Primary tumours of the greater omentum

Case report: A rare case of omental extrarenal rhabdoid tumor and review of the literature

Extrarenal rhabdoid tumor of the greater omentum is extremely rare, with only sporadic reports and limited documentation of its ultrasonographic findings. Here, we report a case of an extrarenal rhabdoid tumor of the greater omentum in a 16-year-old girl and review the relevant literature. It was found that the disease mainly occurred in female children and adolescents, and mainly manifested as lower abdominal pain and a large abdominal cystic or solid hemorrhagic mass. The clinical characteristics include a high degree of malignancy and mortality. Ultrasound shows some malignant features, but it is not specific; thus, it is easy to be misdiagnosed in the clinic.

Primary omental smooth muscle tumor in an adult male: a diagnostic dilemma for leiomyoma: a case report

BACKGROUND

The greater omentum comprises peritoneal, adipose, vascular, and lymphoid tissues. Most omental malignancies are metastatic tumors, and the incidence of primary tumors is rare. We report on a prior omental smooth muscle tumor case in an adult male patient.

CASE PRESENTATION

A 54-year-old Japanese male patient with no relevant medical history was diagnosed with an abdominal mass during a routine medical checkup. Subsequent contrast-enhanced computed tomography revealed a mass of approximately 3 cm in size in the greater omentum, and a laparotomy was performed. A 27 × 25 × 20 mm raised lesion was found in the omentum. Microscopically, spindle cells were observed and arranged in whorls and fascicles. Individual tumor cells had short spindle-shaped nuclei with slightly increased chromatin and were characterized by a slightly eosinophilic, spindle-shaped cytoplasm. The mitotic count was less than 1 per 50 high-power fields. The tumor cells showed positive immunoreactivity for α smooth muscle actin, HHF35, and desmin on immunohistochemical examination. The Ki-67 labeling index using the average method was 1.76% (261/14806). No immunoreactivity was observed for any of the other tested markers. We considered leiomyoma owing to a lack of malignant findings. However, primary omental leiomyoma has rarely been reported, and it can be difficult to completely rule out the malignant potential of smooth muscle tumors in soft tissues. Our patient was decisively diagnosed with a primary omental smooth muscle tumor considering leiomyoma. Consequently, the patient did not undergo additional adjuvant therapy and was followed up. The patient was satisfied with treatment and showed neither recurrence nor metastasis at the 13-month postoperative follow-up.

DISCUSSION AND CONCLUSION

We encountered a primary smooth muscle tumor of the greater omentum with no histological findings suggestive of malignancy in an adult male patient. However, omental smooth muscle tumors are extremely difficult to define as benign, requiring careful diagnosis. Further case reports with long-term follow-up and case series are required to determine whether a true omental benign smooth muscle tumor (leiomyoma) exists. In addition, proper interpretation of the Ki-67 labeling index should be established. This case study is a foundation for future research.

Diagnostic challenge of a huge omental tumor: A case report

INTRODUCTION

Omental lipomas are rare tumors that are often asymptomatic. They may produce vague abdominal complaints. Radiological diagnosis may be challenging. We report a large omental tumor with pre-operative diagnostic ambiguity due to suspicious radiological appearance.

CASE PRESENTATION

A 61-year-old man presented to the emergency department with abdominal pain. Upon investigation, computed tomography and magnetic resonance imaging showed a large predominantly fatty omental tumor that was suspicious of liposarcoma. The patient underwent laparotomy with excision of a huge 5706-g tumor. The final diagnosis of lipoma was made histopathologically.

DISCUSSION

Although most omental lipomas are diagnosed by cross sectional imaging, radiological features may be confused with that of a liposarcoma. Pre-operative biopsy confirmation can be considered but is associated with the risk of complications and seeding. Surgical excision serves as a diagnostic and therapeutic modality, and can be achieved by open or laparoscopic approaches guided by tumor size.

CONCLUSION

Omental lipomas are rare and most commonly asymptomatic until achieving a sizable mass. In such cases, the diagnosis can be challenging due to the possible confusion with liposarcoma, which may affect the management plan.

Histopathological Evaluation and Molecular Diagnostic Tests for Peritoneal Metastases with Unknown Primary Site-a Review

Cancer of unknown primary (CUP) is a well-studied entity with guidelines available for the management of patients with CUP. The peritoneum represents one of the metastatic sites in CUP, and peritoneal metastases (PM) could present as CUP. PM of unknown origin remains a poorly studied clinical entity. There is only one series of 15 cases, one population-based study, and few other case reports on this subject. Studies on CUP, in general, cover some common tumour histological types like adenocarcinomas and squamous carcinomas. Some of these tumours may have a good prognosis though majority have high-grade disease with a poor long-term outcome. Some of the histological tumour types commonly seen in the clinical scenario of PM like mucinous carcinoma have not been studied. In this review, we divide PM into five histological types-adenocarcinomas, serous carcinomas, mucinous carcinomas, sarcomas and other rare varieties. We provide algorithms to identify the primary tumour site using immunohistochemistry when imaging, and endoscopy fails to establish the primary tumour site. The role of molecular diagnostic tests for PM or unknown origin is also discussed. Current literature on site-specific systemic therapy based on gene expression profiling does not show a clear benefit of this approach over empirical systemic therapies.

A 3D multi-cellular tissue model of the human omentum to study the formation of ovarian cancer metastasis

Reliable and predictive experimental models are urgently needed to study metastatic mechanisms of ovarian cancer cells in the omentum. Although models for ovarian cancer cell adhesion and invasion were previously investigated, the lack of certain omental cell types, which influence the metastatic behavior of cancer cells, limits the application of these tissue models. Here, we describe a 3D multi-cellular human omentum tissue model, which considers the spatial arrangement of five omental cell types. Reproducible tissue models were fabricated combining permeable cell culture inserts and bioprinting technology to mimic metastatic processes of immortalized and patient-derived ovarian cancer cells. The implementation of an endothelial barrier further allowed studying the interaction between cancer and endothelial cells during hematogenous dissemination and the impact of chemotherapeutic drugs. This proof-of-concept study may serve as a platform for patient-specific investigations in personalized oncology in the future.

Giant omental lipoma, a rare etiology of right-iliac fossa pain in adult: A surgical case report

BACKGROUND

Omental lipoma is an uncommon abdominal tumor of mature fat cells. Those benign tumors are usually asymptomatic but occasionally can cause signs and symptoms based on their location, size, and presence of complications. Radiological investigations such as Abdominal ultrasonography (USG) and computed tomography (CT) are crucial to evaluate and diagnose intra-abdominal tumors, especially omental lipomas.

PRESENTATION

A 61-year-old male patient presented to our hospital with right iliac fossa pain. Physical examination and laboratory test results were normal. The performed abdominal CT scan revealed a large right-sided intraperitoneal mass measuring about 2.4 × 10 × 20 cm. Then, an ultrasound-guided biopsy was done and the picture was most consistent with lipoma. So, surgical intervention was decided and omental lipoma was completely exteriorized via a laparoscopic approach. The weight of the excised omental mass was 2.45 kg, measuring 23 × 18 × 7 cm. The resected specimens, including omental lipoma and omental lymph nodes, were sent for histopathological studies. The postoperative period was uneventful.

DISCUSSION

Omental lipoma is an unusual entity that occurs often in children and rarely in adults. The clinical features of omental lipomas include abdominal discomfort, abdominal lump, abdominal pain, nausea, and/or weight loss. Diagnosis of the omental lipoma relies on imaging and physical examination, which was normal in the presented case. Abdominal CT provides definitive fat content characterization and its localization within the omentum.

CONCLUSION

Due to the rare etiologic origin of omental lipomas, we report the case of a 61-year-old male with right iliac fossa pain, found to be caused by detected giant omental lipoma.

Primary Pleomorphic Omental Rhabdomyosarcoma in an Adult: A Report of a Unique Case

Rhabdomyosarcoma (RMS) is a very rare, highly malignant neoplasm thought to originate from the pluripotent mesenchymal tissue. Predominantly diagnosed among children and teenagers, however they can also be encountered in adults. There are a few risk factors associated with RMS like family history of malignancy and genetic syndromes like neurofibromatosis type 1, Li-Fraumeni syndrome, Noonan syndrome and Beckwith-Wiedemann syndrome; however, most cases of RMS are sporadic. Other factors like radiotherapy for other malignancy and pre-natal radiation exposure also are associated with increased risk of developing RMS. The most common reported sites for RMS are head, neck, trunk, pelvis and lower limbs. Omental involvement of primary RMS has been rarely reported in the literature. Principally, the survival of treated RMS cases has improved, primarily due to multidisciplinary management approaches. In this paper, we report a case of primary pleomorphic RMS in a 50-year-old female who presented with abdominal pain.

Giant Mesenteric Lipoma in an Adult

Lipomas are benign mesenchymal tumors of mature adipocytes and commonly occur in the upper trunk. Mesenteric lipomas are relatively rare tumors of the gastrointestinal system. They are usually asymptomatic, detected incidentally on abdominal imaging, or can present with variable symptoms depending on the location, size, and rapidity of tumor growth. The ileal mesentery is the most common site, occurring in adults ranging from 40 to 60 years. We present the case of an unusually large mesenteric lipoma in an adult male patient who presented with vague abdominal pain.

IS A BIG OMENTUM THE SURGEON'S BEST FRIEND OR WORST ENEMY? REVIEW

The interest of surgeons in the greater omentum is associated with a unique combination of such functions as plasticity, immune defense, barrier, hormonal, angiogenesis and regeneration for adjacent tissues, reabsorption, hemostatic, thermoregulation. The purpose of this review was to track the historically changing position of operations with the use of the greater omentum in abdominal, thoracic surgery, reconstructive plastic surgery, analyze the aspects of the use and controversial issues of omentization of the anastomoses line and omentoplasty in modern conditions, as well as highlight promising directions for the use of the greater omentum in medicine. in the sources of domestic and foreign databases until July 2021. Information about the negative consequences of omentectomy is given – a decrease in local and general immunoresistance, the development of adhesive disease, an increase in the number of postoperative purulent-inflammatory complications. It is useful for the surgeon to use a large omentum in non-standard and technically difficult cases. Situations are described in which a radical attitude to the greater omentum is justified – torsion of the omentum strand, metastasis, adhesions, omentitis, entrapment in hernias, complications from the pedicle flap. Analysis of the literature revealed ambiguous results of omentization and omentoplasty, which indicates the need for randomized studies in this area, the development of clinical recommendations for these operations with a description of clear indications and methods of carrying out. 

Recurrence of Adult Granulosa Cell Tumor in the Greater Omentum 11 Years after Surgery

Adult-type ovarian granulosa cell tumors (AGCTs) are very rare tumors that account for <5% of all ovarian carcinomas. AGCTs have low malignancy potential and rarely metastasize 5-30 years after the initial diagnosis. Because time has passed from the first surgery and because recurrence develops in various locations, the differential diagnosis is difficult. In particular, tumors developing in the greater omentum are encountered rarely, and it is necessary to carefully consider the differential diagnosis, including primary and secondary neoplasms. Although CT is useful to detect omental tumors, the diagnosis requires invasive procedures. We report a case of AGCT recurrence in the greater omentum that was resected during laparoscopic cholecystectomy. A patient visited our hospital with right-sided abdominal pain. The CT revealed gallbladder stones, a ureteral stone, and a right abdominal mass. The diagnosis of the abdominal tumor was difficult on the basis of blood biochemical testing, gastrointestinal endoscopy, or image inspection. Although the patient underwent several previous surgeries and there were no findings of malignancy with positron emission tomography, we chose to resect the tumor for combined diagnosis and treatment during laparoscopic cholecystectomy. Intraoperative findings showed that the tumor originated from the greater omentum, and the tumor was diagnosed as AGCT recurrence by pathology. A recurrence of AGCT in the greater omentum is very rare, and laparoscopic surgery was safe and useful for resection, in our case.

Omental mass combined with indirect inguinal hernia leads to a scrotal mass: A case report

BACKGROUND

Primary omental tumors are uncommon, and omental fibromas account for 2% of these tumors. Due to the low incidence of omental fibromas and the limited relevant literature, it is challenging for clinicians to make an accurate diagnosis of this condition, especially before surgery.

CASE SUMMARY

A 30-year-old man was admitted to the hospital because of a left epididymal mass with vague discomfort for more than 1 mo. A physical examination was performed, and the findings showed that the epididymal mass may have entered the abdominal cavity. Pelvic computed tomography was performed in our hospital and revealed a left inguinal hernia with a mass in the hernial contents, and no masses were found in the left epididymis. A traditional inguinal hernia incision was made. Intraoperative hernia contents were found to be of the greater omentum, and a 2.5 cm-diameter mass was found at the distal end of the greater omentum. The scrotum and epididymis did not exhibit other masses. Then, the mass of the greater omentum was excised. Intraoperative frozen pathological examination suggested a spindle cell tumor. The postoperative pathological examination suggested that the mass was an omental angiofibroma. Postoperatively, the patient recovered well and was discharged. Outpatient re-examinations were performed at 1 mo and half a year after the operation and showed no obvious abnormalities.

CONCLUSION

Due to the low morbidity rate associated with and latent nature of omental tumors, these tumors are difficult to diagnose preoperatively; thorough medical history taking, detailed physical examinations, and necessary imaging auxiliary examinations can help clinicians diagnose and treat these cases.

Large benign schwannoma of the greater omentum with synchronous cervical cancer: A case report

Introduction and importance

Schwannomas are uncommon tumors of the omentum with only 16 reported cases originating from the greater omentum in the literature. We report for the first time a synchronous presentation of an omental schwannoma and cervical cancer.

Case presentation

A 37-year-old female presented with an abdominal mass and heavy vaginal bleeding. An 11.5 × 14.6 × 16.6 cm complex omental mass and 5.4 × 6.2 × 4.4 cm lobulated heterogeneous cervical mass were noted on CT-scan. Wide excision of the complex mass and radical hysterectomy with bilateral salpingo-oophorectomy and pelvic lymph node dissection was performed. The final biopsy revealed benign omental schwannoma and poorly differentiated cervical adenocarcinoma.

Clinical discussion

Schwannomas originating from the greater omentum are less common than in the lesser omentum due to the paucity of nervous tissue in the former. They can undergo malignant transformation and the most common presentation is abdominal pain/discomfort. Larger tumors may cause catastrophic bleeding. Prompt surgery should be offered and wide local excision with sufficient margins be performed when there is suspicion of malignancy. Schwannomas presenting with multiple or synchronous lesions are commonly associated with neurofibromatosis type 2, schwannomatosis, and Carney's complex. Whether this co-occurrence is simply incidental or has a causal relationship remains to be established.

Conclusion

Benign schwannoma of the greater omentum is rare and only requires complete tumor excision. However, surgeons should be aware that synchronous presentation of cervical cancer is possible and that thorough examination of both sites should be undertaken when either primary tumor presents.

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Schwannoma of the greater omentum is rare with only 16 reported cases in the literature.

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Prompt surgery should be offered because of the possibility of tumor bleeding and malignancy.

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Complete tumor excision is adequate for benign lesions.

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Synchronous presentation of cervical cancer is possible.

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Thorough clinical examination of the omentum or cervix is prudent when either primary tumor presents solely.

Resection of liposarcoma of the greater omentum: A case report and literature review

INTRODUCTION

Liposarcoma usually occurs in the retroperitoneum and limbs. Liposarcoma of the greater omentum is rare, and most information of such liposarcomas has come from case reports.

PRESENTATION OF CASE

A 60-year-old woman was found to have an 8-cm intra-abdominal mass (suspected lipoma) by computed tomography. At the age of 63 years, she underwent a medical examination and a mass was palpated in the abdomen. Contrast-enhanced computed tomography and magnetic resonance imaging confirmed the presence of a huge intra-abdominal tumor with the omental artery passing through the mass. The tumor was simply resected. Histopathologically, the tumor was diagnosed as a well-differentiated liposarcoma, and the resection margin was microscopically negative. The patient had developed no recurrence or complications 9 months postoperatively.

DISCUSSION

Liposarcoma of the greater omentum is rare, and differentiation of liposarcoma from other tumors is challenging. Adjuvant therapy has not been established as an effective treatment, and radical (R0) resection of the tumor is recommended. Our case of liposarcoma of the greater omentum was surgically managed with good outcomes.

CONCLUSION

The diagnosis of liposarcoma with a lipomatous tumor is challenging, and resection should be considered for huge intra-abdominal lipomatous tumors.

Trans Arterial Embolization of Spontaneous Intra-Abdominal Haemorrhage from Omental Lipoma

We describe 3 cases of omental lipoma of whom 2 presented with symptomatic haemorrhage. Notably the haemorrhage in the 2 reported cases was from foregut arteries. Thorough knowledge of anatomy and embryology is critical in identifying the source of haemorrhage and differentiating this condition from other common causes of mesenteric haemorrhage. To the best of our knowledge, this is the first case series reporting this uncommon cause for abdominal haemorrhage. The successful management of this condition using superselective embolization is discussed. Clinicians need to exercise diligence and caution in omental lipomas presenting with spontaneous haemorrhage and this notion is exemplified in our reported cases.

A rare case of perivascular epithelioid cell tumor (PEComa) of the greater omentum

Background

A tumor composed exclusively or predominantly of human melanin black 45 (HMB45)-positive epithelioid cells is called a perivascular epithelioid cell tumor (PEComa). We report a very rare case of a PEComa of the greater omentum.

Case presentation

MRI conducted to examine the orthopedic disease of the patients, a 49-year-old Japanese woman, also identified a tumor in her pelvis. A CT scan revealed a tumor mass on the right side of the pelvic floor and clear nutrient vessels originating from the splenic and celiac arteries. An omental primary tumor or accessory spleen was thus suspected, and tumor resection was performed. The tumor was a light brown solid tumor with a smooth margin, measuring 5.2 × 3.8 × 3.5 cm. Histopathologically, the tumor was composed mainly of spindle and epithelioid cells, and large and small blood vessel formation was observed. In the immunohistochemical staining, tumor cells were positive for human melanin black 45 (HMB-45) and Melan-A and partially positive for alpha-smooth muscle actin. The final diagnosis was PEComa of the greater omentum.

Conclusions

Although omental PEComa is very rare, it should be considered as a differential disease of an omental primary tumor.

An omental fibroma resembling a testicular tumour but presented as an irreducible inguinal hernia

We present a case of omental fibroma, which posed a surgical diagnostic dilemma. Primary tumours of the omentum are uncommon, and omental fibromas account for 2% of these. The rarity of omental fibroma and paucity of available information hamper an accurate diagnosis. In this particular case, the diagnostic process was misleading. The history was classical of an irreducible inguinal hernia, but the physical examination and imaging studies were suggestive of a testicular tumour. However, intraoperatively, an omental tumour and a normal testicle were found in the scrotum. Histopathological examination proved the tumour to be a fibroma. The presentation of an omental fibroma in an inguinal hernia sac had never been reported in literature. Due to the rarity of such cases, a thorough history, detailed examination, and objective investigation are the pillars to attain the correct diagnosis.

Primary leiomyosarcoma of the greater omentum: a case report

INTRODUCTION

Greater omentum leiomyosarcomas are rare tumors with only a few cases reported in literature.

PRESENTATION OF CASE

We report the case of a 68-year-old man who consulted complaining of diffuse abdominal pain without a palpable mass at physical examination. Imaging studies revealed a solid-cystic lesion in the right lower quadrant. Surgical resection was performed and the tumor was diagnosed as a leiomyoscarcoma by histological and immunohistochemical examinations.

DISCUSSION

Surgical resection of all lesions seems to be a reasonable therapeutic approach if resection is feasible. Chemotherapy may be used in selected cases.

CONCLUSION

More cases are needed to define the best treatment approach of this disease.

Primary leiomyosarcoma of the omentum presenting as an ovarian carcinoma, case report and review of the literature

Primary omental leiomyosarcoma is a rare tumor. We report a case of successfully resected omental leiomyosarcoma whose presentation mimicked ovarian carcinoma. Symptoms of abdominal distension and discomfort that lasted 8 months followed by pain lead to a diagnosis of a large mass in the abdomen. Physical examination revealed a large, over 20 cm tumor, suspected to be of ovarian origin. A small amount of ascites was found on Computerized Tomography (CT) and ultrasound (US) scans. Total abdominal hysterectomy with bilateral salpingo-oophorectomy, omentectomy and tumor debulking procedure was planned. Laparotomy revealed normal uterus ovaries and tubes with a leiomyosarcoma of the omentum which was completely resected successfully. Only 26 cases of primary leiomyosarcoma of the omentum were previously described in the literature. A review of the literature is also presented.

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Primary leiomyosarcoma of the omentum can mimic the presentation of an ovarian carcinoma.

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The diagnosis is based mostly on the appearance on Computerized Tomography scan and angiography.

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Complete surgical resection of this tumor can lead to long term survival.

Childhood giant omental and mesenteric lipoma

Omental and mesenteric lipomas are very rare benign lesions of mature adipose tissue. They are well-defined, noninvasive, and encapsulated masses that can be discovered in asymptomatic patients or may cause variable nonspecific symptoms depending on their size and location. The omental and mesenteric lipoma has confusing features in ultrasound; however, computed tomography and magnetic resonance imaging can well characterize and demarcate these lesions. Though few cases of mesenteric and omental lipomas have been reported in the literature, but because of its large size and childhood presentation, the case we present, can be one of the largest childhood omental and mesenteric lipomas ever reported. A 6-year-old girl presented with slowly progressing abdominal distension and repeated dull abdominal pain for last 4 years. Abdominal and pelvic computed tomography examination revealed a huge mesenteric and omental lipoma that was resected surgically without any complications.

Omental rhabdomyosarcoma (primary rhabdoid tumor of greater omentum): a rare case report

The greater omentum is an uncommon location for primary tumors. Metastatic tumors of the omentum are common. In contrast, primary tumors of the omentum are very rare. Sporadic cases of primary rhabdomyosarcoma (RMS) arising in the abdomen have been reported, but these cases are limited almost exclusively to the pediatric population. We report a well-documented case of primary intra-abdominal RMS in a 21-year-old man who presented with complaints of abdominal pain and lump in left hypochondrium region. Imaging revealed it to be a large mass in the left hypochondrium region displacing the bowel loops. Further investigations revealed omental RMS. The mass had originated from the greater omentum and was excised. Our case is doing well and is presently receiving chemotherapy.

Laparoscopic resection for torsion of an omental lipoma presenting as an acute abdomen in a 5-year-old girl

Primary tumors of the greater omentum are rare. We report a case of a 5-year-old girl presenting with an acute abdomen who had omental torsion caused by a giant lipoma of the greater omentum, which was diagnosed by a computed tomography scan. Laparoscopy revealed a yellow tumor of the greater omentum with a smooth surface. Tumor excision and partial omentectomy was performed to treat the torsion, and the tumor was retrieved through a 4-cm-wide abdominal incision. Macroscopically, the specimen was 80 × 60 × 25 mm in size and 74.8 g in weight, and histopathological findings were consistent with the diagnosis of lipoma. The present case highlights the possible use of laparoscopic surgery for removing large abdominal lipomas, thus avoiding the drawbacks of laparotomy in terms of postoperative pain and prolonged hospital stay.

Primary malignant rhabdoid tumor of greater omentum in 10-year-old girl

Contrary to metastatic tumors of the omentum, primary tumors of the omentum are very rare. A 10-year-old girl presented with low abdominal pain. Imaging studies showed a multiseptated hemorrhagic tumor. The mass from the omentum was removed completely and confirmed as a malignant rhabdoid tumor. Despite aggressive chemotherapy, she died after 9 months due to disease progression. We report one case of primary malignant rhabdoid tumor of the omentum for the first time.

Leiomyoma of the greater omentum presenting with massive ascites

INTRODUCTION

: Primary tumours of the omentum are quite uncommon, although it is a common site for for secondaries.

PRESENTATION OF CASE

: We report a case of leiomyoma of the greater omentum in a 31-year-old nulliparous woman who presented with a 2-year history of progressive abdominal distension with examination findings of massive ascites and a mobile ill-defined centrally located intra-abdominal mass. The preoperative diagnosis was equivocal. At surgery a pedunculated greater omental mass, which was histologically reported as a leiomyoma, was seen. She had an uneventful post-operative recovery. She has been followed up for twelve months with no evidence of recurrence or residual disease.

DISCUSSION

: Extra-uterine leiomyoma is rare. It is even rarer for it to originate from the omentum. Pre-operative diagnosis is challenging. To the best of our knowledge this is the first reported case of leiomyoma of the omentum in Nigeria.

CONCLUSION

: The uncommon association of ascites with this tumour deserves further scrutiny. The patient is still being followed-up.

Primary omental pleomorphic liposarcoma identified at autopsy in a living donor kidney transplant recipient

Metastatic and recurrent tumors of the omentum are common, but primary omental pleomorphic liposarcoma (POPL) is an extremely rare type of solid omental tumor. We describe the case of a patient with POPL who received a renal transplant from a living donor. Despite good allograft function, the volume of peritoneal fluid gradually increased. An exploratory laparotomy could not be performed because the patient was obese and developed hemodynamic instability. Therefore, a shunt was placed between the peritoneal cavity and the internal jugular vein using the Denver^® shunt system; however, the patient died of respiratory insufficiency. On the basis of the autopsy results, we diagnosed the patient's condition as POPL. We speculated that the malignancy did not originate directly from the donor cells. We report POPL in a living donor renal transplant recipient.

Omental vascular pedicle sign: multidetector CT finding useful for diagnosis of an omental mass

OBJECTIVE

To describe multidetector CT findings of "omental vascular pedicle" sign.

MATERIALS AND METHODS

"Omental vascular pedicle" sign was defined as dilated omental vein associated with a mass located in omentum and was observed in 7 patients (5 women, 2 men). Mean age was 45 years. CT examinations and patient records were retrospectively reviewed. CT images were obtained by 16-MDCT (n = 1) and 64-dual source MDCT (n = 6). Curved planar and volume rendered images were reconstructed from axial images. Diameter of omental vein and drainage site were recorded. Images were evaluated by 2 radiologists in consensus.

RESULTS

Pathologic diagnosis of patients with "omental vascular pedicle sign" was omental angiosarcoma (n = 1), endometrial adenocarcinoma (n = 2), ovarian serous adenocarcinoma (n = 2), mixed gonadal tumor (n = 1), malignant peripheral sheath tumor (n = 1). In 5 patients, omental vein drained into splenic vein and in 2 patients it drained into right gastroepiploic vein. Mean size of omental masses associated with omental vascular pedicle was 7.1 × 4.5 cm (range 15 × 11 cm to 2.7 × 1.6 cm). Mean diameter of omental vein was 3.1mm (range 6-1.5mm). Diameter of the omental vein increased with the increasing size of omental masses and Pearson's correlation coefficient was 0.99.

CONCLUSION

"Omental vascular pedicle sign" can be helpful to objectively diagnose omental masses in patients with primary and metastatic omental tumors.

Indirect hernial sac containing the uterus, ovary, and fallopian tube in association with a giant intraabdominal lipoma: report of a case

Presence of the ovary, fallopian tube, and uterus within an inguinal hernia is a rare condition. In this report, we describe the case of a 47-year-old female, multiparous patient with a giant omental lipoma (18 × 8 × 7 cm, 422 g) and left inguinal hernia. The uterus, left ovary, and fallopian tube were in the hernial sac. The presence of the uterus within the hernial sac accompanies mullerian anomalies, although, in this case, there was no such anomaly. To our knowledge, there have been no cases in the literature of a giant intraabdominal lipoma and a hernial sac containing the uterus, ovary, and fallopian tube, but a few cases of inguinal hernia involving the ovary, fallopian tube, and uterus have been reported. The aim of this case report was to call attention to the observation that the inguinal hernia seen in female patients may involve the ovary, fallopian tube, and uterus.

Malignant fibrous histiocytoma arising from the omentum presenting as hemoperitoneum

Malignant fibrous histiocytoma (MFH) is an uncommon soft-tissue sarcoma that occurs primarily in the extremities and rarely involves the retroperitoneum and abdomen. A 63-year-old man was admitted to the emergency room because of epigastric pain. Computed tomography revealed a large heterogeneous enhanced mass originating from the omentum with hemoperitoneum. The patient underwent laparoscopic omental mass excision and hematoma evacuation. Histological examination of the resected tumor revealed MFH. This case was therefore omental MFH presenting with hemoperitoneum.

Fibroma of the omentum resembling an ovarian tumor in the pelvis

We would like to report the case of a patient with fibroma of the omentum that resembled an ovarian tumor in the pelvis. Since primary tumours of the omentum are rare, there is a paucity of information about the biology of such tumors in the basic texts and literature. An ultrasound examination of the patient revealed a mass, likely of ovarian origin, which consisted of liquid and solid components. It was suspected to be a malignant ovarian tumor. However, laparotomy demonstrated it was an omental tumor. This case shows that it can be difficult to pre-operatively diagnose omental fibromas because of their close resemblance to ovarian tumors.

Pseudotumor of the omentum with a fishbone nucleus

A 23-year-old Japanese man was admitted with a chief complaint of abdominal pain. He was previously healthy, and his past medical history was unremarkable. Local tenderness and rebound tenderness at McBurney's point were elicited. Abdominal roentgenography was non-diagnostic. Ultrasonography and computed tomography showed a tumor with a central core. Based on a diagnosis of appendicitis with omental inflammation or an omental tumor, laparotomy performed. Intraoperatively, no site of gastrointestinal perforation was detected; however, a 5-cm omental granuloma was identified that proved to have a fishbone nucleus on pathological examination. The postoperative course was uneventful, and upper gastrointestinal endoscopy and barium enema were unremarkable. A large solitary omental pseudotumor is rare, and the clinical course in this case was atypical compared with the usual course of intestinal perforation by a foreign body and formation of an intra-abdominal granuloma.

Torsion of an omental lipoma presenting as an emergency

Primary omental pathology is rare. A case of torsion of an omental lipoma is reported in a 77-year-old women presenting as an emergency with lower abdominal pain. Abdominal and pelvic CT scan was of value in the pre-operative investigation.

Le péritoine acteur de la pathologie abdominale

The peritoneum is an important actor in diseases of the abdomen: defects of the peritoneum or mesos may lead to internal hernias; developmental anomalies of the peritoneum may lead to volvulus and bowel obstruction; diffuse or localized primary or secondary tumors of the peritoneum may develop; infectious, inflammatory or ischemic primary diseases of the peritoneum may cause abdominal pain, sepsis or result in the formation of fluid collections. The purpose of this presentation is to illustrate the role of imaging in the diagnosis of these different diseases and to provide some guidelines allowing their detection and characterization.