Masked by the Mass: Paraneoplastic Minimal Change Disease Revealing Classic Hodgkin Lymphoma

Introduction: Paraneoplastic minimal change disease (MCD) is a cytokine-driven podocytopathy that rarely complicates classical Hodgkin lymphoma (cHL), and durable renal remission hinges on curing the malignancy rather than prolonged glucocorticoids. Documented in <1% of cHL cases, MCD may precede the lymphoma diagnosis. Case Description: A 25-year-old man presented with three weeks of 3+ leg edema, night sweats, 4.5 kg weight loss, and pleuritic chest pain. CT angiography demonstrated a 9.5 cm anterior mediastinal mass with pleural effusion. Labs: creatinine 4.39 mg/dL, albumin 1.8 g/dL, cholesterol 348 mg/dL, UPCR >6.5 g/g, bland sediment, urine Na <10 mmol. Initial considerations included NSAID-induced acute interstitial nephritis, and high-dose prednisone was empirically started. Kidney biopsy on day 6 revealed normal glomeruli, negative immunofluorescence, and >90% podocyte foot-process effacement confirming MCD. Prednisone was tapered rapidly. Excisional supraclavicular node biopsy proved Stage IIB nodular-sclerosis cHL (CD30/CD15) Nivolumab plus AVD chemotherapy began on day 7. By week 2, creatinine decreased to 1.36 mg/dL, albumin rose to 2.5 g/dL, and UPCR fell to 0.4 g/g. A month review showed complete resolution of edema and ongoing renal remission while he continued nivolumab-AVD Discussion: MCD should be considered in the differential when young adults with lymphoma develop AKI and heavy proteinuria, especially in the absence of hematuria or serologic autoimmunity. The pathogenesis involves cytokine-mediated podocyte injury, including potential IL-13 pathways, leading to the destabilization of slit diaphragms and nephrotic-range proteinuria. This case reinforces several clinical pearls: 1) Biopsy early. KDIGO 2021 recommends biopsy when nephrotic syndrome coexists with AKI or systemic signs. 2) Treat the tumor. >80% remit once lymphoma therapy is initiated; relapse tracks tumor burden. 3) Use Immunosuppression Judiciously. Biopsy should guide decisions; reflex steroid use may be counterproductive.Creatinine trend over time