Membranous fat necrosis of gall bladder, a case report and literature review

INTRODUCTION AND IMPORTANCE: Membranous fat necrosis is a rare histological finding. Despite its low incidence and lack of clinical significance, it can involve various organs. Majority of membranous fat necrosis cases are diagnosed in breast lumps and skin in comparison to intra-abdominal lesions. There has been only one reported case of membranous fat necrosis of gall bladder in literature. CASE PRESENTATION: A 56-year-old female patient with previous history of diabetes mellitus and hypertension was administered due to abdominal pain and fever. Based on her physical exam, lab data, and ultrasonography, she was diagnosed by cholangitis. After primary care, she went under cholecystectomy. The histological finding of gall bladder revealed crenulated fatty membranes phagocytized by macrophages in Hematoxylin and Eosin (H&E) staining. Moreover, necrosis and giant cells were seen on Sudan black staining. Hence, the diagnosis of membranous fat necrosis in gall bladder was made. CLINICAL DISCUSSION: Membranous fat necrosis occurs when peripheral blood circulation is compromised. Ischemia of fat tissue cause fatty membranous material accumulation acting as foreign bodies. Hence, it can attract inflammatory response. Regarding pathology, phagocyted membranous by macrophages and giant cells is diagnostic. Sudan black, Luxol fast blue (LFB), long Ziehl-Neelsen, and D-PAS are positive in membranous fat necrosis. CONCLUSION: Membranous fat necrosis of gall bladder is a rare entity. This is the second reported case of such diagnosis. Nonetheless, further pathological investigations are necessary.