Ceroid Lipofuscin in Renal Tubular Cells in Hermsky Pudlak Syndrome (HPS): An Unexplored Entity

Introduction: HPS is a rare autosomal recessive disorder of lysosomes and lysosome related organelles (LOR) resulting in defective oculocutaneous pigmentation and bleeding diathesis. 11 clinical subtypes have been identified so far with a relatively higher prevalence reported in Puerto Rico. While pulmonary manifestations are well known, the renal component of HPS remains unstudied and under-reported. Here, we report kidney biopsy findings in HPS. Case Description: A 53 year old male from Puerto Rico with bilateral lung transplant (12/2020) for pulmonary fibrosis related to type 1 HPS and baseline stage G3bA3 CKD presented with SOB and AKI on CKD (increase in baseline serum creatinine from 1.8-2.1 to 4.4 mg/dl) with 3.9 gm/gm albuminuria (baseline 0.57 gm/gm). Urinalysis revealed glucosuria since 2021 with no h/o DM. Kidney biopsy findings revealed acute tubular injury and ceroid lipofuscin deposition in tubular epithelium as shown in Figure 1, similar to prior lung biopsy findings (Figure 1). Discussion: Renal involvement in HPS is characterized by ceroid lysosomal deposition, yet the incidence/prevalence of biopsy proven kidney involvement is not known. In a report of 49 patients with HPS, 20% had creatinine clearance lower than 90 ml/min/1.73m2 (9 out of 45 patients with available data), the pathophysiology of such a finding neither explained nor explored. To our knowledge, our case is the first to report ceroid disposition in both lung and renal tissue in the same patient.Figure 1: Kidney and lung biopsy findings. A) H&E section with ceroid tubular deposition. B) H&E section with mild glomerular mesangial expansion and ceroid tubular deposition. C) EM section with ceroid tubular deposition. D) Lung biopsy with ceroid deposition.