Abstract: TH-PO616

LECT2 Amyloidosis – An Entity in Elderly Hispanics with Distinct Pathologic Features

Session Information

Category: Nephrology Education

  • 1302 Fellows and Residents Case Reports

Authors

  • Raj, Nilin, Rush University Medical Center, Chicago, Illinois, United States
  • Whittier, William Luke, Rush University Medical Center, Chicago, Illinois, United States
  • Cimbaluk, David J., Rush University Medical Center, Chicago, Illinois, United States
Background

Leukocyte chemotactic factor 2 amyloidosis (ALECT2), discovered in 2008, is characterized by renal and liver involvement. It mainly affects elderly Hispanics and typically presents with a bland urine, subnephrotic proteinuria, and progressive CKD. Histologically, ALECT2 has a preferential interstitial involvment. Diagnosis is made by liquid chromotagraphy mass spectrometry (LC/MS) of affected tissue.

Methods

A 71 y/o Mexican man presented with a 2 month history of gross hematuria. PMHx includes recently diagnosed DM II. His vitals and exam were unremarkable. Creatinine (SCr) 3.8 mg/dl, K+ 5.4 mmol/L, Hgb 6.3 g/dl. UA grossly red, 1+ protein, large blood, and >300 RBCs. Renal U/S: left renal mass with adjacent lymphadenopathy and blood clots in the bladder. Left radical nephrectomy was consistent with sarcomatoid renal cell carcinoma but the renal cortex revealed tubulointerstitial amyloidosis. Amyloid A stain (-). Immunofluorescence without light chain restriction. EM with characteristic fibrils. Serum/urine immunofixation nl. Serum free κ 8.6, λ 4.5 mg/dl (ratio of 1.9), consistent with CKD. Echo and bone scan were nl. LC/MS confirmed LECT2 type amyloidosis. Following curative surgery, his hematuria resolved and his SCr stabilized at 1.8 mg/dl. Urine p/c ratio 593 mg/g. He was placed empirically on colchicine and at one year follow up his SCr is 1.8 mg/dl.

Conclusion

ALECT2 is an emerging disease that predominantly affects pts of Hispanic ethinicity. Its characteristic demographic predilection and tubulointerstitial involvement should raise suspicion of this disease and alert one to perform LC/MS. Our pt’s diagnosis was discovered by examination of a nephrectomy specimen and confirmed by LC/MS. Althouth there are no known treatments, colchicine impairs chemotaxis of leukocytes and on this therapy his SCr remains stable at one year.

Congo red stain: apple green birefringence under polarized light in the interstitium, sparing the glomerulus.