients developed severe disease, viral mRNA was detected in all patients after treatment with remdesivir or molnupiravir. Imde/casiri was infused 11-49 days after the disease onset.

Results Within seven days of infusion, viral RNA was undetectable in five of the nine cases. Because all seven viruses isolated from patients whose viral RNA became undetectable showed low or no sensitivity to this monoclonal antibody cocktail, the disappearance of viral RNA in these cases may not be attributable to the antibody cocktail.

Conclusion It may be worth considering the use of monoclonal antibodies that show some activity against these virus variants to treat persistent SARS-CoV-2 infection in immunocompromised patients.

An 87-year-old man was referred to our hospital for non-healing ulcers on the right third, fourth, and fifth toes. The patient was diagnosed with chronic limb-threatening ischemia. Pre-treatment angiography of the right lower extremity revealed inframalleolar lesions. We failed to perform endovascular treatment because of severe calcification. Therefore, we treated the patient with a novel low-density lipoprotein apheresis device (Rheocarna^®; Kaneka Corporation, Osaka, Japan). Angiography performed four days after therapy revealed significant improvement in microcirculation. One year after therapy, he managed to avoid major amputation and achieve wound healing. In addition, angiography revealed that the microcirculation was maintained.

A middle-aged woman presented with hypertensive emergency after corticosteroid treatment for Sjögren syndrome-associated multiple mononeuropathy with suspected systemic sclerosis. Hypertensive heart failure with hyperreninemia improved with antihypertensives, including aliskiren; however, she became hemodialysis-dependent. Clinical findings and biopsy-proven thrombotic microangiopathy indicated conditions resembling scleroderma renal crisis (SRC). Severe hypertension and heart failure with hyperreninemia occurred after stopping aliskiren for hypotension due to diverticular bleeding, which improved after the reintroduction of aliskiren. Aliskiren appears to be effective in managing hypertensive heart failure in patients with SRC. Nevertheless, hemodialysis remained necessary in our case, and whether or not aliskiren can restore the renal function is unclear.

An 84-year-old Japanese woman presented with left hemiplegia 8 months after completing chemotherapy for mantle cell lymphoma. Brain magnetic resonance imaging (MRI) revealed a hyperintense lesion extending from the right parietal lobe to the left parietal lobe. Compared with these MRI results, ¹⁸F-THK5351 PET revealed more extensive accumulation. A brain biopsy showed progressive multifocal leukoencephalopathy (PML). Immunohistochemistry and John Cunningham virus (JCV) DNA-polymerase chain reaction indicated JCV infection. Therefore, a diagnosis of PML was made. ¹⁸F-THK5351 PET, indicative of activated astrocytes, clearly depicted PML lesions composed of reactive and atypical astrocytes. ¹⁸F-THK5351 PET may capture fresh progressive PML lesions better than MRI.

A 71-year-old man with advanced lung adenocarcinoma was treated with carboplatin, pemetrexed, and pembrolizumab in June 2020. Pemetrexed and pembrolizumab maintenance therapy were continued until November 2022. A fever and severe fatigue occurred in December 2022; however, the cause of the infection was inconclusive based on the patient's symptoms, imaging findings, and culture tests. Although the patient was administered antibiotics, his general condition worsened. Considering the possible diagnosis of immune-related cytokine release syndrome (CRS), the patient was administered prednisolone (1 mg/kg/day) and showed improvement. In conclusion, CRS can occur even long after the initial administration of immune checkpoint inhibitor therapy.

An 80-year-old woman who developed allergic bronchopulmonary aspergillosis (ABPA) was admitted to our institution in 2023 for an enlarged pulmonary mass lesion. She had developed ABPA in 2017, and corticosteroid therapy had improved the mucoid impaction of the bronchi. Because part of the lesion remained, increased doses of corticosteroid, antifungals, and biologics were administered, but the pulmonary lesion enlarged in 2022. Bronchoscopy showed necrotic tissue in the bronchial lumen, and bronchial washing fluid showed neutrophilic inflammation and fungal hyphae. We subsequently diagnosed her as having chronic pulmonary aspergillosis overlapping ABPA, and voriconazole was started that resulted in shrinkage of the nodules.

A 42-year-old man was referred to our hospital because of anemia. The patient underwent gastroscopy and colonoscopy, but no bleeding site was detected. Abdominal contrast-enhanced computed tomography (CT) showed vascular dilatation along the wall of the small intestine. Small bowel capsule endoscopy and antegrade double-balloon endoscopy (DBE) were performed, and the patient was diagnosed with a small intestinal arteriovenous malformation (AVM). The AVM was clipped using DBE. After clipping, abdominal contrast-enhanced CT and small bowel angiography revealed the disappearance of the AVM. DBE may be a viable therapeutic option, helping avoid surgery and its associated risks.

A 54-year-old woman developed new-onset heart failure and was diagnosed with cardiac sarcoidosis. An implantable cardioverter-defibrillator with biventricular pacing was implanted before immunosuppressive therapy to prevent sudden death. The patient refused oral steroids because she disliked their specific side effects and potential adverse events with long-term use; therefore, methotrexate was chosen as an alternative first-line drug. Nine months after starting oral therapy, ¹⁸F-fluorodeoxyglucose-positron emission tomography revealed remission of sarcoidosis, disappearance of heart failure symptoms, marked improvement in cardiac contractility, and a reduced frequency of ventricular arrhythmias.

The usefulness of greyscale (GS) in salivary gland ultrasonography for Sjögren's syndrome (SS) has been established; however, limited information is currently available on power Doppler signals (PDs), and changes after treatment remain unknown. PDs are considered to represent glandular inflammation, which indicates the worsening of GS in later years. We examined the changes in PDs in three immunosuppressant-treated SS patients. PDs decreased, along with GS and markers of disease activity, after treatment. PDs have the potential to provide insights into glandular inflammation in real time; however, large-scale studies on their clinical usefulness are needed.

Objective The novel coronavirus disease 2019 (COVID-19) pandemic has spread worldwide, and hospitals in Japan have been forced to respond to the situation. This study evaluated the broad-spectrum antimicrobial use before and during the COVID-19 pandemic in an acute tertiary-care hospital.

Methods This single-center, retrospective study was conducted between January 2019 and June 2021.

Patients We reviewed patients treated with three broad-spectrum antipseudomonal agents: carbapenems, tazobactam/piperacillin, and cefepime. Monthly aggregated hospital antimicrobial consumption was measured as days of therapy (DOTs) per 1,000 patient-days, and the monthly incidences of Clostridioides difficile infection (CDI), multidrug-resistant Pseudomonas aeruginosa (MRPA), and carbapenemase-producing Enterobacteriaceae (CPE) were recorded.

Results The median monthly carbapenem-DOTs during the pre-pandemic and pandemic era were 8.4 and 8.2 per 1,000 patient-days, respectively. A time-series analysis showed non-significant changes in the level between periods (coefficients: 2.08; 95% confidence interval [CI]: -2.9 to 7.0; p=0.44). No change in the trend of monthly carbapenem-DOTs was observed after intervention. No post-intervention changes in the incidence of MRPA or CPE were observed; however, the trend in the incidence of CDI per 1,000 patient-days significantly differed between the two periods (coefficient: -0.04; 95% CI: -0.07, 0.00; p=0.01), and a downward trend was observed in the monthly CDI incidence during the COVID-19 period.

Conclusion The consumption of broad intravenous antimicrobial agents has not changed significantly during the pandemic. We need to maintain the quality of medical care, including antimicrobial stewardship, even in specialized resource-limited facilities during a pandemic.

A 26-year-old man presented with a tumor in the left soleus muscle. The tumor was diagnosed as a locally advanced leiomyosarcoma. The patient was treated with irradiation followed by wide resection. One year after surgery, the patient presented with multiple lung metastases. Despite aggressive sequential chemotherapy, systemic metastatic tumors continued to develop. To explore therapeutic options for the patient, we performed DNA-based CGP with FoundationOne^® CDx (F1). F1 identified anout-of-strand rearrangement of the NOS1AP::NTRK1 gene, which has not been previously reported. In contrast, RNA sequencing revealed an in-frame LMNA::NTRK1 gene, which is an oncogenic fusion gene.

We herein report a 61-year-old woman with a history of mitral valve replacement for rheumatic fever who presented with crural edema and ascites. Computed tomography showed massive left atrial (LA) calcification involving the interatrial septum, termed "coconut atrium." Catheterization revealed not only pulmonary artery hypertension but also a large V-wave in the pulmonary artery wedge pressure waveform and a dip-and-plateau pattern of right ventricular pressure. Three-dimensional transthoracic echocardiography confirmed the early attainment of peak LA volume and a decreased LA expansion index. Stiff LA syndrome due to coconut LA results in the development of restrictive right ventricular physiology.

A 63-year-old woman with adult T-cell leukemia (ATL) lymphomatous type developed a mild dry cough. Computed tomography revealed lung lesions with a tree-in-bud appearance during intensive chemotherapy. Antibodies against Mycobacterium avium complex were positive. Bronchoalveolar lavage culture showed growth of M. abscessus complex. Finally, M. abscessus subsp. massiliense was also identified. Sequential use of antimicrobials, including macrolides, was introduced during intensive chemotherapy, and the patient successfully underwent allogeneic hematopoietic stem cell transplantation (AHSCT). This is the first case report of a patient with ATL complicated by M. massiliense lung infection, who was successfully treated with haploidentical AHSCT using various combinations of antimicrobials.

Paroxysmal cold hemoglobinuria (PCH) is a rare disease in adults, and its concurrent presentation with warm-type autoimmune hemolytic anemia (AIHA) has not yet been reported. We encountered a 19-year-old woman with AIHA and a positive Donath-Landsteiner test result identified by a hemolytic attack during blood transfusion. She also showed positive results for the direct Coombs and Donath-Landsteiner antibody tests. After treatment with prednisolone followed by rituximab, the AIHA improved, and the Donath-Landsteiner antibody test result turned negative. Clinicians should be aware that patients may present with concurrent warm-type AIHA and PCH and consider rituximab for its treatment.

Immune checkpoint inhibitors (ICIs) can cause immune-related adverse events (irAEs). There are a few case reports of remitting seronegative symmetrical synovitis with pitting edema syndrome (RS3PE) as an irAE. We herein report a 49-year-old Japanese man who developed acute-onset polyarthralgia and edema of the back of both hands and bilateral lower legs after pembrolizumab administration for lung cancer. The patient's lung cancer was in complete remission, leading to the diagnosis of RS3PE induced by pembrolizumab rather than malignancy. When patients show RS3PE during ICI treatment, rheumatologists should consider the possibility of an irAE after excluding malignancy and systemic diseases.

We herein report a 64-year-old man with heparin-induced thrombocytopenia accompanied by anaphylactoid reaction during hemodialysis. The patient was admitted to our hospital with acute myocardial infarction and developed acute kidney injury after percutaneous coronary intervention. When maintenance hemodialysis with heparin was initiated, the patient developed an anaphylactoid reaction with dyspnea, hypotension, nausea, and vomiting. Laboratory tests revealed thrombocytopenia. Immunoglobulin G antibodies to heparin-platelet factor 4 complexes were positive, and a functional assay showed heparin-independent platelet activation. These results provide a definitive diagnosis of heparin-induced thrombocytopenia. The onset timing supported a diagnosis of 'rapid-onset' heparin-induced thrombocytopenia.

Spinocerebellar ataxia type 14 (SCA14) is a rare form of autosomal dominant cerebellar ataxia caused by mutations in PRKCG. We herein report a case of SCA14 presenting with writer's cramp that predated the onset of progressive ataxia by four years. A 47-year-old Japanese woman had an 11-year history of writer's cramps, followed by unsteadiness. Whole-exome sequencing revealed a heterozygous mutation in PRKCG (p.C142S), leading to an SCA14 diagnosis. Therefore, writer's cramp might be a characteristic extracerebellar sign of SCA14 and can precede the onset of cerebellar ataxia.

An 80-year-old man presented with electrolyte abnormalities, particularly hypocalcemia (3.6 mg/dL). He was diagnosed with bone and lymph node metastases from prostate cancer seven years earlier and continuously received goserelin, bicalutamide, and zoledronate. He later developed gradually worsening hypocalcemia, hypokalemia, hypophosphatemia, hypouricemia, renal dysfunction, and weight loss. Urinary potassium and phosphate loss, renal glucosuria, metabolic acidosis, and a low urine pH (5.0) were observed. Given the acquired onset and clinical course, we diagnosed the patient with zoledronate-induced proximal renal tubular acidosis. In the present case, severe hypocalcemia may have been caused by malnutrition and inappropriate long-term use of zoledronate.

Alice in Wonderland syndrome (AIWS) is extremely rare, occurring more often in young individuals than in older adults. Symptoms of this syndrome typically include an altered body image, size perception, and time perception. However, the pathophysiology and lesions responsible for this syndrome remain unclear. In most cases, specific lesions cannot be identified using computed tomography or magnetic resonance imaging. Two patients with isolated cortical venous thrombosis in the right occipital area experienced transient visual symptoms of AIWS. Furthermore, a literature search indicated that AIWS with visual distortions is associated with right occipital lobe lesions, supporting the findings of our study.

A 48-year-old man presented with a fever and back pain and was referred to our hospital with multiple bone destruction and abscess formation. A sputum examination revealed Mycobacterium intracellulare, and pathological findings revealed an indistinct granuloma and acid-fast bacilli, leading to a diagnosis of disseminated nontuberculous mycobacteriosis. Anti-interferon-γ-neutralizing autoantibodies were detected in the serum, and acquired immunodeficiency was suspected to be the etiology. Antimicrobial chemotherapy was initiated, and the lesions generally regressed. However, only the skull lesions worsened, requiring local resection to control the disease. Currently, the patient is continuing to receive drug therapy with good disease control after debridement.

The prognosis of patients with peritoneal metastases from pancreatic cancer is poor, largely due to massive ascites, which precludes systemic treatment. Two patients with a poor performance status and malignant ascites were treated with cell-free and concentrated ascites reinfusion therapy followed by combined chemotherapy with intraperitoneal paclitaxel, intravenous gemcitabine, and nab-paclitaxel. These patients achieved a survival of 19 and 36 weeks with a relatively good quality of life. Combined intraperitoneal paclitaxel and systemic chemotherapy may provide effective palliative management for some patients with peritoneal metastases from pancreatic cancer.

Hemodialysis (HD)-induced myocardial stunning, characterized by transient left ventricular systolic dysfunction during HD, has been reported to be common and associated with a poor prognosis. However, the pathophysiology is not fully understood. We herein report a case of HD-induced myocardial stunning without obstructive coronary artery disease complicated by coronary microvascular dysfunction (CMD), suggesting that CMD plays a crucial role in the pathophysiology of this disease.

Gastrointestinal pseudo-obstruction (GIPO) is a phenotype of the paraneoplastic neurological syndrome (PNS). We herein report a case of small-cell lung carcinoma (SCLC) with GIPO elicited by an immune checkpoint inhibitor (ICI). A 75-year-old man with SCLC developed intractable intestinal obstruction after receiving one course of anticancer drugs (durvalumab, etoposide, and carboplatin). The serum anti-Hu antibody (Hu-Ab) was positive, and the patient was diagnosed with GIPO. Corticosteroid treatment did not improve the GIPO, and the patient died. There are few reports of GIPO after ICI treatment in patients with lung cancer, so a further investigation will be required to elucidate the mechanism by which ICIs elicit PNS. Checking for neuronal antibodies may help identify patients with SCLC who are at risk of developing PNS due to ICI treatment.