S3955 A Rare Case of “Malignant” Gastrointestinal Malakoplakia in the Setting of Systemic Lupus Erythematous

Introduction: Malakoplakia is a rare inflammatory disease that can affect any organ system. It is characterized by impaired histiocytes, resulting in incomplete digestion of phagocytized bacteria. The gastrointestinal (GI) tract is the second most common site. Malakoplakia is seen in the setting of immunocompromised states, including being on steroid therapy, chemotherapy and associated with malignancy, post organ transplant, or inflammatory bowel disease. Michaelis-Gutmann (MG) bodies are pathognomonic histological findings of malakoplakia. We present a rare case of colonic malakoplakia that had multiple severe manifestations, mimicking malignancy, and inflammatory bowel disease, in the setting of systemic lupus erythematous (SLE). Case Description/Methods: This is a 68-year-old woman with history of SLE, complicated by esophageal dysmotility (currently on plaquenil, off immunosuppression since November 2024), cytomegalovirus colitis (treated with 2 rounds of valcyte), who was admitted to our hospital from 4/9-4/20 for acute blood loss anemia. The patient was found to have malakoplakia in her colon in 2022, and has been treated conservatively. She has had several colonoscopies with biopsies that have confirmed malakoplakia. Her clinical course has been complicated by recurrent lower gastrointestinal bleeding. Since March 2025, she had been in frequent contact with her Gastroenterologist about ongoing severe abdominal pain and weight loss. Computed tomography scan of the abdomen/pelvis showed a right mid abdominal mass with pelvic lymphadenopathy, which showed florid mass like malakoplakia. The patient has been evaluated by multiple specialist's outpatient including Infectious Diseases, Allergy/Immunology, Rheumatology as well as Hematology/Oncology. During her admission, she was seen by ID who recommended starting a 6-month course of ciprofloxacin. She was evaluated by Rheumatology who recommended to avoid re-initiating immunosuppression. Colorectal surgery did not recommend surgical treatment at this time. Discussion: The literature reports cases of GI malakoplakia causing severe symptoms such as gastric outlet obstruction, hemorrhage, and colonic strictures. Treatment for malakoplakia is very dependent on the patient’s symptoms and presentation, rather than guideline based, given the rarity of the disease. This makes it complicated in our patients’ case to find a definitive cure. We hope that this case gives perspective on the complexity of the disease, and the importance of a multi-disciplinary approach, early on in the clinical course.