[Angiolymphoid hyperplasia with eosinophilia involving the kidney: a report of three cases with literature review].

Objective: To report the clinical and pathological characteristics of renal involvement in angiolymphoid hyperplasia with eosinophilia (ALHE).

Methods: Three cases of ALHE with renal involvement were diagnosed in our hospital. Routine pathological examination and immunohistochemical study of CD(31), CD(34) and F(8) of lymph node and renal biopsy specimens were performed and the clinical and pathological features were analysed.

Results: All three patients were male. Subcutaneous mass in the neck and head region accompanied with proteinuria and renal function impairment were the clinical characteristics of the three patients. Peripheral blood eosinophilia with elevated IgE level was detected in all the 3 patients. The level of serum immunoglobulins and complements were abnormal in 2 of them. They were sensitive to corticosteroid and cyclophosphamide therapy, but one case showed a recurrence after the withdrawal of immunosuppressive agents. Histopathological examination of lymph node and renal tissue showed a prominent proliferation of small vessels lined with hypertrophic epitheloid endothelial cells, which led to a narrowed or even closed vascular lumen. Diffuse infiltration of eosinophils, lymphocytes and plasma cells was identified around the hyperplastic vessels. With immunohistochemical study, CD(31), CD(34) and F(8) were positive in hyperplastic endothelial cells. Renal lesions were mainly distributed in tubulointerstitial area, while one case exhibited membranous nephropathy (stage I).

Conclusion: ALHE with renal involvement is not rare in our country. The clinical and pathological characteristics of ALHE suggested that it might belong to an entity of angiolymphoid hyperplasia associated with allergic response.