Masahiko Oguro

Renal histology in a patient with TAFRO Syndrome: A case report

An 84-year-old Japanese man was admitted due to anasarca, thrombocytopenia, systemic inflammation, and progressive renal insufficiency, resistance to diuretics, glucocorticoid therapy, and plasma exchange. Renal biopsy showed diffuse endocapillary proliferation and mesangiolysis without any immune deposits. Tocilizumab suppressed systemic inflammation, resulting in improvement of anasarca and renal dysfunction, but thrombocytopenia persisted and platelet-associated IgG antibody was elevated. Although romiplostim was effective for thrombocytopenia, the patient died of aspiration pneumonia after cerebral hemorrhage. Autopsy showed hyaline vascular-type Castleman disease-like lymphadenopathy and reticulin myelofibrosis with an increase of megakaryocytes. Renal finding showed that endocapillary injury improved, and collapsed glomeruli were noted. This patient fitted the criteria for TAFRO (thrombocytopenia [T], anasarca [A], fever [F], reticulin myelofibrosis [R], and organomegaly [O]) syndrome. The clinical course suggests that 2 factors, including overproduction of interleukin 6 and autoimmune-mediated thrombocytopenia via thrombopoietin receptor, may have contributed to the pathogenesis of TAFRO syndrome in this patient.

Renal-limited Cryoglobulinemic Vasculitis: Two Case Reports

Cryoglobulinemic vasculitis (CV) presents with systemic manifestations, including renal disease, arthritis, peripheral neuropathy, and muscle weakness. We encountered two patients who developed severe nephrotic range proteinuria; however, extrarenal manifestations were not noted during the clinical course. A renal biopsy revealed typical membranoproliferative glomerulonephritis (MPGN) with huge thrombus-like endothelial deposits and predominant IgM positivity, but electron microscopy did not reveal any definite microtubules. Immunosuppressive therapy and plasmapheresis were only partially effective, and the improvement was not durable. Biological therapy with rituximab (RTX) had no effect. Renal-limited CV should be recognized as a subset of essential CV.

Transcatheter Arterial Embolization Therapy for Huge Renal Cysts: Two Case Reports

We encountered 2 patients with symptomatic huge simple renal cysts. In case 1, 4,000 mL of cyst fluid was drained via a catheter, but intracystic bleeding occurred immediately afterwards. Transcatheter arterial embolization (TAE) was performed, after which the bleeding stopped, and cyst drainage was repeated successfully. After 2 years, the total cyst volume was reduced from 11,775 mL to 75.4 mL. In case 2, TAE was performed prophylactically before drainage. Subsequently, 9,400 mL of fluid was removed from multiple cysts. After 1 year, the total cyst volume was reduced from 9,215 mL to 633 mL without bleeding. Based on these 2 cases, prophylactic TAE before drainage may be useful in patients with huge renal cysts.

Tolvaptan for the Treatment of Enlarged Polycystic Liver Disease

A 44-year-old Japanese woman with autosomal dominant polycystic kidney disease was admitted to our hospital for evaluation of abdominal distension. Her eGFR was 53.7 mL/min/1.73 m2. Total kidney volume was 2,614 mL. Tolvaptan (60 mg/day) was started to treat renal involvement. The patient’s abdominal fullness began to improve and liver volume, indicating advanced polycystic liver disease (PLD), decreased from 9,750 mL to 8,345 mL after 17 months of tolvaptan treatment, though there was no significant change in kidney volume. This case indicates that tolvaptan may be a therapeutic option for hepatomegaly in patients with symptomatic PLD.

Sjögren Syndrome-Related Membranous Glomerulonephritis Progressing to Membranoproliferative Glomerulonephritis

We report a case of glomerulopathy in a 36-year-old Japanese woman with primary Sjögren syndrome (pSS). The first renal biopsy suggested membranous glomerulonephritis. However, repeat biopsy was performed after 16 years because of increased proteinuria, revealing membranoproliferative glomerulonephritis with mesangial deposits, subendothelial deposits, and subepithelial deposits. Immunofluorescent studies showed predominant deposition of IgG2 and IgG4. This patient was positive for antinuclear antibody and anti-SS-A antibody. Sicca syndrome was confirmed by a positive Schirmer test and positive Rose Bengal test. Therefore, pSS-related glomerulopathy was considered to be the most likely diagnosis.