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A paraganglioma is a tumor originating in the sympathetic or parasympathetic nervous system. Its diagnosis may sometimes be confusing if it occurs in an atypical site. We described herein a case of a peripancreatic paraganglioma originating in the greater omentum. An asymptomatic, 61-year-old, female patient was referred to our hospital for detailed examination of a peripancreatic mass detected incidentally on computed tomography (CT). The differential diagnosis was a neuroendocrine neoplasm (NEN), and a biopsy using EUS-FNA was performed. Histologically, the tumor cells showed proliferation in solid cell nests and were positive for CD56, chromogranin A, and synaptophysin. These findings and the hypervascularity of the tumor on imaging studies were compatible with NEN. Since the imaging studies did not clearly demonstrate the continuity of the tumor with the pancreas, laparoscopic tumor resection without a pancreatectomy and sampling of the enlarged peripancreatic lymph nodes were planned as treatment. The absence of continuity with the pancreas was later confirmed by intraoperative observation, and the resection was carried out as planned. The resected tumor was pathologically considered as NEN at first in agreement with the preoperative diagnosis. However, several histological findings (such as a zelleballen-like growth pattern, pseudo-inclusion, and strong nuclear atypia compared with the cells' proliferative ability) were atypical for NEN, and paraganglioma was included in the differential diagnosis. Additional immunostainings of S-100 and AE1/AE3 were performed, leading to the final diagnosis of paraganglioma. Paragangliomas should be included in the differential diagnosis of an intraperitoneal mass of uncertain identity with hypervascularity.

We report a rare case of cystic lymphangioma of the greater omentum, which was treated by laparoscopic resection. A 61-year-old man was referred to our hospital for the treatment of a perigastric cystic lesion. Esophagogastroduodenoscopy revealed neither a mucosal lesion nor a submucosal tumor in the stomach. Abdominal contrast-enhanced computed tomography imaging showed a cystic lesion in the ventral side of the lower part of the stomach and no mass lesions in the liver. The patient underwent laparoscopic resection of the cystic lesion. The intraoperative observation confirmed that a well-defined cystic lesion was present wrapped in the greater omentum and located predominantly in the right side. Although the cystic lesion was located directly beside the right gastroepiploic artery and vein, excision of the cystic lesion along with the cuff of the omentum was performed without sacrificing the vessels. Macroscopic examination of the resected specimen showed an ovoid, cystic mass measuring 7.5 × 4.3 cm within the omentum. The pathological diagnosis was “cystic lymphangioma without malignant signs.” Following surgery, the patient remained symptom-free without evidence of recurrence for 6 months. The laparoscopic approach, being minimally invasive, can be considered the most feasible approach for the resection of an abdominal cystic lymphangioma.

Omental abscess due to a spilled gallstone is extremely rare after laparoscopic cholecystectomy. Herein, we report a 68-year-old man who presented with left upper abdominal pain after laparoscopic cholecystectomy for gangrenous cholecystitis. Seven months prior to admission, gallbladder perforation with spillage of pigment gallstones and bile occurred during laparoscopic cholecystectomy. The spilled gallstones were retrieved through vigorous peritoneal lavage. Abdominal computed tomography showed a 3 × 2.5 cm intra-abdominal heterogeneous mass, suspected to be an omental abscess, and ascites around the spleen. Exploratory laparoscopy revealed an inflammatory mass within the greater omentum. Laparoscopic partial omentectomy and abscess drainage were performed, and a small black pigment gallstone was unexpectedly found in the whitish abscess fluid. Abscess fluid culture results were positive for extended-spectrum β-lactamase-producing Escherichia coli and Streptococcus salivarius, which were previously detected in the gangrenous gallbladder abscess. The histopathological diagnosis was abscess in the greater omentum. Postoperative course was uneventful, and the patient was discharged 13 days later. In conclusion, we report a successful case of laparoscopic management of an omental abscess due to a spilled gallstone after LC. It is important to attempt to retrieve spilled gallstones during LC because they may occasionally result in serious complications.

A 30-year-old man was referred to our hospital in October 2006 for asymptomatic free air in the peritoneal cavity found on a plain chest X-ray on a routine health examination. Esophagogastroduodenoscopy (EGD) revealed an ulcer scar and deformity of the duodenal bulb, a healing-phase ulcer in the anterior wall of the upper gastric corpus, grade B esophagitis (Los Angeles grading system), and a sliding hiatal hernia. A test for Helicobacter pylori was negative. Upon obtaining an informed consent (asymptomatic perforation), laparoscopic selective proximal vagotomy, Toupet fundoplication, and small skin incision Finney pyloroplasty were performed. Intraoperatively, extensive adhesions of the greater omentum to the duodenal bulb were found, which were suspected to engulf the cryptic perforation. The patient's postoperative course has been uneventful and, at present, recurrence of the ulcer has not been observed. The presented case is rare considering the absence of surgical history, lack of symptoms, and incidental finding of the intraperitoneal free air during a health examination.

Angiosarcoma, one of the least common sarcomas, occurs most commonly in the skin and soft tissues, and postirradiation angiosarcoma of the greater omentum is extremely rare. Only one reported case of postirradiation angiosarcoma involved the greater omentum. We describe the case of 74-year-old female with a history of cervical cancer treated with abdominal irradiation 5 years before. On admission, she had nausea, vomiting anorexia, and fatigue. She underwent an abdominal computed tomography scan that revealed an irregularly shaped tumor bounded by transverse colon. The patient died on the 34th hospital day. Autopsy revealed that the tumor was composed of anastomosing irregular vascular channels of variable calibers, involving the adipose tissue of the omentum. Histological studies suggested angiosarcoma. The definitive diagnosis was postirradiation angiosarcoma of the greater omentum, which is an extremely rare condition with an overall dismal prognosis.

The rupture or bleeding of a gastrointestinal stromal tumor (GIST) is a life-threatening adverse event that can happen during imatinib therapy, but few such cases have been reported in the medical literature. Here, we report a case of intraperitoneal bleeding from GIST during imatinib therapy. A 75-year-old man was diagnosed with a large GIST with liver metastasis and admitted to our hospital for abdominal pain on the 13th day of imatinib therapy. The pain disappeared after 7 days of hospitalization; however, the patient complained of diffuse abdominal pain 5 days after discharge. He presented with muscular guarding, and abdominal-pelvic CT demonstrated dense ascites. The tentative diagnosis was peritoneal hemorrhage from GIST, and urgent laparotomy was performed. During the laparotomy, we noted hemoperitoneum of approximately 500 ml; we resected a bulky metastatic tumor on the greater omentum and a primary tumor on the jejunum. The patient took imatinib (400 mg daily) from the ninth postoperative day and underwent monthly checkups for 9 months after the surgery. When GIST patients complain of sudden and severe abdominal pain during imatinib therapy, bleeding from GIST should be considered as a possible adverse effect of imatinib.