Mimic of Peritoneal Carcinomatosis: Protein-Losing Enteropathy Revealing HRAS-Driven Generalized Lymphatic Anomaly

Complex lymphatic anomalies can present with a protein-losing enteropathy. A 25-year-old woman presented with steatorrhea, weight loss, anasarca, and hypoalbuminemia. Abdominal computed tomography revealed diffuse peritoneal soft tissue lesions concerning for carcinomatosis. Omental biopsies and magnetic resonance lymphangiography established generalized lymphatic anomaly. Targeted genetic sequencing identified a novel postzygotic HRAS insertion mutation. She was started on a low-fat diet, sirolimus, and trametinib monotherapy with modest symptomatic response. However, she continued to have severe malnutrition. Alternating therapy of sirolimus and trametinib is ongoing. This is the first reported case of protein-losing enteropathy as the presenting manifestation of an HRAS-driven generalized lymphatic anomaly.