Backtracking cryptic recurrence of esophageal cancer from membranous nephropathy: the detection of glomerular NELL-1 and IgG4.

We reported the detection of neural epidermal growth factor-like 1 (NELL-1) and immunoglobulin G4 (IgG4) on glomerular capillary wall in membrane nephropathy (MN), which led to the discovery of early post-operative recurrence of esophageal squamous cell cancer (ESCC) in a 68-year-old man. Further, NELL-1 was also identified in the cancerous tissue sampled by esophagoscope. Moreover, serum IgG4 percentage seemed to be higher when comparing with both previous reports and another age-matched male with NELL-1-negative MN upon fully recovered ESCC. Therefore, the finding of NELL-1 in a renal biopsy should trigger a detailed workup in search of malignancy, especially with concomitant IgG4 dominance.