Endometrioid adenocarcinoma arising from inguinal endometriosis during follow-up for gastric cancer surgery: a case report and literature review.

Malignant transformation of inguinal endometriosis is rare. A 56-year-old woman underwent surgery for advanced gastric cancer 5 years ago and received postoperative adjuvant chemotherapy. She had no recurrence since then. However, 5 years after surgery, contrast-enhanced computed tomography (CT) showed a mass in the right inguinal region suspected to be a hydrocele of the canal of Nuck, with a blood test showing a slightly elevated CA19-9 level (63.0 U/mL). Six months later, CT showed an enlarged mass in the right inguinal region and inflammation in the surrounding area. In addition, both inguinal lymph nodes and those in the right iliac artery area were enlarged, suggesting the possibility of malignancy. For diagnostic purposes, a right inguinal mass was excised. Histopathological examination revealed that it was endometrioid adenocarcinoma with ectopic endometriois as the origin. The differential diagnoses for inguinal masses in women include an inguinal hernia, hydrocele of the canal of Nuck, ectopic endometriosis, lymphoma, and metastatic malignancy. The presence of a primary malignancy in the inguinal region is sporadic but must be differentiated. This is the first case of malignant transformation of inguinal endometriosis developed during postoperative follow-up of another cancer.

Spontaneous rupture of an undifferentiated carcinoma with osteoclast-like giant cells of the pancreas presenting as intra-abdominal bleeding: a case report.

BACKGROUND: Undifferentiated carcinoma is a very rare histologic subtype, representing only 0.8% to 5.7% of all pancreatic exocrine neoplasms. Additionally, spontaneous abdominal hemorrhage is a particularly rare, life-threatening cause. CASE PRESENTATION: A 68-year-old man was taken by ambulance to our hospital because of sudden-onset abdominal pain. Contrast-enhanced abdominal computed tomography revealed a huge mass measuring 99 × 70 mm in the pancreatic tail with enhanced rim staining in the peripheral area. Imaging also showed extravasation and fluid collection beside the tumor. Hence, spontaneous rupture of the pancreatic tumor and intra-abdominal bleeding were diagnosed. Emergency laparotomy was performed because of acute abdominal pain with peritoneal signs. With an intraoperative diagnosis of rupture of the pancreatic tumor, distal pancreatectomy was successfully performed. Histologically, hematoxylin and eosin staining showed round to spindle-shaped, highly pleomorphic mononuclear cells and multinucleated giant cells as well as a component of ductal adenocarcinoma. Immunohistochemical staining showed that the tumor cells were negative for AE1/AE3, whereas the non-neoplastic osteoclast-like giant cells were positive for CD68. Taken together, these results led to a diagnosis of undifferentiated carcinoma with osteoclast-like giant cells. The patient's postoperative course was uneventful. CONCLUSION: We experienced an extremely rare case of spontaneous rupture of an undifferentiated carcinoma with osteoclast-like giant cells presenting as intra-abdominal bleeding. Obtaining a correct preoperative diagnosis is quite difficult at the first evaluation. Undifferentiated carcinoma should be considered as a differential diagnosis in the case with spontaneous rupture of a pancreatic tumor.

Optimizing nodal and staging classification in low rectal cancers with lateral node metastasis: multicentre retrospective cohort study.

BACKGROUND: Patients with lateral node metastasis in low rectal cancers have a poor prognosis. However, variability in patient survival in terms of lateral metastatic status has not been thoroughly investigated. This study was conducted to assess the prognostic value of lateral node involvement and to review nodal classification. METHODS: Patients with stage III low rectal cancers who underwent lateral node dissection were retrospectively reviewed. Two cohorts were set: the first one (1995-2006) was selected using a Japanese multi-institutional database and was used for development of a new nodal system, and the second (2007-2013) was collected from referral institutions for validation of findings. Variables correlated with poor prognosis were investigated. Next, a modified classification of lateral-positive nodal cancers was created. Finally, this new classification was compared with TNM and Japanese classification-based systems according to the Akaike information criterion (AIC) and concordance index (c-index). RESULTS: Overall, 742 and 508 patients were selected for cohorts 1 and 2, respectively. Based on the analyses on cohort 1, patients with two or more lateral metastatic nodes partially spreading into regions outside of internal iliac area exhibited poor prognosis; accordingly, a modified N classification was created, where TNM-N1 and N2a cancers with this feature were upgraded, respectively, to N2a and N2b. The modified N classification yielded the most favourable indices (AIC = 2661.08; c-index = 0.6477) compared with the TNM (AIC = 2662.36; c-index = 0.6457) and Japanese classification-based systems (AIC = 2684.06; c-index = 0.6302). All findings were confirmed by analysing cohort 2. CONCLUSION: A modified nodal system is proposed to account for the significance of lateral node metastasis.

Effectiveness of negative pressure wound therapy with instillation and dwelling after stoma closure: a retrospective and propensity score matching analysis.

The use of temporary diverting stoma has become more common in low colorectal anastomosis to reduce anastomotic complications. Surgical site infection (SSI) at the stoma closure site has been one of the most frequent postoperative complications. The aim of this study was to compare the short-term outcomes between conventional primary suture closure and negative pressure wound therapy with instillation and dwelling (NPWTi-d) therapy following purse-string suturing, using propensity score matching analysis. We retrospectively evaluated the medical records of 107 patients who underwent stoma closure between January 2016 and October 2020. The primary outcome was the proportion of SSI. The secondary outcome was the day of postoperative length of stay. Propensity score matching with one-to-one match was performed for reducing treatment selection bias. Of a total of 107 patients, 67 patients had been treated with conventional primary closure and 40 with NPWTi-d therapy. The propensity score matching derived 37 pairs. The respective SSI proportions were 0% and 16.2% in the groups with NPWTi-d and primary closure (P = 0.025). The respective median days of postoperative hospital stay were 9.0 and 10.0 in the groups with NPWTi-d and primary closure (P = 0.453). NPWTi-d therapy with purse-string suturing was effective in reducing SSI after stoma closure.

[Fracture of a Gastrointestinal Stent during Chemotherapy for Unresectable Advanced Gastric Cancer-A Case Report].

A 79-year-old man with shortness of breath on exertion had right pleural effusion and ascites effusion on CT, and was diagnosed with adenocarcinoma on pleural cytology. Upper gastrointestinal endoscopy revealed a gastric cancer with pyloric stenosis, and biopsy from the same site revealed Group 5(tub2). The patient was diagnosed as unresectable advanced gastric cancer with pyloric stenosis and peritoneal and pleural dissemination. After placement of an uncovered metallic stent for the pyloric stenosis, SOX therapy was started. Three months after stent placement, a CT scan to determine the effect of chemotherapy showed stenosis in the gastrointestinal stent, partial breakage of the stent on the mouth side, and prolapse of the stent into the stomach. There were no symptoms such as abdominal pain, and the patient was placed on standby for retrieval of the dislodged stent. The prolapsed stent was retrieved endoscopically, and a covered metallic stent was additionally implanted as a"stent in stent". The patient has had no further passage obstruction and is currently undergoing chemotherapy. We report a case of fracture of a gastrointestinal stent during chemotherapy for unresectable advanced gastric cancer.

Successful resection of a huge hepatocellular adenoma.

Hepatocellular adenoma (HCA) is a rare benign liver tumor that has been reported to occur particularly more often in women who use contraceptives. A 72-year-old woman with no history of using contraceptives presented to our hospital for further examination of a liver tumor. Contrast-enhanced computed tomography and gadoxetic acid-enhanced magnetic resonance imaging revealed a huge solitary hepatic tumor measuring 83 × 76 mm in segments 4, 5, and 8. The differential diagnoses were cholangiocarcinoma and mixed-type hepatocellular carcinoma. Percutaneous needle biopsies were performed twice, and no malignant components were found. Central bi-segmentectomy of the liver was successfully performed. Immunohistochemical staining showed that ß-catenin was positive in the membrane of the tumor cells, while fatty acid-binding protein, glutamine synthetase, and amyloid A were negative. These results led to a diagnosis of HCA, hepatocyte nuclear factor-1α-inactivated subtype. The patient's postoperative course was uneventful, and she developed no recurrence for 10 months after surgery. We experienced a rare case of benign HCA. Obtaining a correct preoperative diagnosis is sometimes difficult at the first evaluation. HCA should be considered as a differential diagnosis of liver tumors.

Synchronous gastric cancer and primary lymphoma of right adrenal gland: a case report.

This report presents an extremely rare case of synchronous gastric cancer and primary adrenal diffuse large B-cell lymphoma (DLBCL). An 82-year-old man underwent computed tomography, which revealed a heterogeneous appearing and hypodense adrenal mass and a gastric mass with no enlarged lymph nodes in the neck, mediastinum, abdomen, and inguinal region. Upper gastrointestinal endoscopy revealed a protruding gastric tumor. The specimens obtained from endoscopic biopsy were histologically confirmed to be adenocarcinoma. The hormonal findings eliminated functional adrenal tumor. The patient underwent distal gastrectomy with regional lymph node resection for gastric cancer and incisional biopsy of the adrenal mass. Based on the pathological findings, diagnoses of mixed mucinous and tubular adenocarcinomas of the stomach and adrenal DLBCL were confirmed. Postoperation, the patient received rituximab combined with low-dose doxorubicin, cyclophosphamide, vincristine, and prednisone (R-miniCHOP). Six courses of R-miniCHOP were planned, but were completed in only one course at the patient's request. The patient died 2 months after surgery.

Successful treatment of intractable chylous ascites after laparoscopic low anterior resection using lymphangiography and embolization with lipiodol: A case report.

INTRODUCTION AND IMPORTANCE: Chylous ascites (CA) is an infrequent, intractable complication that may arise after abdominal surgery. Although various attempts at treatment have been adopted, to date, none of them have been consistently effective. We describe the successful treatment of CA using lymphangiography and embolization with lipiodol. CASE PRESENTATION: A 79-year-old woman underwent laparoscopic surgery for rectum cancer at another hospital. She was discharged on postoperative day (POD) 9; however, she had to be treated and hospitalized for CA three times until POD 76. She visited our hospital to undergo treatment for CA on POD 90 because the previous conservative treatment had not improved her condition. The computed tomography (CT) scans revealed ascites effusion. We performed lymphangiography and embolization with lipiodol two times. Repeated CT on POD 134 showed that the ascites had not increased. CLINICAL DISCUSSION: Lymphangiography and embolization with lipiodol effectively resolved chylous leakage that occurred after abdominal surgery. Additionally, we compare the features of two groups of cases of CA: one group in which patients were treated by lymphatic intervention and the second in which patients were treated through surgical procedures. CONCLUSION: We were thus able to demonstrate the clinical effectiveness of lipiodol lymphangiography in treating CA.

Postoperative solitary liver metastasis from esophageal squamous cell carcinoma achieving a clinical complete response to chemotherapy with cisplatin and 5-fluorouracil followed by stereotactic body radiotherapy: A case report.

Treatment strategies for distant organ metastasis have changed markedly since the concept of oligometastasis was introduced. The perception that distant organ metastasis is a systemic disease and not eligible for local therapy is now a thing of the past. Therefore, the present report details a case of postoperative solitary liver metastasis from esophageal squamous cell carcinoma (ESCC), which achieved a clinical complete response to chemotherapy with cisplatin and 5-fluorouracil (5-FU) followed by stereotactic body radiotherapy (SBRT). A 76-year-old male patient underwent esophagectomy for lower thoracic ESCC. At 7 months after surgery, abdominal CT revealed a solitary hypovascular mass, 28 mm in size, in segment 7 of the liver. After three courses of chemotherapy with cisplatin and 5-FU, abdominal CT revealed that the liver mass had shrunk to 7 mm in size. SBRT was then administered with a 6 MV X-ray beam generated by a linear accelerator. A total dose of 50 Gy was given in 5 fractions of 10 Gy to the liver mass. At 1 month after SBRT, abdominal CT revealed that the liver mass had disappeared. The patient received no further adjuvant chemotherapy and had no recurrence at 18 months after diagnosis of liver metastasis and 13 months after SBRT.

Laparoscopic repair of diaphragmatic hernia after radiofrequency ablation for hepatocellular carcinoma: Case report.

INTRODUCTION AND IMPORTANCE: We describe the case of a patients with a diaphragmatic hernia associated with radiofrequency ablation for hepatocellular carcinoma who was treated by laparoscopic repair. CASE PRESENTATION: An 82-years-old man with history of HCC with hepatitis C virus-related liver cirrhosis (Child-Pugh B). The patient was treated RFA to HCC for segment 4, 5, 6, 8. After 16 months from latest RFA for segment 8, the patient was admitted to our hospital because of mild dyspnea. Computed tomography revealed a diaphragmatic herniation of bowel loops into the right thoracic cavity. The patients electively underwent laparoscopic repair of the diaphragmatic hernia. The patient was discharged from hospital without any post-operative complications. CLINICAL DISCUSSION: The only treatment to diaphragmatic hernia is surgery, but liver cirrhosis patients limits this possibility. For the surgical treatment of patients with severe cirrhosis, the operation should be carefully assessed. We believe that a laparoscopic approach should be used for repairing diaphragmatic hernia. In the present case, we considered that a laparoscopic approach was safer and more feasible than open laparotomy. CONCLUSION: Diaphragmatic hernia is a rare late-onset complication associated with RFA for HCC. And patients with HCC often have severe liver dysfunction and cirrhosis. A laparoscopic approach is safe and minimally invasive for sever cirrhosis patients.

The technique for less infectious and earlier healing of stoma closure wound: negative pressure wound therapy with instillation and dwelling followed by primary closure.

BACKGROUND: Temporary stomas have been widely used to avoid the risk of complications such as anastomotic leakage after colorectal resection. Stoma closure is relatively easy; however, postoperative surgical site infection (SSI) may be a problem. Various methods have been used to reduce the incidence of SSI. We aimed to evaluate a new technique for stoma wound closure. METHODS: We enrolled patients who underwent stoma closure at our hospital between September 2019 and May 2020. We selected patients who lived far from our hospital and had difficulty visiting the hospital regularly and who agreed to undergo this surgical technique. We used negative pressure wound therapy with instillation and dwelling (NPWTi-d) and delayed primary closure for these patients. RESULTS: Four patients underwent NPWTi-d and delayed primary closure without the occurrence of SSI. The median postoperative hospital stay was 9 days (range: 7-14 days), and the median number of days to confirmation of epithelialization was 11.5 days (range: 10-16 days). CONCLUSION: The combined use of NPWTi-d and delayed primary closure for the stoma wound was very effective. This method may be a valuable new technique for wound management after stoma closure.

[Small Bowel Metastasis of Breast Cancer-A Case Report].

A 69-year-old female had hormone therapy for liver metastasis after surgery for right breast cancer. She came to the hospital with a complaint of abdominal pain and was admitted with a diagnosis of small bowel obstruction. She had previously undergone surgery for an ovarian tumor and was suspected of having an intestinal obstruction caused by adhesions in her pelvis. She promptly improved with conservative treatment of fasting only. In the following months, she developed 2 intestinal obstructions, and CT scan revealed a neoplastic lesion in the small intestine. With the diagnosis of small intestinal tumor, laparoscopic surgery was performed. A neoplastic lesion was found in the ileum. A small bowel resection was performed. She was discharged with a good postoperative course. The pathological results showed breast cancer metastasis in the small intestine. Based on the diagnosis, postoperative chemotherapy has been started. Gastrointestinal metastasis of breast cancer is relatively rare and rarely causes clinical problems. We report a case of small intestinal metastasis of breast cancer.

Proposal of a modified subclassification system for stage III colorectal cancer: A multi-institutional retrospective analysis.

AIM: The prognostic value of the stage III subclassification system based on the Japanese Classification of Colorectal, Appendiceal, and Anal Carcinoma has not yet been clarified. This study aimed to develop a modified system with optimal risk stratification and compare its performance with the current staging systems. METHODS: Clinicopathological data from 6855 patients with stage III colorectal cancers who underwent D3 dissection were collected from a nationwide multicenter database. After determining patient survival rates across 13 divisions based on pathological N stage (N1, N2a, and N2b/N3) and tumor depth (T1, T2, T3, T4a, and T4b), except for T1N2a and T1N2b/N3 due to the small number, we categorized patients into three groups and developed a trisection staging system according to the Akaike information criterion. We then compared the Akaike information criterion of the developed system with those of the current staging systems. RESULTS: The T1N1[rank, 1] division (98.5%) had the most favorable prognosis in terms of 5-year cancer-specific survival, followed by T2N1[2] (93.9%), T2N2a[3] (92.0%), T3N1[4] (87.0%), T3N2a[5] (78.8%), T4aN1[6] (78.7%), T2N2b/N3[7] (77.8%), T4aN2a[8] (75.2%), T4bN1[9] (73.5%), T3N2b/N3[10] (64.7%), T4aN2b/N3[11] (61.5%), T4bN2b/N3[12] (43.0%), and T4bN2a[13] (42.5%). Compared to the categorizations of the Japanese and tumor-node-metastasis systems (Akaike information criterion, 22 684.6 and 22 727.1, respectively), the following stage categorizations were proven to be the most clinically efficacious: T1N1[1 ]-T3N1[4], T3N2a[5 ]-T4bN1[9], and T3N2b/N3[10 ]-T4bN2a[13] (Akaike information criterion, 22 649.2). CONCLUSION: The proposed modified system may be useful in the risk stratification of patients with stage III colorectal cancer who had undergone D3 dissection.

Successful management of gastric remnant necrosis after proximal gastrectomy using a double elementary diet tube: a case report.

BACKGROUND: The stomach has many incoming vessels and is resistant to ischemia due to the rich microvascular network within its submucosal layer. Although reports of gastric remnant necrosis after gastrectomy have been rare, mortality rates remain substantially high when present. A double elementary diet (W-ED) tube, which can be used for both enteral feeding and gastrointestinal tract decompression, has been developed for anastomotic leakage and postoperative nutritional management after upper gastrointestinal surgery. The current report presents a case of gastric remnant necrosis after proximal gastrectomy that was successfully managed through conservative treatment with a W-ED tube. CASE PRESENTATION: A 73-year-old male was referred to our hospital for an additional resection after endoscopic submucosal dissection (ESD) for gastric cancer. Endoscopic findings showed an ESD scar on the posterior wall of the upper portion of the stomach, while computed tomography (CT) showed no obvious regional lymph node enlargement and distant metastases. The patient subsequently underwent laparoscopic proximal gastrectomy and esophagogastrostomy but developed candidemia on postoperative day 7. On postoperative day 14, endoscopy revealed gastric ischemic changes around the anastomotic site, suggesting that the patient's candidemia developed due to gastric necrosis. His vital signs remained normal, while the gastric remnant ischemia was localized. Given that surgery in the presence of candidemia was considered extremely risky, conservative treatment was elected. A W-ED tube was placed nasally, after which enteral feeding was initiated along with gastrointestinal tract decompression. Although the patient subsequently developed anastomotic leakage due to gastric remnant necrosis, local control was achieved and conservative treatment was continued. On postoperative day 52, healing of the gastric remnant necrosis and anastomotic leakage was confirmed, after which the patient started drinking water. Although balloon dilation was required due to anastomotic stenosis, the patient was able to resume oral intake and was discharged on postoperative day 88. CONCLUSIONS: Herein, we present our experience with a case of gastric remnant necrosis after proximal gastrectomy, wherein conservative management was achieved using a W-ED tube. In cases involving high operative risk, the management should be mindful of gastric remnant necrosis as a post-gastrectomy complication.

Successful resection of a neuroendocrine tumor in the gallbladder: a case report.

BACKGROUND: Gallbladder neuroendocrine tumors (GB-NETs) are extremely rare, representing only 0.5% of all NETs because no neuroectodermal cells are present in the gallbladder. In 2019, the World Health Organization updated the classification of NETs based on their molecular differences. The mutation status of DAXX and ATRX has been added to the criteria for well-differentiated NETs. CASE PRESENTATION: A 50-year-old man presented to our hospital for further examination of a gallbladder polyp. He had no right quadrant pain, fever, jaundice, weight loss, or carcinoid syndrome-related symptoms. The patient hoped to avoid cholecystectomy. During the 3-year observation period, the polyp gradually increased in size from 8.3 to 9.9 mm. He decided to undergo surgery, and whole cholecystectomy was successfully performed. Immunohistochemical staining revealed positivity for chromogranin A, synaptophysin, and CD56. The Ki-67 index was < 3%. Taken together, these results led to a diagnosis of a grade 1 GB-NET. We also performed immunohistochemical staining of DAXX and ATRX, which revealed that DAXX protein expression was negative. The patient's postoperative course was uneventful, and he developed no recurrence for 8 years after surgery. CONCLUSION: We experienced a very rare case of GB-NET. Obtaining a correct preoperative diagnosis is quite difficult at the first evaluation. A GB-NET should be considered as a differential diagnosis of gallbladder tumors.

Visualization of lymphatic flow in laparoscopic colon cancer surgery using indocyanine green fluorescence imaging.

Intraoperative visualization of lymphatic flow could guide surgeons performing laparoscopic colon cancer surgery on the extent of intestinal resection required. The purpose of this study was to investigate indocyanine green fluorescence imaging for intraoperative detection of lymphatic flow and nodes in such patients. All patients undergoing elective laparoscopic surgery for colorectal cancer from October 2016 to July 2017 were included in this study. Indocyanine green was injected submucosally around the tumors via a colonoscope and lymphatic flow assessed with a laparoscopic near-infrared camera system intraoperatively. Lymphatic flow was visualized perioperatively in 43 of 57 patients (75.4%). The rate of visualized lymphatic flow was significantly higher in patients with a lower clinical stage than in those with a higher clinical stage (p = 0.0103). Among the 14 patients in whom lymphatic flow was not visualized, 10 (71.4%) had cStage III or IV cancer. Our results indicate the potential role of intraoperative navigation in colon cancer surgery in early-stage colon cancers. This method allows the surgeon to clearly identify lymphatic flow during surgery and allows the determination and individualization of the lymph node dissection range.

Occult follicular lymphoma in a swollen regional lymph node of gastric schwannoma.

BACKGROUND: Regional lymphadenopathy is more commonly noted in gastric schwannomas than in other gastric submucosal tumors. Most of the swollen lymph nodes associated with gastric schwannomas are non-metastatic lymphadenopathy. CASE PRESENTATION: A 69-year-old Japanese woman was referred to our hospital with a chief complaint of abdominal discomfort. Contrast-enhanced computed tomography (CT) of the abdomen revealed an extraluminal tumor with heterogeneous enhancement at the middle stomach on the lesser curve, accompanied with one swollen lymph node approximately 10 mm in size and several small lymph nodes in the perigastric region. These lymph nodes were flat; therefore, we considered them to be non-metastatic. The main tumor was removed via wedge resection. Soft and slightly swollen lymph nodes, which were compatible with the lymph nodes noted in the preoperative CT, were found near the main tumor in the fatty tissue at the lesser curvature of the stomach. An excisional biopsy of the largest lymph node was performed for the diagnosis. Based on pathological findings, a diagnosis of gastric schwannoma and follicular lymphoma (FL) was confirmed. The patient is doing well without recurrence of either the gastric schwannoma or FL 28 months postsurgery. CONCLUSIONS: The present report detailed an extremely rare case of FL coincidentally discovered in the swollen regional lymph node of gastric schwannoma.

[Right Hemicolectomy and Pancreatoduodenectomy for Transverse Colon Cancer Invasion to the Duodenum-A Case Report].

A 74-year-old woman visited her local doctor with stomach ache and weight loss. Abdominal ultrasonography showed a mass in the hepatic flexure of the transverse colon. She was referred to our hospital. Colonoscopy revealed transverse colon cancer in the hepatic flexure. Upper endoscopy showed redness of the mucosa and stenosis in the descending portion of the duodenum. Therefore, duodenal invasion was suspected. The CT scan showed a regional lymph node metastasis, but there were no obvious signs of distant metastases. From the aforementioned findings, we diagnosed the patient with duodenal invasion of transverse colon cancer(cT4b, N1, M0, cStage Ⅲ). There was no intraoperative peritoneal dissemination or liver metastasis, and we performed right hemicolectomy and pancreatoduodenectomy for transverse colon cancer. On histopathological examination, we diagnosed pT4b(Duo, Pan), N1b(3/35), M0, pStage Ⅲb. The patient had delayed gastric emptying after surgery. She recovered conservatively and was discharged on POD 37. She underwent adjuvant chemotherapy( capecitabine therapy)and has been alive without recurrence 8 months after surgery. In some cases of colon cancer invasion of other organs, long-term survival can be achieved if R0 resection is possible, and we should consider extended resection.

[A Resected Case of Angiomyolipoma Difficult to Be Distinguished from Hepatocellular Carcinoma].

A 42-year-old man complaining of left back pain was admitted to our hospital. The hepatis B and C surface antigens were negative. The serum levels of tumor markers were within the reference ranges. Abdominal ultrasound revealed an 8 cm-sized, primarily round and hyperechoic mass in the left lateral segment. Contrast-echo showed non-uniform enhancement in the arterial phase and uniform enhancement in the portal phase. This mass did not indicate"wash-out"on contrast- enhanced CT. It showed hypointensity in the hepatobiliary phase on MRI. The definitive diagnosis could not be obtained, and the patient was suspected with malignancy, such as hepatocellular carcinoma(HCC). Therefore, left hemi-hepatectomy was performed for the diagnostic treatment. Based on the immunochemical staining results, he was diagnosed with angiomyolipoma( AML). AML is composed of fat, blood vessels, and smooth muscles. It is regarded as a tumor of perivascular epithelioid cell tumor(PEComa). Early venous return and adipose tissues in the tumor were the distinctive features of this tumor. The preoperative diagnosis of AML without any fatty component as in this case is very difficult.