Laparoscopic abdominal perineal rectal resection for rectal cancer with a horseshoe kidney using preoperative 3D-CT angiography: a case report.

BACKGROUND: A horseshoe kidney is a congenital malformation involving the fusion of the bilateral kidneys and is often accompanied by anomalies of the ureteropelvic and vascular systems. When performing resection of colorectal cancer in a patient with horseshoe kidney, damage to the ureter or excessive renal arteries should be avoided. To achieve this purpose, comprehensive preoperative anatomical assessments and surgical planning are important. Here, we report a case of a laparoscopic abdominal perineal rectal resection for lower rectal cancer with a horseshoe kidney. CASE PRESENTATION: A 79-year-old woman presented with bloody stool and was diagnosed with advanced lower rectal cancer, immediately above the rectal dentate line, without metastasis. A preoperative computed tomography (CT) scan revealed a horseshoe kidney, while a three-dimensional CT (3D-CT) angiography revealed aberrant excess renal artery from the aorta to the renal isthmus. The left ureter ran in front of the isthmus of the horseshoe kidney and presented calculus formation. Laparoscopic abdominal perineal rectal resection was performed with D3 lymph node dissection. During the operation, we mobilized the sigmoid colon mesentery via a medial approach and preserved the left ureter, the left gonadal vessels, and the hypogastric nerve plexus in the retroperitoneum in front of the horseshoe kidney. CONCLUSIONS: We report a rare case of rectal cancer surgery in a patient with a horseshoe kidney. We discuss the anatomical peculiarities of a horseshoe kidney, such as excess renal arteries, inferior vena cava, ureter, gonadal vessels, and nerves, that should be preserved according to the literature. We suggest that preoperative 3D-CT angiography is both useful for revealing the relationship between the vascular system and a horseshoe kidney and helpful when performing laparoscopic surgery for a left-sided colon and rectal cancer to avoid intraoperative injury.

Gastrointestinal stromal tumor of the small bowel complicated by torsion: A case report.

INTRODUCTION: Gastrointestinal stromal tumors (GISTs) are mesenchymal tumors that originate from the gastrointestinal tract wall. Approximately 20-30 % of GISTs originate from the small intestine. GISTs of the small intestine generally present with a palpable mass, distention, and abdominal pain and may exhibit acute abdomen at the onset. Herein, we describe a rare case of a pedunculated GIST of the small intestine complicated by torsion. PRESENTATION OF CASE: A 69-year-old woman presented with lower abdominal pain. Abdominal contrast-enhanced computed tomography showed a 73 × 62 × 57-mm3 tumor in the pelvic cavity with enhanced margins and reduced contrast. It was presumed that the tumor had caused hemorrhagic infarction. Emergency laparotomy was performed, and the pedunculated tumor was found to be twisted 360° clockwise at the pedicle with hemorrhage and necrosis due to torsion. We performed partial resection of the small intestine including the tumor. Histopathological examination revealed tightly arranged spindle-shaped cells with hemorrhage, congestion, and inflammatory cell infiltration. Immunohistochemical staining showed positivity for CD34, CD117, and DOG1. CONCLUSIONS: Torsion of a pedunculated small intestine GIST, although very rare, requires emergency surgery and should be recognized as a cause of acute abdomen in patients with GIST. Immediate surgery is mandatory if torsion of a small intestinal GIST is suspected because the GIST or intestine may become necrotic owing to hemorrhagic infarction.

Primary spindle cell tumor originating from the liver that was difficult to diagnose.

BACKGROUND: It has been reported that hepatocellular carcinoma (HCC) with spindle cell tumor accounts for 1.8% of all HCCs, but spindle cell tumors that do not show an obvious conventional HCC are extremely rare. In this report, we describe a case of resection of a primary spindle cell tumor of the liver that was difficult to diagnose. CASE PRESENTATION: A 75-year-old man presented with fever and right chest pain. He was suspected of a giant primary diaphragmatic tumor of extrahepatic origin by imaging studies. The preoperative differential diagnosis included benign masses such as myxoid sarcoma and schwannoma, and we planned a diaphragmatic resection. Intraoperatively, however, dissection of the tumor from the liver was not possible, requiring an extended right posterior segmentectomy with combined resection of the diaphragm. The patient had a good postoperative course and 1 year has passed since the surgery with no recurrence. The pathology showed that the mass was located just below the hepatic capsule/parenchymal region and was adherent to the diaphragm, but there was no continuity. The morphology suggested a low-grade mesenchymal tumor such as a solitary fibrous tumor and perivascular epithelioid cell tumor, but immunostaining was negative, making the diagnosis difficult. Although some areas of high proliferative activity were observed, finally, the diagnosis of primary spindle cell tumor of the liver with smooth muscle differentiation was made based on the positive results of muscle markers such as αSMA, desmin, and h-caldesmon. CONCLUSIONS: Spindle cell tumor arising from the liver is so rare that preoperative and pathological diagnosis is often difficult to reach. Although further studies are needed to elucidate and better understand this uncommon clinical entity, we consider that complete resection is necessary for the above case, which may contribute to long-term survival.