Distinct Indications for Adjuvant Therapy in Resected Invasive Mucinous Cystic Neoplasms of the Pancreas Compared with Pancreatic Ductal Adenocarcinoma.

BACKGROUND: Surgical and adjuvant management of mucinous cystic neoplasms (MCNs) lacks formal guidelines and data is limited to institutional studies. Factors associated with receipt of adjuvant therapy and any associated impact on survival remain to be clarified. In the absence of other data, guidelines that recommend adjuvant chemotherapy for invasive pancreatic adenocarcinoma have been extrapolated to MCN. PATIENTS AND METHODS: The National Cancer Database (2004-2019) was utilized to identify all patients that underwent pancreatic resection for invasive MCNs. Patients that received neoadjuvant therapy or did not undergo lymphadenectomy were excluded. Patient, tumor, and treatment factors associated with survival were assessed. RESULTS: For 161 patients with invasive MCN, median overall survival (OS) was 133 months and 45% of patients received adjuvant therapy. Multivariable analysis demonstrated that poorly differentiated tumors [odds ratio (OR) 4.19, 95% confidence interval (CI) 1.47-11.98; p = 0.008] and positive lymph node status (OR 2.67, 95% CI 1.02-6.98; p = 0.042) were independent predictors of receiving adjuvant therapy. Lymph node positivity [hazard ratio (HR) 2.90, 95% CI 1.47-5.73; p = 0.002], positive margins (HR 5.28, 95% CI 2.28-12.27; p < 0.001), and stage III disease (HR 12.46, 95% CI 1.40-111.05; p = 0.024) were associated with worse OS. Receipt of adjuvant systemic therapy was independently associated with decreased risk of mortality in node positive patients (HR 0.23, 95% CI 0.10-0.69; p = 0.002). Survival was not associated with adjuvant therapy in patients with negative lymph nodes or margin negative status. CONCLUSION: In contrast to pancreatic ductal adenocarcinoma (PDAC), where adjuvant therapy improves OS for every tumor stage, surgery alone for invasive MCN is not associated with improved OS compared with surgery plus adjuvant therapy in node-negative patients. Surgery alone is likely sufficient for a subset of invasive MCN.

Mucinous cystadenocarcinoma of the breast harbours TRPS1 expressions and PIK3CA alterations.

AIMS: Breast mucinous cystadenocarcinoma (BMCA) is a rare tumour recently recognised as a distinct entity by the World Health Organisation Tumour Classification Series. BMCA is a triple-negative tumour that lacks specific immunohistochemical markers; therefore, distinguishing it from mimickers such as ovarian and pancreatic cystadenocarcinomas requires careful clinicopathological correlation. Due to its rarity, little is known about the molecular alterations that underlie BMCA. METHODS AND RESULTS: In this study, we used immunohistochemical staining methods to investigate TRPS1 (trichorhinophalangeal syndrome type 1) expression in BMCA and compare it to expression in ovarian and pancreatic mucinous cystadenocarcinomas. We also collected tumour samples from three BMCA patients for molecular analysis by MALDI-TOF mass spectrometry, real-time polymerase chain reaction, whole exome sequencing and fluorescence in-situ hybridisation. TRPS1 immunoreactivity was found only in BMCA tumour cells and not in the ovarian and pancreatic counterparts. One of the three BMCA tumours also showed a PIK3CA hot-spot mutation, which was confirmed by whole genome next-generation sequencing (NGS). No KRAS, NRAS, BRAF or AKT mutations were found. CONCLUSIONS: To our knowledge, this is the first demonstration of TRPS1 expression in BMCA patients and the first identification of a PIK3CA hotspot mutation in these tumours. These findings provide insights into the molecular mechanisms underlying BMCA tumorigenesis and suggest a potential drug target for this rare and poorly understood cancer.

Primary mucinous tumors of the renal pelvis: Clinical, histopathological, and molecular analysis of three cases.

Primary mucinous tumors of the renal pelvis are extremely rare and pose challenges in terms of diagnosis and treatment. This study reviewed the clinical and pathological characteristics of mucinous tumors of the renal pelvis, including mucinous cystadenocarcinomas and mucinous cystadenomas. Immunohistochemical analysis was conducted in three cases, along with KRAS gene detection using the Amplification Refractory Mutation System (ARMS) method. The results revealed mucinous epithelium with acellular mucinous pools in all cases, and acellular mucinous pools were observed in the renal parenchyma and perirenal fat capsules. All tumors expressed CK20 and CDX2, and one case showed KRAS gene mutation. The study suggests that mucinous cystadenomas of the renal pelvis may exhibit borderline biological behaviors. This study is the first to report a KRAS gene mutation in a mucinous cystadenoma of the renal pelvis, offering valuable insights into the diagnosis and treatment of this rare condition.

Mucinous cystadenocarcinoma of the ovary in a 14-year-old girl: a case report and literature review.

BACKGROUND: Ovarian epithelial tumors are common in adults, and their peak incidence of onset is over 40 years of age. In children, most ovarian tumors are germ cell-derived, whereas epithelial tumors are rare and mostly benign. CASE PRESENTATION: This report describes a case of a 14-year-old Chinese girl with ovarian mucinous cystadenocarcinoma. She was admitted with a small amount of bloody vaginal discharge during the past month. Magnetic resonance imaging of the abdomen and pelvis showed a large solid cystic mass lesion in the left ovary. Tumor marker levels were within normal limits ( CA-125: 22.3 U/mL, HE4: 28.5 pmol/L, HCG: < 1.20 mIU/ml, AFP: 3.3 ng/ml, CEA: 2.2 ng/ml, CA19-9: < 2.0 U/mL). Laparoscopic exploration revealed a large left ovarian tumor. The patient underwent left salpingo-oophorectomy, and showed no significant issues during follow-up, as well as no evidence of recurrence or metastasis. CONCLUSIONS: We report the first pediatric case of ovarian mucinous cystadenocarcinoma in China. Given the scarcity of reports addressing the clinical management of this condition, the present study provides a useful contribution to its further understanding in light of developing future treatment strategies.

[A Case of Radical Resection of Mucinous Cystadenocarcinoma of the Appendix by Laparoscopic Partial Cecal Resection].

A 70-year-old man was admitted to our hospital with a chief complaint of right lower abdominal pain during defecation. The contrast-enhanced CT scan showed a highly expanded appendix, so we suspected an appendiceal mucinous neoplasm, but the diagnosis did not clearly suggest cancer. So, we decided to perform laparoscopic surgery. Based on the intraoperative findings, it was considered that radical resection may be possible by partial cecal resection, and the patient underwent the procedure. Mucinous adenocarcinoma(MACA)was revealed by the postoperative pathological diagnosis. However, because the histological type was G1(well-differentiated)and no metastasis to regional lymph nodes(No. 201)was observed, we decided not to perform an additional ileocecal resection with LN dissection. The patient had a good postoperative course and was discharged from the hospital on postoperative day 4. The patient is still alive, 9 months postoperatively, with no recurrence.

[A Case of Giant Pancreatic Mucinous Cystic Neoplasm That Was Difficult to Preoperative Diagnosis].

A 43-year-old woman with about abdominal distension was referred to our hospital for a more detailed examination. Abdominal CT showed 27 cm-sized cystic lesion with the calcification along the partition wall and a nodular hyperplasia. We suspected pancreatic pseudocyst, primary retroperitoneal tumor and we performed tumorectomy. The resected specimen had a maximum diameter of 27 cm. The histopathological diagnosis was mucinous cystadenocarcinoma of the pancreas with ovarian-type stroma. The adjuvant chemotherapy treated with gemcitabine was selected for 3 courses. She continues to do well without any recurrences 7 months later.

[A Case Report of Psoas Abscess Formation Caused by Mucinous Cystadenocarcinoma].

We report a rare case of psoas abscess formation caused by mucinous cystadenocarcinoma. A 65-year-old women was admitted to our hospital for treatment for iliopsoas abscess. She presented with standing difficulty and her laboratory data showed an increased level of leukocytes. CT scan demonstrated an abscess formation in iliopsoas muscle. Colonoscopy showed an ulcer on her cecum. Although percutaneous drainage was performed on the first day, the abscess relapsed repeatedly. Ileocolectomy was performed on post admission day 29. Abscess drainage continued after the operation, the patient was discharged on postoperative day 34. Pathological examination revealed mucinous cystadenocarcinoma on the cecal tumor. Total 8 cycles of FOLFOX6 was performed as adjuvant chemotherapy. The patient has been survived for 20 months with no recurrence.

Actual malignancy risk of either operated or non-operated presumed mucinous cystic neoplasms of the pancreas under surveillance.

BACKGROUND: Despite the low malignant potential of pancreatic mucinous cystic neoplasms (MCNs), surgery is still performed. The aim of this pragmatic study was to assess the outcome of surgery and surveillance for patients presenting with a presumed MCN at the first evaluation. METHODS: Data for patients with a presumed MCN observed from 2000 to 2016 at the Verona Pancreas Institute and San Raffaele Hospital were extracted from prospective databases. The endpoints were risk of malignancy at pathology and rate of misdiagnosis for the surgical series, expressed as an odds ratio (OR) with 95 per cent confidence interval, and disease-specific survival (DSS) for the surveillance cohort investigated by the Kaplan-Meier method. RESULTS: A total of 424 patients were identified. In the surgical series (229 patients), the rate of misdiagnosis was 19.2 per cent. The rate of malignant MCNs was 10.9 per cent (25 patients). The overall rate of malignancy, including misdiagnoses, was 11.3 per cent (26 patients). Predictors of malignancy were mural nodules (OR 27.75, 95 per cent c.i. 4.44-173.61; P < 0.001), size at least 50 mm (OR 13.39, 2.01 to 89.47; P = 0.007), and carbohydrate antigen 19.9 level (OR 3.98, 1.19 to 13.30; P = 0.025). In the absence of mural nodules and enhancing walls, none of the resected presumed MCNs smaller than 50 mm were malignant. Only patients with high-risk stigmata undergoing surgery experienced a significantly reduced 5-year DSS compared with all other patients (88 versus 100 per cent; P = 0.031). CONCLUSION: Presumed MCNs with mural nodules, enhancing walls or cysts of 50 mm or larger should be considered for upfront surgical resection owing to the high risk of malignancy. In the absence of these features, the incidence of malignancy is negligible, favouring surveillance in selected patients given the low risk of malignancy and the high rate of misdiagnosis. LAY SUMMARY: Malignant degeneration of presumed pancreatic mucinous cystic neoplasms takes several years, if it occurs at all. Mural nodules, enhancing walls or cysts of 50 mm or larger call for surgical resection owing to an increased risk of malignancy; otherwise, surveillance seems a good option.

Malignant degeneration of presumed pancreatic mucinous cystic neoplasms takes several years, if it occurs at all. Mural nodules, enhancing walls or cysts of 50 mm or larger call for surgical resection owing to an increased risk of malignancy; otherwise, surveillance seems a good option.

Genetic profile of primary mucinous cystadenocarcinoma of the breast-A case report.

Primary mucinous cystadenocarcinoma of the breast is a rare neoplasm with few reports in the literature. Here, we report for the first time a comprehensive genetic profile of a primary mucinous cystadenocarcinoma of the breast, using next-generation sequencing 580 cancer-associated gene panel. Mutations in TP53, RB1, and BAP1 were identified. The findings suggest that this tumor is driven mostly by abnormalities in tumor suppressor genes, primarily involved in cell cycle control and chromatin remodeling. Molecular characterization of additional primary mucinous cystadenocarcinomas of the breast is warranted and might provide information related to its biology and behavior.

[Mucinous Cystadenocarcinoma with a Sarcomatous Component Arising from the Sigmoid Mesocolon-A Case Report].

A 53‒year‒old female was referred to our hospital for abdominal pain. A cystic tumor evolving since 12 years, which was suspected of being a lymphocyst, was detected in her left lower abdomen. Computed tomography(CT)revealed the cystic tumor with enhanced 80 mm enlarged regions. Regarding the laboratory data, inflammatory parameters and tumor markers such as CA19‒9, CEA, and CA125 were elevated. Mucinous cystadenocarcinoma was highly suspected and a surgery was performed. Laparotomy showed that the tumor was located in the sigmoid mesocolon and there were multiple peritoneal disseminations. The tumor could not be separated from the sigmoid colon; therefore, tumor resection with partial sigmoidectomy was performed. The resected specimens showed mucus and solid lesions in the cystic tumor. The pathological findings revealed that the cystic tumor from the sigmoid mesocolon was a mucinous cystadenocarcinoma with large spindle‒ shaped atypical cells, which were considered to have undergone sarcomatous changes. No cases of mucinous cystadenocarcinoma with sarcoma arising from the sigmoid mesocolon have been previously reported. The prognosis of mucinous cystic neoplasm with sarcoma is suspected to be very poor, and the accumulation of such cases could help in improving their treatment.

Primary retroperitoneal mucinous cystadenocarcinoma in pregnancy - case report.

INTRODUCTION: Primary retroperitoneal mucinous cystadenoma (PRMC) and its malignant variant - cystadenocarcinoma are extremely rare tumors known only from case studies and reviews. PRMC is a cystic tumor of the retroperitoneum, which remains asymptomatic for a long time and can reach significant proportions. It occurs mainly in women. CASE REPORT: We present the case of a 38-year-old healthy woman with diagnosed resistance in the right mesogastrium during a c-section. The delivery was terminated without a surgical intervention. The above mentioned resistance was examined further by ultrasound, computed tomography and magnetic resonance imaging. All imaging examinations showed a solid - cystic bilocular expansion, which looked like a mesenteric cyst in the right paracolic area. The patient was asymptomatic at all times, with only a palpable resistance of the abdominal wall. In November 2020, the patient underwent an elective surgery - extirpation of the cystic tumor and prophylactic appendectomy. The operation was performed classically, via midline laparotomy without perioperative perforation of the cystic tumor and without complications in the postoperative period. The histopathological examination showed a malignant variant of PRMC. So far, the patient remains free of any problems and is followed at the department of oncology. CONCLUSION: The goal of treatment is to achieve complete surgical removal of the tumor without its perioperative perforation. Due to the rare occurrence of the disease, there are no guidelines for the diagnosis and treatment of PRMC. Precisely because PRMC is a rare tumor, it should be part of the differential diagnosis of cystic tumors of the retroperitoneum, especially when young women are concerned.

Validation of European evidence-based guidelines and American College of Gastroenterology guidelines as predictors of advanced neoplasia in patients with suspected mucinous pancreatic cystic neoplasms.

BACKGROUND AND AIM: The European evidence-based guidelines (EEG) and American College of Gastroenterology Guidelines (ACGG) have been published to guide the management of pancreatic cystic lesions. We aim to evaluate the value of both guidelines in predicting advanced pancreatic cystic lesions (A-PCLs) with preoperatively imaging-suspected cystic mucinous pancreatic neoplasms (cMNs). METHODS: One hundred ninety-eight patients who underwent resections from 2013 to 2019 for suspected cMNs were retrospectively reviewed. Receiver operating characteristic curves were calculated and compared with measure diagnostic value. RESULTS: Sixty-two patients were diagnosed with A-PCLs pathologically. Cross-imaging modalities had comparable diagnostic accuracy to endoscopic ultrasound in type classification and A-PCLs prediction. Receiver operating characteristic curve comparison analyses showed that EEG absolute + MCN (EEGAM ) and EEG relative + MCN (EEGRM ) having at least one indications criteria were comparable to the ACGG (P = 0.21 and P = 0.45). For the criteria having at least two indications, ACGG was superior to EEGAM (P = 0.001) but comparable to EEGRM (P = 0.12). EEGAM ≥ 1 indication criteria was superior to ≥ 2 indications criteria (P = 0.02). EEGRM ≥ 1 indication criteria had comparable diagnostic performance with ≥ 2 indications criteria (P = 0.86). ACGG ≥ 2 indications criteria was superior to ≥ 1 indication criteria (P = 0.02). CONCLUSION: On the basis of cross-imaging evaluations, both sets of guidelines were found to be helpful in identifying A-PCLs in suspected cMNs with comparable performance. EEGAM  ≥ 1 indication criteria was superior to ≥ 2 indications criteria. ACGG ≥ 2 indications criteria was superior to ≥ 1 indication criteria.

Excellent Accuracy of Glucose Level in Cystic Fluid for Diagnosis of Pancreatic Mucinous Cysts.

BACKGROUND: CEA in pancreatic cystic fluid (PCF) is standard for mucinous cysts diagnosis. Glucose is an alternative, but its accuracy remains poorly described. AIMS: To evaluate PCF glucose using a glucometer and compare its accuracy with CEA for mucinous cysts diagnosis. MATERIALS AND METHODS: In frozen PCF obtained by EUS-FNA, glucose was evaluated using a glucometer. CEA and cytology were available as standard of care. The accuracy of glucose and CEA was calculated using receiver operator (ROC) curves. Definitive diagnoses were surgical or clinicopathological. RESULTS: We evaluated 82 patients with a mean age of 61.3 ± 14.8 years (25-91), predominantly (59%) females. Diagnoses included 17 serous cystadenomas, five pseudocysts, 20 intraductal papillary mucinous neoplasms, three mucinous cystic neoplasms, five adenocarcinomas, four neuroendocrine tumors, two other types, 26 non-defined. The median glucose levels (interquartile range) were 19 mg/dL (19-19) in mucinous and 105 mg/dL (96-127) in non-mucinous cysts (p < 0.0001). The median CEA level was 741 ng/mL (165-28,567) in mucinous and 9 ng/mL (5-19) in non-mucinous cysts (p < 0.0001). For mucinous cyst diagnosis, a CEA > 192 ng/mL had a sensitivity of 72% (95% CI 51-88) and a specificity of 96% (95% CI 82-100), and ROC analysis showed an area under the curve (AUC) of 0.842 (95% CI 0.726-0.959), while glucose < 50 mg/dL had a sensitivity of 89% (95% CI 72-98), a specificity of 86% (95% CI 67-96), and an AUC of 0.86 (95% CI 0.748-0.973). Pseudocysts presented low glucose, identically to mucinous cysts, with CEA allowing differential diagnosis. CONCLUSION: Glucose measured by a glucometer is accurate for mucinous cyst diagnosis, with significantly higher levels in non-mucinous cysts, except pseudocysts.

Mucinous cystadenocarcinoma in the renal pelvis: primary or secondary? Case report and literature review.

INTRODUCTION: Cystic lesions in the renal pelvis may cause a diagnostic dilemma. These lesions may be benign or (pre)malignant and primary of secondary. CASE REPORT: A 65-year-old woman presents with a complex cystic mass in the lower pole of the left kidney measuring approximately 16 cm in size and classified as Bosniak type 2F with minimally thickened septa and thick calcifications on non-contrast-enhanced computed tomography. The histopathological findings are consistent with a mucinous cystadenocarcinoma in the renal pelvis. Given the absence of a primary focus and based on clinical and radiological examination, the diagnosis of a primary renal neoplasm is preferred. DISCUSSION: A review of the literature is performed to evaluate the histological differential diagnosis and confirm the diagnosis. Epidemiology with an overview of available similar cases since 2009, as well as etiological factors, treatment and prognosis was reviewed. CONCLUSION: Primary renal mucinous cystadenocarcinoma is an exceedingly rare tumor. Histopathology still remains the gold standard for the diagnosis of this tumor. Because of the rarity, secondary involvement from more common sites, such as ovary and gastrointestinal tract, should be thoroughly excluded.

Multiple KRAS mutations in the non-mucinous epithelial lining in the majority of mucinous cystic neoplasms of the pancreas.

AIMS: Mucinous cystic neoplasms (MCNs) of the pancreas are cystic neoplasms lined by mucinous lining epithelium (MLE) with associated ovarian-type stroma. Although a non-MLE (NMLE) can be observed in some MCNs, whether cystic neoplasms with ovarian-type stroma and NMLE should be classified as MCNs or separately designated is debated. METHODS AND RESULTS: To test this, NMLEs were defined as flat or cuboidal epithelial cells without intracytoplasmic mucin. A total of 112 MCNs were reviewed, and the epithelium was classified as NMLE or MLE. A total of 110 females and two males with a mean age of 46.5 ± 12.3 years were included in this study. At least focal NMLE was noted in 76.8% (86/112) of MCNs. The mean percentage of the neoplastic epithelium that was NMLE in these 86 cases was 46%. NMLE was predominant (>50%) in 38.4% (43/112) of cases. MCNs with NMLE were smaller (42 ± 21 mm) than those with MLE (60 ± 36 mm, P < 0.001), and all NMLEs had low-grade dysplasia. Twelve MCNs with NMLE or MLE were selected for KRAS mutation analysis with droplet digital polymerase chain reaction after laser capture microdissection. All 12 MCNs showed multiple types of KRAS mutation, which were detected in 92% (11/12) of NMLE foci and 89% (8/9) of MLE foci. Predominant NMLE was common in small MCNs with low-grade dysplasia. CONCLUSIONS: Clonal KRAS mutations were observed in both NMLE and MLE, supporting the hypothesis that MCNs with NMLE should be classified as MCNs.

Cyst location and presence of high grade dysplasia or invasive cancer in intraductal papillary mucinous neoplasms of the pancreas: a seven institution study from the central pancreas consortium.

BACKGROUND: Traditionally, intraductal papillary mucinous neoplasms (IPMNs) of the pancreas with "high risk stigmata" (HRS) or "worrisome features" (WF) are referred for resection. We aim to assess if IPMN location is predictive of harboring either high grade dysplasia (HGD) or invasive cancer (IC). METHODS: Patients undergoing resection for IPMN from seven institutions between 2000 and 2015 (n = 275) were analyzed. HRS and WF were defined by the 2012 Fukuoka international consensus guidelines. RESULTS: 168 (61%) patients had head/uncinate cysts, while 107 (39%) had neck/body/tail cysts. No differences were noted between groups with regard to age, duct type, cyst size, or presence of at least one WF. Patients with cysts in the head/uncinate were more often male (55% vs. 40%), had at least one HRS (24% vs. 11%), and more often harbored HGD or IC(49% vs. 27%)[all p < 0.05]. On multivariate analysis, only cyst location in the head/uncinate remained associated with presence of HGD or IC(odds ratio 4.76, p = 0.02). DISCUSSION: Cyst location is predictive of HGD or IC in patients with IPMNs. Head/uncinated cysts are more likely to harbor malignancy compared to those of the neck/body/tail. Additional studies are needed to confirm these findings, however, cyst location should be considered part of the decision making process for surveillance vs. resection for IPMNs.

[Appendix Cancer with Long-Term Survival after Multimodality Therapy-A Case Report].

We report a case of long-term survival in a 65-year-old woman with recurrent appendix cancer. In March 2002, she was diagnosed with appendix cancer and underwent ileocecal resection. The pathological diagnosis was mucinous cystadenocarcinoma, pT2N0M0, Stage Ⅰ. In April 2006, ovariohysterectomy was performed for right ovarian metastases. In February 2011, tumor resection was performed for disseminated recurrence after 4 courses of systemic chemotherapy(bevacizumab plus mFOLFOX6). Although no recurrent lesions had been detected on imaging, stepwise elevation of serum CEA level was observed from June 2016. In November 2017, computed tomography scan revealed a slow-growing tumor on the liver. We performed partial resection of the right hemidiaphragm for the disseminated tumor, and the pathological diagnosis was mucinous adenocarcinoma. The patient has been on continuous postoperative follow-up without recurrence until June 2019. Appendix cancer is relatively rare and has a worse prognosis compared to colorectal cancer because of higher frequency of disseminated metastases. With the multimodality therapy, our patient showed long-term survival over 17 years despite a disseminated recurrence. In cases of mucinous cystadenocarcinoma of the appendix, persistent follow-up and aggressive treatment are recommended.

[A Case of Mucinous Cystoadenocarcinoma with Metastatic Liver Tumor in a Young Woman Lacking Specific Findings].

The patient was a 17-year-old woman. An abnormal urinalysis was observed, and abdominal echography showed a pancreatic cystic mass. At the first examination, computed tomography(CT)and endoscopic ultrasound(EUS)showed a unilocular cystic mass of 60mm in size in the pancreatic body and tail, and no malignant findings were observed. After 14 months, CT and positron emission tomography-computed tomography(PET-CT)showed that the cystic mass had a mural nodule with FDG accumulation, and presence of a tumor in hepatic S8 with FDG accumulation. Laparoscopic distal pancreatectomy and hepatic subsegmentectomy of S8 were performed for diagnostic and therapeutic purposes. The pathological diagnosis was mucinous cystadenocarcinoma(MCC)and metastatic liver cancer in the form of MCC. S-1 was administered after surgery. Nine months after resection, multiple metastatic liver tumors were found, and GEM plus nab-PTX was administered. After 2 courses of treatment, the patient is still alive without new lesions.

Risk of malignancy in resected pancreatic mucinous cystic neoplasms.

BACKGROUND: Pancreatic mucinous cystic neoplasms (MCNs) are rare mucin-producing cystic tumours defined by the presence of ovarian-type stroma. MCNs have a malignant potential and thus surgery is frequently performed. The aim of this cohort study was to define better the criteria for surgical resection in patients with MCN. METHODS: This multicentre retrospective study included all resected MCNs between 2003 and 2015 in participating centres. Lesions without ovarian-type stroma were excluded. Patient characteristics, preoperative findings, histopathology findings and follow-up data were recorded. RESULTS: The study included 211 patients; their median age was 53 (range 18-82) years, and 202 (95·7 per cent) were women. Median preoperative tumour size was 55 (range 12-230) mm. Thirty-four of the 211 (16·1 per cent) were malignant, and high-grade dysplasia (HGD) was found in a further 13 (6·2 per cent). One-third of MCNs in men were associated with invasive cancer, compared with 15·3 per cent in women. Five cases of malignant transformation occurred in MCNs smaller than 4 cm. All cases of malignancy or HGD were associated with symptoms or features of concern on preoperative cross-sectional imaging. In multivariable analysis, raised carbohydrate antigen 19-9 (odds ratio (OR) 10·54, 95 per cent c.i. 2·85 to 218·23; P < 0·001), tumour size (OR 4·23, 3·02 to 11·03; P = 0·001), mural nodules (OR 3·55, 1·31 to 20·55; P = 0·002) and weight loss (OR 3·40, 2·34 to 12·34; P = 0·034) were independent factors predictive of malignant transformation. CONCLUSIONS: Small indeterminate MCNs with no symptoms or features of concern may safely be observed as they have a low risk of malignant transformation.

Resection of biliary mucinous cystic neoplasms of the liver: a prospective cohort series of 13 consecutive patients.

BACKGROUND: Biliary mucinous cystic neoplasms (BMCNs) are uncommon neoplastic septated intrahepatic cysts which are often incorrectly diagnosed and have the potential for malignant transformation. OBJECTIVE: To assess the outcome of surgical resection of BMCNs. METHOD: A prospective liver surgery database was used to identify patients who underwent surgery at Groote Schuur Hospital Complex for BMCN from 1999 to 2015. Demographic variables including age and gender were documented as well as detailed preoperative imaging, location and size, operative treatment, extent of resection, histology, postoperative complications and outcome. RESULTS: Thirteen female patients (median age 45 years) had surgery. Eleven were diagnosed by imaging for symptoms. Two were jaundiced. One cyst was found during an elective cholecystectomy. Five cysts were located centrally in the liver. Before referral three cysts were treated with percutaneous drainage and two were treated with operative deroofing. Six patients had anatomical liver resections and seven patients had non anatomical liver resections of which two needed ablation of residual cyst wall. One patient needed a biliary-enteric reconstruction to treat a fistula. Median operative time was 183 minutes (range: 130-375). No invasive carcinoma was found. There was no operative mortality. One surgical site infection and one intra-abdominal collection were treated. Two patients developed recurrent BMCN after 24 months. CONCLUSION: BMCNs should be considered in middle aged women who have well encapsulated multilocular liver cysts. Treatment of large central BMCNs adjacent to vascular and biliary structures may require technically complex liver resections and are best managed in a specialised hepato-pancreatico-biliary unit.