Ectopic Paragonimiasis Presented as Omental Cystic Masses

Ectopic paragonimiasis has been diagnosed in many organs, such as the mesentery, peritoneum, omentum, diaphragm, pleura, liver, ovary, central nervous system and subcutis. However, simultaneous involvement of the peritoneum, mesentery and omentum is relatively unusual. A 52 years old woman, who visited our hospital because of abdominal pain, is the subject of this report. A CT scan showed an approximate 3.9x9.0 cm sized omphalomesenteric duct cyst in the left paraumbilical area of abdomen. An explorative laparotomy was performed, and the pathologic diagnosis was nonspecific chronic inflammation, with diffuse foreign body granuloma due to parasitic eggs. Postoperatively, the immunoserologic test for paragonimus wetermani was positive. A case of peritoneal, mesenteric and omental paragonimiasis, presenting as omental cystic masses, is presented, with a brief review of the literature.

MR Imaging-Histopathologic Correlation of Radiofrequency Thermal Ablation Lesion in a Rabbit Liver Model: Observation during Acute and Chronic Stages

OBJECTIVE: To determine the ability of MR imaging to detect the pathological changes occurring in radiofrequency (RF) thermal lesions and to assess its accuracy in revealing the extent of tissue necrosis. MATERIALS AND METHODS: Using an RF electrode, thermal lesions were created in the livers of 18 rabbits. The procedure involved three phases. In the acute phase, six animals were killed the day after performing thermal ablation with RF energy, and two on day 3. In the subacute and chronic phases, eight rabbits underwent percutaneous hepatic RF ablation. After performing MR imaging, two animals were sacrificed at 1, 2, 4, and 7 weeks after the procedure, and MR-pathologic correlation was performed. RESULTS: In the acute phase, the thermal ablation lesions appeared at gross examination as well-circumscribed, necrotic areas, representing early change in the coagulative necrosis seen at microscopic examination. They were hypointense on T2-weighted images, and hyperintense on T1-weighted images. Gadolinium-enhanced MR imaging showed that a thin hyperemic rim surrounded the central coagulative necrosis. In the subacute phase, ablated lesions also showed extensive coagulative necrosis and marked inflammation at microscopic examination. Beyond two weeks, the lesions showed gradual resorption of the necrotic area, with a peripheral fibrovascular rim. The size of lesions measured by MR imaging correlated well with the findings at gross pathologic examination. CONCLUSION: MR imaging effectively demonstrates the histopathological tissue change occurring after thermal ablation, and accurately determines the extent of the target area.