Focal segmental glomerulosclerosis in association with Cushing's disease

Focal segmental glomerulosclerosis (FSGS) may be idiopathic or secondary to a variety of causes. Clinical distinction between primary and secondary forms of FSGS has crucial therapeutic consequences. Whereas the former may respond to immunosuppressive therapy, treatment of secondary forms of FSGS must aim to resolve the underlying diseases. Although the combination of nephrotic syndrome and Cushing's syndrome has been described anecdotally, the causal relationship between these two diseases remains controversial. We report herein a 37-year-old man who presented with lower extremity pitting edema. Heavy proteinuria and mild renal insufficiency prompted to perform a kidney biopsy and the specimen showed FSGS. On the other hand, admission physical examination was notable for a Cushingoid appearance. After endocrinological investigations, the patient was diagnosed as having Cushing's disease caused by pituitary adrenocorticotropic hormone-producing microadenoma. Immunosuppressive therapy for the treatment of FSGS was not carried out and we treated his Cushing's disease with transsphenoidal resection of the pituitary microadenoma. Surprisingly, resolution of heavy proteinuria occurred when the patient's physical features characteristic of Cushing's disease were gradually resolved 3 months later. This case suggests a possible association of Cushing's disease with FSGS.