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Abstract: FR-PO725

A Case of Cronkhite-Canada Syndrome-Associated Membranous Glomerulonephritis: Can Lightning Strike Thrice?

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Strimaitis, Benjamin John, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
  • Chandler, Shaun Patrick, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
  • Francis, Leo, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
  • Pagnis, Rachna Vineet, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
  • Ranganathan, Dwarakanathan, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
  • O Sullivan, Eoin D., Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
Introduction

Cronkhite-Canada Syndrome (CSS) is a rare disorder with less than 500 reported cases, characterized by extensive gastrointestinal polyposis and ectodermal abnormalities. It has been rarely associated with membranous nephropathy (MN). Of the 5 cases of MN associated with CSS in the literature, 3 have been in the context of malignancy, and none have tested PLA2R or thsd7a antibodies.

Case Description

A 60-year-old female of Aboriginal heritage presented for evaluation of proteinuria with an Albumin Creatinine ratio (ACR) of 123 mg/mmol and Protein Creatinine ratio (PCR) of 108 mg/mmol on the background of CCS. Her renal function was reduced with a creatinine-based eGFR of 58mL/min/1.73m2 and a blood pressure of 128/78mmHg. She had a history of bilateral hearing loss since her teens requiring hearing aids but no visual impairment. Her brother had been diagnosed with thin basement membrane disease (TBM) and a maternal aunt with a similar presentation. Serological tests and ultrasonography were unremarkable, and a kidney biopsy demonstrated a classical appearance of MN – which was confirmed to be PLA2R and Thsd7a negative. Electron microscopy confirmed TBM with a mean basement thickness of 180nm. No malignancy suggested by history or examination,nor full body CT imaging or colonoscopy. She was treated with ACE inhibition and proteinuria improved to an ACR of 58 mg/mmoL and PCR of 73 mg/mmoL by six months.

Discussion

This case is the first time that contemporary MN associated antibodies have been tested for in CCS, and suggests MN associated with CCS is not caused by PLA2R and thsd7a antibodies as previously suggested.

Hiccum’s Dictum is the counter to Occam’s Razor, which argues a patient may have as many rare diagnoses as they please. This patient was one of 500 reported cases of CCS, one of 5 reported cases of associated MN and is the only reported case with concurrent active TBM disease. This case highlights the careful consideration which should be give to pre-test probabilities when deciding whether to pursue kidney biopsy (isolated TBM was more likely the diagnosis at initial presentation given the confirmed family history) while acknowledging that lightning can indeed strike thrice.