Nickan Research Institute Journal of Renal Endocrinology 2423-6438 6 1 2020 01 01 Focal segmental glomerulosclerosis associated with papillary thyroid carcinoma in a patient with polycystic kidney disease e11 e11 EN Forough Ebrahim Tabar https://orcid.org/0000-0001-5712-7924 Hamed Fallah https://orcid.org/0000-0003-0641-8056 Roghayeh Akbari https://orcid.org/0000-0002-3720-3077 Journal Article 2020 09 11 2020 12 02 Focal segmental glomerulosclerosis (FSGS) is the most common histological pattern of nephrotic syndrome which has been mainly reported in adults with hematological malignancies. However, the association of FSGS with carcinoma especially solid tumor of the thyroid has not been reported. Here, we present a case of nephrotic syndrome developed due to renal failure in a 21-year old woman with autosomal dominant polycystic kidney disease (ADPKD). Pathological examination of renal biopsy revealed the characteristic changes of FSGS. On further evaluation, the patient had right thyroid lobe swelling clinically which result in total thyroidectomy. The pathological study was inconsistent with papillary thyroid carcinoma (PTC). Regardless of the therapeutic interventions, her renal function worsened gradually and she ultimately required hemodialysis. This case presented an unreported co-incidence of PTC and nephrotic syndrome due to FSGS. The underlying mechanism for the development of malignancies after nephrotic syndrome is still unknown. Hence, underlying malignancy should be considered in young adult patients presenting with nephrotic syndrome.