Teaching Case

A 63-year-old man was referred to the surgeon complaining of non-specific abdominal pain in the left upper quadrant. In his medical history there was no prior abdominal surgery. The blood tests showed mild leukocytosis.

Contrast-enhanced CT of the abdomen and pelvis revealed inflammatory changes of mesenteric fatty tissue, with attenuation values higher than those of the retroperitoneal or subcutaneous fat. The finding had a left-sided orientation corresponding to jejunal mesentery. Other CT features were: scattered soft-tissue nodules 5-6 mm in diameter, hypodense fatty halo surrounding blood vessels and nodules, as well as peripheral band with soft-tissue attenuation partly surrounding the inflammatory mesenteric mass.
Based on the typical CT features the diagnosis of mesenteric panniculitis was made. The patient was managed conservatively with intravenous administration of steroids for 10 days with remission of the symptoms. After hospital discharge, the treatment was continued with orally administered steroids.
Follow-up CECT after 6 months showed mild decrease in attenuation values of the mesenteric fat, size reduction of the small nodules, as well as decrease in width of the hyperattenuated peripheral stripe.

Mesenteric panniculitis is a rare disorder characterized by a tumour-like expansion of the mesentery due to variable degrees of fat necrosis, chronic inflammation and fibrosis. When the predominant pathologic component is inflammatory or fatty, the disease is known as mesenteric panniculitis. In more invasive stage, when fibrosis and retraction are more dominant, the disease is defined as retractile mesenteritis [1]. Other terms commonly used to describe the disease are: mesenteric lipodystrophy, liposclerotic mesenteritis, lipogranuloma of the mesentery, mesenteric manifestations of Weber-Christian disease and sclerosing mesenteritis [2]. The disease is more common in men, with a male/female ratio of 2-3/1, and the incidence increases with age [3].
Clinical manifestations may be related to the inflammation or to mass effect and include: non-specific abdominal pain, bloating and distension, palpable abdominal mass. Other reported symptoms include fever, anorexia and weight loss [2, 3].
Laboratory tests may be within the normal range or demonstrate non-specific findings, such as mild leukocytosis and elevation of the erythrocyte sentimentation rate.
Contrast-enhanced CT is an excellent imaging modality for detection of this rare disease. CT findings include:
- increased density of mesenteric fatty tissue with some regional mass effect by displacing small bowel loops locally,
- small soft tissue nodules scattered within the hyperattenuating mesenteric mass,
- the «fat ring sign», representing low-density fat surrounding vessels and nodules,
- pseudocapsule limiting the inflammatory mesenteric mass [4].
The definite diagnosis of mesenteric panniculitis is established by biopsy.
There is no standard or approved form of treatment for this disease. Nevertheless, usage of steroids is the most commonly prescribed treatment. Surgery may be attempted if medical therapy fails or in the presence of serious complications, such as bowel obstruction or perforation [2].
CT has a definitive role in this point. Moreover, CT is useful in distinguishing mesenteric panniculitis from other mesenteric diseases and is the optimal study for follow-up.