Diffuse abdominal lymphangiomatosis is a rare and complex disease. It typically presents with non-specific gastrointestinal symptoms and characteristic cystic lesions or tumoral masses on imaging based on the literature to date. This report presents the rare case of a young man with an atypical form of diffuse abdominal lymphangiomatosis in the complete absence of cystic lesions or lymphangioma tumoral masses, thus presenting a unique diagnostic challenge. It was successively treated by surgery, gastric electrical stimulator, sirolimus, and imatinib.

BACKGROUND: Abdominal lymphangiomatosis is a rare benign condition accounting for less than 1% of all the cases of lymphangiomatosis. Management usually involves radical surgical excision; however, depending upon the extent of involvement, patient condition, and absence of complications, conservative management can be also considered.
METHODS: We present the case of a 32-year-old male who presented with short onset abdominal pain and melena. Physical examination findings were within normal limits, except for left lower abdominal tenderness. Upper gastrointestinal endoscopy was within normal limits. Abdominal and pelvic ultrasound and computed tomography (CT) scan revealed numerous, variably-sized cystic lesions within the abdominal cavity, exclusively and extensively affecting the small bowel mesentery with sparing of the retroperitoneum. The diagnosis was confirmed by CT and cytological examination. Radical surgical excision was technically impossible in this patient because of the extensive involvement of the mesentery; therefore, the patient was managed conservatively.
CONCLUSIONS: Extensive and exclusive small bowel mesentery involvement in abdominal lymphangiomatosis is rare. Imaging modalities play an important role in establishing the diagnosis and conservative management can be considered when surgery is technically impossible.

Lymphangioma is an uncommon benign tumor that develops in the lymphatic system. Abdominal lymphangiomatosis is extremely rare in adult patients, and the clinical symptoms of this condition are complicated and atypical. We report a case of abdominal lymphangiomatosis in a 38-year-old female who presented with intestinal bleeding and protein-losing enteropathy, as well as lesions in the lung and bones. A computed tomography scan revealed multiple small cystic lesions without enhancement. Histological examination revealed microscopic cysts were submucosal, with walls composed of thin fibrous tissue, and D2-40 stained highlight the lining of the lymphatic channels by immunohistochemical method. We make a comparison with the cases reported before, and also discuss the diagnose of diffuse pulmonary lymphangiomatosis and Gorham\'s disease.