Renal Mucosa-Associated Lymphoid Tissue (MALT) Associated End-Stage Renal Disease in a Patient Presenting With Diarrhea.

Extranodal marginal zone lymphoma (MZL) of mucosa-associated lymphoid tissue (MALT) is most commonly found in the GI tract. Other less common anatomical sites for MALT include the skin, intestine, salivary glands, lungs, and ocular adnexa. Isolated MALT of the kidney has only been sporadically reported. Most of the reported cases in the literature present with underlying renal mass and are generally diagnosed post nephrectomy. We present a case of a 73-year-old gentleman with biopsy-proven primary MALT of the kidney who presented with acute kidney injury (AKI) in the background of  colitis. However, our patient did not have a renal mass a renal biopsy was performed due to accelerated deterioration of renal function. Due to the inherent heterogeneity of the disease, it is challenging to have a unifying treatment strategy for MALT with treatment varying with the anatomical site. We also discuss current and prospective treatment strategies for MALT and marginal zone lymphoma in general.