Segmental Sclerotic Lesions in Transplant Kidney: Insights in the Diagnostic Dilemma
M Asgari, AM Gomes, AB Fogo. Iran University of Medical Sciences, Tehran, Islamic Republic of Iran; Centro Hospitalar de Vila Nova de Gaia, Oporto, Portugal; Vanderbilt University Medical Center, Nashville, TN
Background: Segmentally sclerotic glomeruli in the transplant (Tx) kidney may be due to recurrence of FSGS (Rec FSGS), or occur secondarily (Sec FSGS), e.g. related to hypertension, chronic allograft nephropathy, chronic Tx glomerulopathy or calcineurin inhibitor (CNI) toxicity. We examined nonimmune complex segmental sclerosing lesions in Tx, and classified based on clinical findings, time of diagnosis after Tx, light microscopic and EM findings.
Design: All Tx biopsies with segmental sclerosis and/or extensive foot process effacement (FPE) and negative IF from 1995 till 2006 were reviewed, excluding Tx glomerulopathy. All slides, reports, EM photomirographs, clinical history and follow-up were reviewed. Light microscopic (LM) findings were classified by the Colombia schema. Findings of Sec FSGS such as CNI toxicity, expanded lamina rara interna and limited FPE were assessed, and cases classified as Rec vs Sec FSGS.
Results: Fortytwo patients (29 male, 13 female) met entry criteria. Average age was 3714 years (range 11 to 56). Twenty patients (48%) were African American and 13 (31%) were Caucasian. Twentythree (55%) had nephrotic proteinuria at the time of biopsy. Biopsy interval ranged from 4 days to 8 years after Tx. Twentythree (54%) case were classified as Rec FSGS, 15 (35%) as Sec FSGS and 4 (10%) as likely de novo FSGS. Ten (54%) Rec FSGS cases showed only extensive FPE, four (17%) cellular (CELL), four (17%) collapsing (COLL), and four (17%) not otherwise specified (NOS) lesions. In cases classified as likely Sec FSGS, NOS lesion was the most common morphologic variant, in 6 (40%), followed by 3 (20%) COLL, 2 (13%) CELL and 3 (20%) with FPE and other features of Sec FSGS. Rec FSGS was most common in early biopsies (85% of all FSGS cases in first 6 months). In contrast, 13 (65%) biopsies at > 2 years showed Sec FSGS. Nearly all patients, whether Rec or Sec FSGS, lost their kidney during the following months to years.
Conclusions: Early time of recurrence and extensive FPE were characteristic of Rec FSGS. NOS variant is more common in Sec FSGS, whereas extensive FPE alone is the most common finding in Rec FSGS. COLL, related to CNI toxicity, and CELL lesion can be seen in both Rec and Sec FSGS. We conclude that integrated analysis of LM, EM and clinical data help to differentiate varying etiologies of sclerotic lesions in the Tx.
Category: Kidney (does not include tumors)
Tuesday, March 10, 2009 1:00 PM
Poster Session IV # 188, Tuesday Afternoon