Primary squamous cell carcinoma with sarcomatoid differentiation of the kidney associated with ureteral stone obstruction: A case report.

BACKGROUND: Primary squamous cell carcinoma (SCC) with sarcomatoid differentiation of the kidney was rarely reported. This disease is usually related to renal stones, and due to a lack of symptoms and radiological features, patients usually attend the hospital with late stage disease. CASE SUMMARY: A 54-years-old female presented with left flank pain and an abdominal mass for 6 mo. Imaging studies revealed that the left kidney was enlarged and massive hydronephrosis was present. A stone was seen in the ureteropelvic junction. The patient subsequently underwent left radical nephrectomy, and histopathological examination of the mass revealed a poorly differentiated renal SCC with sarcomatoid differentiation. After primary surgery, the patient received four cycles of tirelizumab. Four months later, the patient developed adrenal, lymph, and uterine appendage metastases. CONCLUSION: SCC of the kidney has a poor prognosis, and should be considered in patients with a renal mass, long-standing urinary calculi and massive hydronephrosis.

Immunoglobulin G4-related kidney disease involving the renal pelvis and perirenal fat: A case report.

BACKGROUND: Immunoglobulin (Ig) G4-related disease (IgG4-RD) is an autoimmune disease associated with chronic and progressive inflammation and fibrosis. It is difficult to differentiate IgG4-RD involving the kidney from infectious diseases and malignancy on imaging. CASE SUMMARY: We report the case of a 51-year-old Chinese man whose abdominal computed tomography scan showed diffuse bilateral enlargement of the kidneys and perirenal fat, thickening of the renal pelvic walls, and hydronephrosis of the right kidney. Relevant laboratory test results showed a serum creatinine level of 464 µmol/L. The patient was diagnosed with acute renal failure and was started on intermittent hemodialysis. Further tests revealed high serum IgG4 levels (20.8 g/L) and an enlarged right submaxillary lymph node. Biopsy and histopathological examination of the enlarged node led to the diagnosis of IgG4-RD. After corticosteroid therapy, his serum creatinine level quickly decreased to near normal levels. CONCLUSION: IgG4-RD affecting the renal pelvis or perirenal fat is rare, with atypical imaging features. Multidisciplinary consultation is critical for accurate diagnosis and treatment of this disease. Suspected cases should undergo biopsy to avoid misdiagnosis.