CEN Case Reports最新文献

Lymphoplasmacytic lymphoma (LPL) is a rare, indolent B-cell malignancy, with the IgG subtype being particularly uncommon. We present a case of IgG-type LPL complicated by kidney dysfunction due to light chain deposition disease (LCDD), representing the first documented instance of LCDD-related kidney impairment in this lymphoma subtype. A 65-year-old man presented with lower extremity edema and was found to have significant kidney dysfunction. Laboratory tests revealed elevated serum creatinine, heavy proteinuria, and a markedly skewed free light chain κ/λ ratio. Immunofixation electrophoresis identified an IgG-κ monoclonal protein and Bence Jones protein (κ light chain). Bone marrow biopsy confirmed LPL with a MYD88 L265P mutation, while kidney biopsy demonstrated mesangial proliferation, interstitial fibrosis, and granular κ light chain deposits consistent with LCDD. Given the rarity of IgG-type LPL with kidney involvement, this case underscores the importance of a thorough diagnostic workup in patients presenting with both hematologic malignancy and kidney dysfunction. Early recognition and appropriate management are critical for improving patient outcomes. As non-IgM LPL cases have historically been associated with poorer prognoses compared to Waldenström macroglobulinemia, the identification of underlying kidney complications such as LCDD is essential. Further accumulation of similar cases is needed to establish optimal treatment strategies.

Immune checkpoint inhibitors (ICIs) have substantially improved the prognosis of many cancer patients but are also associated with various immune-related adverse events (irAEs). Kidney irAEs are relatively rare, with acute tubulointerstitial nephritis being the most common manifestation. However, some patients develop ICIs-associated glomerular diseases, including pauci-immune crescentic glomerulonephritis. In this report, we present the case of a 72-year-old man with lung squamous cell carcinoma treated with nivolumab, a monoclonal antibody targeting programmed cell death 1 (PD-1). The patient developed rapidly progressive glomerulonephritis a few weeks after initiating nivolumab therapy. Immunological tests yielded negative results, and a kidney biopsy revealed pauci-immune crescentic glomerulonephritis. Immunohistological examination confirmed programmed death ligand-1 (PD-L1) expression in the glomeruli. Despite intensive therapy, including corticosteroid pulse treatment, the patient's kidney function did not recover, necessitating maintenance hemodialysis. This is the first report demonstrating PD-L1 staining in injured glomeruli caused by anti-PD-1 therapy. Immunohistochemistry for PD-L1 may aid in diagnosing glomerulonephritis related to anti-PD-1 therapy.

We report a case of successful arteriovenous fistula (AVF) creation in a patient in his sixties with Marfan syndrome and end-stage kidney disease (ESKD). While preoperative vascular ultrasound showed a normal radial artery appearance, intraoperative findings revealed easy separation between the inner and outer layers of the vessel wall, requiring a meticulous suturing technique. Histopathological examination of the radial artery revealed features compatible with Marfan syndrome: disrupted elastic fibers, and small spaces with increased accumulation of acidic mucopolysaccharide deposits in the tunica media. This case demonstrates that even when normal on ultrasound, the radial arteries of Marfan syndrome patients harbor significant structural abnormalities, warranting heightened caution during AVF creation.

Acquired hemophilia A (AHA) is a rare autoimmune disorder characterized by coagulation factor VIII inhibitors, leading to severe bleeding. Patients often present with bleeding after invasive procedures, necessitating prompt diagnosis and management. Here, we report the case of an 83-year-old man diagnosed with AHA after experiencing persistent bleeding from a hemodialysis catheter insertion site. The catheter was placed for acute kidney injury (AKI) associated with nephrotic syndrome. Despite prednisolone therapy for nephrotic syndrome, he developed factor VIII inhibitors and significant bleeding, suggesting insufficient immunosuppression. Given his advanced age, renal failure, and recurrent pneumonia, intensified immunosuppressive therapy posed a high risk of infection. Therefore, a hemostasis-centered approach was prioritized. Recombinant activated factor VII (rFVIIa, eptacog alfa) failed to control the bleeding; however, recombinant porcine sequence factor VIII (rpFVIII, susoctocog alfa) proved effective, enabling the safe placement of a long-term indwelling catheter for hemodialysis. To maintain hemostasis, emicizumab was introduced, allowing outpatient hemodialysis without further bleeding. Reports of AHA in hemodialysis patients are scarce. To the best of our knowledge, there have been no prior reports of AHA cases requiring hemodialysis that were successfully treated with susoctocog alfa and emicizumab. This case highlights the potential role of these agents in optimizing hemostatic strategies for AHA patients undergoing hemodialysis.

Membranous-like glomerulopathy with masked Immunoglobulin G (IgG) kappa deposits (MGMID) is a recently described rare entity. MGMID is characterized by a membranous pattern of kidney injury with monoclonal IgG kappa restriction and is recognized and "unmasked" by pronase digestion on formalin-fixed paraffin-embedded tissue using immunofluorescence staining. This technique is necessary to identify peculiar forms of glomerular immune complex deposition, which is essential for diagnosing MGMID. Patients with MGMID are usually young adult women. We report the case of a 9-year-old boy who was referred for evaluation of proteinuria and hematuria. The patient initially showed isolated microscopic hematuria. However, following an infectious episode, macrohematuria developed, leading to the decision to perform a kidney biopsy. A kidney biopsy showed a membranous pattern of injury characterized by immune deposits distributed segmentally in the subepithelial region, forming spikes in the glomerular basement membrane in all glomeruli, and segmental mesangial hypercellularity on light microscopy. Only segmental deposits of C3 were present along the glomerular basement membrane, as shown by immunofluorescence performed on fresh frozen tissue. Paraffin immunofluorescence showed positive IgG and kappa deposition. Only IgG1 deposits were positive among the IgG subclasses. Electron microscopy showed segmental subepithelial electron-dense deposits. Eventually, the patient was diagnosed with MGMID. To the best of our knowledge, this case of MGMID in a 9-year-old boy is the youngest case documented to date. The findings from our case suggest that immunofluorescence staining with pronase digestion on formalin-fixed paraffin-embedded tissue is required in pediatric patients with a membranous pattern of kidney injury showing only C3 staining by routine immunofluorescence on fresh frozen tissue.

A 16-year-old Japanese girl presented to the emergency department with a complaint of increased muscle pain in the thighs and difficulty walking. Laboratory examinations revealed elevated levels of creatine phosphokinase, severe hypokalemia (1.4 mmol/L), hyperchloremic metabolic acidosis with a normal anion gap, and a urinary pH of 7.5. The patient was thus diagnosed with hypokalemic rhabdomyolysis due to distal renal tubular acidosis. Furthermore, the patient was diagnosed with Sjögren syndrome based on a high titer of anti-SS-A antibodies, reduced tear production on the Schirmer test, decreased salivary secretion on the Saxon test, and labial salivary gland pathology. Although her muscle symptoms resolved rapidly with fluid and potassium replacement therapy, hypophosphatemia and hypouricemia persisted. The patient was subsequently diagnosed with Fanconi syndrome based on elevated urinary β₂-microglobulin and pan-aminoaciduria. Following induction therapy with prednisolone, mycophenolate mofetil was added for maintenance based on renal pathology, which successfully reduced the urinary β₂-microglobulin levels. This report describes a case of hypokalemic rhabdomyolysis due to concurrent distal and proximal renal tubular dysfunction in a patient with juvenile Sjögren syndrome. Early detection of renal tubular dysfunction is crucial to prevent life-threatening complications, such as rhabdomyolysis.

A 67-year-old man with a history of pancreatic cancer, diagnosed 2 years ago was referred to the hospital with proteinuria and renal dysfunction. His medical history included hypertension. A renal biopsy was performed to investigate renal damage. Light microscopy revealed membranoproliferative glomerulonephritis without Congo red stain positive deposits. Immunofluorescence findings showed positive staining of immunoglobulin G (IgG), fibrinogen and κ-light chain, but not λ-light chain. Additionally, the IgG subclass showed only IgG1 positive staining. Electron microscopy revealed electron-dense deposits in the mesangial and paramesangial regions. They were arranged in microfiber structures; approximately 30 nm in diameter, in a parallel fixed direction alignment. Notably, a characteristic ladder-like formation was observed within them. Glomerular diseases caused by nonamyloid fibrillar deposits are diagnosed based on the clinicopathological features.　Moreover, mass spectrometry confirmed the presence of monoclonal IgG1κ in the glomeruli. As a result, this disease was diagnosed as an atypical proliferative glomerulonephritis with monoclonal IgG1κ deposits (PGNMID). Here, we report an atypical case of PGNMID characterized by a unique ladder-like formation containing fibrinogen and fibronectin in organized structures.

The primary defect in distal renal tubular acidosis (dRTA) is impaired H⁺ ion secretion in the distal nephron, resulting in a normal anion gap metabolic acidosis. The solute carrier family 4-member 1 (SLC4A1) gene encodes the erythroid and renal anion exchanger 1 (AE1) protein for chloride-bicarbonate exchange. Mutations in the gene can result in hereditary dRTA, red blood cell membrane defect, and hemolytic anemia. Chronic granulomatous disease (CGD) is a rare primary immunodeficiency syndrome caused by NADPH oxidase deficiency, leading to impaired neutrophil and phagocyte function, and thus predisposing the patient to multiple bacterial infections. Melioidosis is a rare infection caused by Burkholderia pseudomallei and is often linked to CGD. Here we present an interesting case of an 8-year-old girl with melioidosis secondary to CGD. Also, she had nephrocalcinosis, metabolic acidosis, hypercalciuria, and anemia. The simultaneous presence of distal RTA (Pathogenic homozygous SLC4A1 mutation on whole exome sequencing) and CGD has not been reported previously and reiterates the importance of detailed clinical evaluation combined with investigations for the long-term management of such complex cases.