First Reported Association of Subcutaneous Panniculitis-Like T-Cell Lymphoma (SPTCL) and C3 Glomerulopathy with Renal-Limited Thrombotic Microangiopathy (TMA)

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Introduction: SPTCL constitutes <1% of peripheral T-cell lymphomas, with a 5-year survival of >80%. We report the first case of C3 glomerulopathy (C3G) with renal-limited TMA associated with SPTCL. Case Description: A 71-year-old African American woman with history of hypertension, presented for a gradually spreading, hyperpigmented indurated plaque on the right thigh for 2 months, punch biopsy demonstrated SPTCL. In three weeks she developed similar lesions on both calves and right forearm. She was admitted for an elevated creatinine (2.74mg/dl; 0.82mg/dl baseline), lactate dehydrogenase (1471U/L), and uric acid (8.3mg/dl). Hemoglobin was stable, platelets and renal imaging were normal and urine protein-to-creatinine ratio showed new proteinuria (1410mg/g). She developed progressive renal injury requiring hemodialysis. Infectious and autoimmune work up remained negative except ANA of 1:320. Hemophagocytic lymphohistiocytosis and lupus were ruled out. Pulse dose steroids (250mg for 3 days) was given due to concerns for rapidly progressive glomerulonephritis. Kidney biopsy showed TMA with global glomerulosclerosis, 65% IFTA, without endocapillary hypercellularity, sclerosis or crescent formation. Immunofluorescence showed glomerular capillary wall and mesangium staining for C3 (4+). She completed 1.8g/m2 of fractionated cyclophosphamide (CYC) and 1.5mg/kg orally for 6 months. She received eculizumab, with a plan to continue pending complement work up. Despite therapy and improvement in urine output, she continued to be dialysis dependent. Discussion: Direct association of complement activation with SPTCL is not reported, but there is growing evidence on complement dysregulation with tumorigenesis. As complement plays a role in immune surveillance against malignant cells, modified expression of complement proteins and regulators by tumor microenvironment can lead to over activation of complement pathways (1). We propose that SPTCL may contribute to complement dysregulation and resulted in renal-limited TMA in our patient. CYC was used to treat SPTCL and eculizumab for C3G and renal-limited TMA findings with success (2). Further understanding of mechanisms driving complement dysregulation with specific tumors are needed to explore potential treatment options.

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