OVERVIEW
Malignant solid tumor-associated renal disease in a broad sense refers to renal damage caused by direct invasion of the kidney by the tumor, the influence of immune mechanisms, and metabolic abnormalities of the tumor such as hyperuricemia and hypercalcemia. In a narrower sense, malignant solid tumor-associated renal disease refers to renal damage caused by immune mechanisms, also known as paraneoplastic glomerulopathy, with lung cancer, gastric cancer, breast cancer, etc. being the most common.
Etiology
The etiology has not been clearly defined and may be related to the following factors.
1. Tumor antigen is deposited in renal tissues, which stimulates the host to produce anti-tumor antigen antibody and form immune complexes, and then activate the complement system and cause disease.
2. Glomerular microscopic lesions caused by abnormal immunoregulation of T-lymphocytes.
3. Certain tumors secrete vascular endothelial growth factor, which increases glomerular permeability.
4. Tumor diseases produce anti-glomerular basement membrane antibody or anti-neutrophil cytoplasmic antibody, causing crescentic glomerulonephritis.
5. Viral infection, antigen-antibody complexes of viruses are deposited in glomeruli and activate complement leading to nephropathy.
Symptoms
Clinical manifestations include massive proteinuria and/or nephrotic syndrome, which may include microscopic hematuria and mild renal hypoplasia. The common pathological types and clinical manifestations are as follows.
1. Membranous nephropathy
It is the most common pathological type of malignant solid tumor-associated renal disease. It is more common in men over 50 years old, and all patients manifest nephrotic syndrome, and the symptoms of renal disease are relieved with the effective treatment of the tumor, and aggravated with the recurrence of the tumor. The renal pathological manifestations are basically the same as those of idiopathic membranous nephropathy, and a few patients may have polymorphonuclear leukocyte infiltration and hyaline thrombosis in glomerular capillaries, and tumor antigen-antibody complex deposition can be seen in immunological examination.
2. IgG nephropathy
Most of the patients show asymptomatic hematuria and/or proteinuria, and about half of the patients’ urinary abnormalities can disappear in 2-3 months after surgery.
3. Crescentic glomerulonephritis
Clinical and pathological manifestations are similar to those of idiopathic crescentic glomerulonephritis, and some patients may have the corresponding manifestations of vasculitis associated with anti-neutrophil cytoplasmic antibody, and about half of the patients’ renal disease manifestations can be relieved if timely and effective treatment.
4. Microscopic lesion nephropathy
Less common, clinical manifestations of nephrotic syndrome, most patients with normal renal function. Most patients have normal renal function. The age of onset of the disease is more than 65 years old. After the tumor is relieved, the manifestation of renal disease can disappear or get better.
5. Others
Membranoproliferative glomerulonephritis, secondary renal amyloidosis and hemolytic uremic syndrome-thrombotic thrombocytopenic purpura are very rare pathological manifestations of malignant solid tumor-associated renal disease.
Examination
1. Urinalysis
Decreased urine specific gravity, renal tubular proteinuria, and increased urinary micro-protein can be seen. Some patients have moderate proteinuria and erythrocyturia, and the quantitative amount of 24h urinary protein is generally not more than 1.5g/d.
2. Hematologic examination
Blood routine is generally normal, and hematologic malignancies may have typical laboratory findings. Tumor markers have certain significance for suggesting corresponding tumors. Blood urea nitrogen and creatinine can be in the normal range in the early stage, and then gradually increase with the progress of the disease, and in serious cases, the level of uremia can be reached.
3. Renal puncture biopsy
If clinical diagnosis is difficult, renal puncture biopsy can be used to make a clear diagnosis.
4.Other
Gastroscopy and colonoscopy are used for the diagnosis of digestive tract tumor. Chest CT and bronchoscopy are important for the diagnosis of lung cancer. Abdominal CT has diagnostic value for tumors of abdominal cavity and substantial organs. In addition, pleural effusion and ascites to find cancer cells and lymph node biopsy have important reference value for confirming the diagnosis of tumor.
Diagnosis
(1) Diagnosis is based on: ① patients over 50 years old with kidney disease; ② superficial lymph node enlargement or thoracic (abdominal) lymph node enlargement; ③ oedema and weight loss; ④ physical examination reveals masses; ⑤ anemia inconsistent with kidney disease; ⑥ patients with membranous nephropathy.
(2) The diagnosis of malignant solid tumor-associated renal disease must meet the following three criteria: ① complete surgical resection of the tumor or complete remission of the tumor after chemotherapy, and remission of the clinical and pathological manifestations of renal disease; ② positive tumor antigens and/or antibodies in the renal tissue examination, or can exclude other glomerular diseases such as diabetic nephropathy, hepatitis B virus-associated glomerulonephritis, and so on; ③ the recurrence of renal disease after tumor recurrence or aggravation of renal disease. aggravation. Renal biopsy is of great significance in the diagnosis of renal pathology and prognosis.
Differential diagnosis
(1) Diabetic nephropathy: it occurs in middle-aged and old-aged people, manifested as nephrotic syndrome, patients with diabetes mellitus history of more than 10 years, hypertension and diabetic endophthalmitis, history and endophthalmitis are helpful for differential diagnosis.
(2) Renal amyloidosis: renal involvement often presents with nephrotic syndrome. It occurs in middle-aged and old people, and is divided into primary and secondary. Primary disease mainly invades the heart, kidneys, digestive tract, skin and nerves; secondary disease is mostly secondary to chronic suppurative infections and malignant tumors, and mainly invades the kidneys, liver and spleen; tissue biopsy is needed to confirm the diagnosis.
Treatment
The principle of treatment for this kind of disease is: treating the tumor as the mainstay, and treating the kidney disease as a supplement. For those with nephrotic syndrome, thiazide diuretics and/or potassium-preserving diuretics can be applied to reduce swelling; angiotensin-converting enzyme-inhibiting drugs can be used to reduce intraglomerular high pressure and urinary proteins; and glucocorticoids and cytotoxic drugs can be applied to carry out specific treatment. For those who manifest renal failure, treatment can be taken to protect renal function and arrange renal replacement therapy when appropriate.