Pancreas

Primary echinococcosis of the pancreas is rare, with a reported incidence of less than <0.2/100 cases. However, not all cases are reported and the incidence may be somewhat higher.

Clinical signs of pancreatic hydatids depend more on the size and stage of development than on location: they include abdominal pain, jaundice, weight loss, a palpable abdominal mass, and signs of portal hypertension. When a cyst ruptures into the peritoneal cavity, widespread dissemination may occur if not treated by chemotherapy. Surgery is still the method of choice for intact hydatid cysts and is curative in solitary cysts. The results of imaging (US, CT and MRI) are not different from other organs. Ultrasound and CT scans may not always distinguish between ruptured and infected hydatid cysts and abscesses, complicated pancreatic pseudocysts, and cystic neoplasms of the pancreas.

Mesentery, Omentum, Peritoneum, Retroperitoneum and Pelvis

Primary or secondary hydatids may be found anywhere along the omentum, mesentery, peritoneal cavity, retroperitoneum or pelvis in at least 2% of patients. They may be palpable clinically or cause bowel or urinary complaints. When calcified, they may be detected radiologically on plain radiographs of the abdomen and pelvis (Figs. 3.72, 3.73, 3.74A). Otherwise, they may be discovered, often as a chance finding, on ultrasound, CT or MRI (Figs. 3.74 and 3.75).

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Fig. 3.72 Multiple calcified hydatid cysts in the liver, spleen and mesentery. There are at least three calcified mesenteric cysts seen on AP (A) and lateral (B) views of the abdomen. (C) Multiple large mesenteric and peritoneal hydatid cysts seen in a cadaver. AFIP 53-20053-2. (D) A supine radiograph of the abdomen of another patient aged 66 years with multiple palpable "tumors". The patient had abdominal swelling for several months. There is no calcification of the large left upper quadrant mass, but the stomach is displaced medially. Selective celiac arteriography (E) shows superior displacement of the gastric and splenic arteries, but there is no tumor blush and no abdominal neovascularity. The excretory urogram phase shows right hydronephrosis and bilateral hydroureter, due to pressure from the pelvic mass lying between the bladder and rectum shown clearly on the lower CT scan (G). Other cysts are well shown, including one laterally in the right lobe of the liver (F). Hydatid disease should be suspected whenever there are multiple intra-abdominal cysts.

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Fig. 3.73 (A) A huge, faintly calcified mesenteric hydatid cyst compressing the greater curvature of the stomach. The stomach is displaced to the right and the small bowel inferiorly by this unusually large hydatid. (B) Gross specimen of a large E. granulosus cyst in the mesentery. (B courtesy of G.N. Stemmerman, Hilo, Hawaii.) (C) Another huge calcified hydatid cyst overlying the left upper quadrant and lower hemithorax in a different patient, causing extrinsic compression on the esophagogastric junction and fundus of the stomach.

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Fig. 3.74 Plain radiograph and sonograms of mesenteric, retroperitoneal, and pelvic hydatids in 4 patients from different parts of Africa. (A) Large calcified mesenteric hydatid with multiple calcified daughter cysts in the right mid-abdomen of a patient from Zimbabwe. (B) Ultrasound scan of the same patient showing a curvilinear echogenic rim with shadowing indicating calcium in the wall of the cyst. (C) Large mesenteric hydatid with probable daughter cyst in another patient from Zimbabwe. (A-C courtesy of Dr. Sam Mindel, Harare, Zimbabwe.) (D) Retroperitoneal hydatid (arrows) in a Tunisian patient. (Courtesy of Dr. Gharbi, Tunis.) (E) Large hydatid with daughter cyst seen on longitudinal sonogram in the pelvis of another African.

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Fig. 3.75 CT scans of multiple peritoneal and pelvic hydatid cysts in 4 different patients from Tunisia. (A) Large type I peritoneal hydatid lying anteriorly in the upper mid-abdomen between the liver and spleen. There is also a small calcified and collapsed type III hydatid cyst in the liver of this 58-year-old man. (B) A 68-year-old man with multiple multivesicular type II hydatids with numerous daughter cysts in the pelvis. (C) A 50-year-old man with two old but evolutive pelvic hydatid cysts with calcification of the cyst walls and with daughter cysts, suggesting hypermature type II cysts. Note: In the Gharbi classification of hydatids based on cross-sectional (primarily ultrasound) imaging rather than the pathology-based classification of Lewall used in this chapter, these would be type V cysts; the cysts in patient (B) would be type III cysts, and the calcified, collapsing liver cyst in patient (A) would be a type IV cyst. (D) Hydatid cyst in the left lower quadrant of a 35-year-old woman. There is a large volume of peritoneal hydatid fluid septated as a complication of her hydatid disease, with bulging of the anterior abdominal wall in the midline of the lower abdomen. (Courtesy of Dr. Ben Cheikh and Dr. Gharbi, Tunis).