ANCA-associated vasculitis with crescentic glomerulonephritis and papillary thyroid carcinoma: A case report

Rationale: ANCA-associated vasculitis (AAV) is an autoimmune disease. Renal involvement in AAV can manifest as crescentic glomerulonephritis (CGN), which can lead to rapidly progressive renal failure. AAV with crescentic glomerulonephritis complicated and papillary thyroid carcinoma remains rare. The purpose of this report was to enhance the understanding of the diagnosis and treatment of AAV combined with crescentic glomerulonephritis and papillary thyroid carcinoma, reduce misdiagnosis and missed diagnosis, and for the patient with AAV, attention should be paid to screening for cancer, and multi-disciplinary collaboration is required for diagnosis and treatment. Patient concerns: A 49-year-old female patient was admitted to our hospital because of weakness and poor appetite for the past 2 weeks and lower limb edema for the past 3 days. Pathological examination of the renal biopsy specimen showed large cellular crescents and the pathology of the thyroid tissue revealed papillary thyroid carcinoma. Diagnoses: This patient was diagnosed with AAV with crescentic glomerulonephritis complicated and papillary thyroid carcinoma. Interventions: Treatment with 500 mg/day methylprednisolone for 3 days (A total of 2 times, with an interval of 2 weeks between each time)and then 40 mg/day intravenously, cyclophosphamide 1 g pulse therapy and plasma exchange, hemodialysis and resection of the left lobe of the thyroid gland. Interventions, such as anti-infection, correct anemia and electrolyte imbalance, were administered. Outcomes: After treatment, Urine output had returned to normal, the blood creatinine level had remained below 200 µmol/L, and the patient was no longer dependent on hemodialysis. Her PR3 and c-ANCA turned negative. The thyroid cancer did not recur after follow-up of 1 year. Lessons: AAV combined with papillary thyroid carcinoma is very rare, especially AAV with crescentic glomerulonephritis and papillary thyroid carcinoma. The pathogenesis between the 2 is still not clear. In addition to considering immunosuppressive agents, it is still necessary to consider the common pathogenic pathways of AAV itself or between AAV and cancers. When diagnosing AAV, attention should be paid to screening for cancer, and multi-disciplinary collaboration is required for diagnosis and treatment.