Appendiceal mucinous neoplasm mimics ovarian tumors: Challenges for preoperative and intraoperative diagnosis and clinical implication

A Unique Case of Intra-Abdominal Diffuse Lymphangiomatosis Mimicking a Pseudomyxoma Peritonei

INTRODUCTION

Localized cystic lymphangiomas (CL) are rare benign tumors deriving from the lymphatic system. CL is diagnosed more frequently in children than in the adult population and, although commonly affecting the cervical and axillary regions, can develop in various parts of the body. Abdominal cystic lymphangioma (ACL) comprises less than 5% of all CL cases.

CASE PRESENTATION

A 35-year-old female patient with a history of benign appendectomy in childhood was transferred to our tertiary center for the operative management of a suspected extensive pseudomyxoma peritonei (PMP). In accordance with the multidisciplinary team discussion, cytoreductive surgery with hyperthermic intraperitoneal chemotherapy was planned. Intraoperatively, a typical "jelly belly" with high disease burden throughout the abdominal cavity and the small pelvis was found. A multi-visceral resection with complete cytoreduction (CCR 0) was performed. The postoperative histopathological findings revealed a diffuse, partially cystic lymphangiomatosis involving the peritoneum extensively without evidence of PMP or malignancy.

CONCLUSIONS

ACLs are uncommon in the adult population, and diffuse peritoneal involvement is even rarer. Surgical management with complete resection is the preferred treatment option. Other benign cysts, as well as infectious diseases and malignancy, should be considered during the preoperative workup.

LAMN port-site metastasis after laparoscopic oophorectomy for a presumed ovarian tumour treated with CRS and HIPEC

Low-grade appendiceal mucinous neoplasm (LAMN) may culminate as a mucin-secreting disease known as pseudomyxoma peritonei (PMP). Once the diagnosis of LAMN and PMP is made, cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS and HIPEC) are indicated.Herein, we present a female patient in her 50s who was diagnosed with an ovarian mass for which she underwent laparoscopic oophorectomy. As the pathology of the ovary showed a tumour of gastrointestinal origin, she then underwent CRS and HIPEC with a final pathology of LAMN. Six weeks later, a mucinous lesion confined to the abdominal wall was detected on a postoperative CT. Suspected for port-site metastasis at the laparoscopic trocar site, we treated this lesion using the same principles of treatment as the intra-abdominal disease. The abdominal wall mass was surgically resected, and the cavity created was irrigated with mitomycin C. On 30 months of follow-up, the patient had no evidence of disease.

Ovarian Causes of Pseudomyxoma Peritonei (PMP)-A Literature Review

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare, progressive, slowly growing, inadequately understood neoplasm with a 5-year progression-free survival rate of as low as 48%. It is characterized by varying degrees of malignancy and the production of mucinous and gelatinous structures. Typically, the development of pseudomyxoma peritonei is associated with the rupture of appendiceal mucinous tumors and other gastrointestinal or ovarian mucinous tumors. The goal of our literature review was to identify various aspects that characterize the ovarian causes of pseudomyxoma peritonei.

MATERIALS AND METHODS

The authors performed an extensive literature search between 1 February 2024 and 2 March 2024 on the following databases: Pubmed, Scopus, Oxford Journals, and Reaxys, and the findings were summarized into seven main clinical and paraclinical situations.

RESULTS

According to our research, the main instances in which pseudomyxoma peritonei can be triggered by an ovarian cause are the following: (1) mucinous cystadenoma; (2) mucinous ovarian cancer; (3) colon cancer with ovarian metastasis; (4) malignant transformation of an ovarian primary mature cystic teratoma; (5) appendiceal mucocele with peritoneal dissemination mimicking an ovarian tumor with peritoneal carcinomatosis; (6) mucinous borderline tumor developing inside an ovarian teratoma; and (7) the association between a mucinous bilateral ovarian cancer and a colonic tumor.

CONCLUSIONS

In our study, we aimed to provide a comprehensive overview of the ovarian causes of pseudomyxoma peritonei, including its epidemiology, imagery characteristics, symptoms, current treatment, and promising future therapies, in the hopes of finding feasible solutions, as a lack of understanding of this mucus-secreting malignant disease increases the risk of delayed diagnosis or uncontrolled deterioration.

Low grade appendiceal mucinous neoplasm metastatic to the ovary: A case report and intraoperative assessment guide

INTRODUCTION

Incidence of low grade appendiceal mucinous neoplasm is increasing. Preoperatively, it may present similarly to primary ovarian malignancy. This case report describes a case of presumed ovarian malignancy with final pathologic diagnosis of low grade appendiceal mucinous neoplasm. We also propose several surgical strategies to approach this conundrum.

PRESENTATION OF CASE

A postmenopausal woman with abdominal pain was found to have a 30 cm abdominopelvic mass with elevated CA-125 and CEA presumably a primary ovarian malignancy. During surgical staging, intraoperative findings were notable for an appendiceal mass. Intraoperative surgical oncology consultation recommended appendectomy for diagnostic purposes. Following primary surgery and final pathologic diagnosis, she underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

DISCUSSION

Low grade appendiceal mucinous neoplasm should be within the differential diagnosis of gynecologic surgeons when presented with a patient with large volume ascites and biopsy of acellular mucin. Intraoperatively, an abnormal appearing appendix with normal appearing gynecologic structures should trigger suspicion for appendiceal rather than ovarian origin. Preoperative symptoms, imaging studies, tumor markers, and frozen section pathology may not be able to differentiate between appendiceal and epithelial ovarian malignancies.

CONCLUSION

A recognition of mucinous material and abnormal appearing appendix should prompt the surgeon to consider performing an appendectomy to obtain primary pathologic diagnosis. A high level of suspicion could better optimize the patient for a joint case with the appropriate surgeons. Given the documented disguise of low grade appendiceal mucinous neoplasm as primary ovarian cancer and its increasing incidence, diagnosis and general understanding of treatment should be understood.

Incidence and outcomes of delayed presentation and surgery in peritoneal surface malignancies

Background

Peritoneal surface malignancies (PSM) present insidiously and often pose diagnostic challenges. There is a paucity of literature quantifying the frequency and extent of therapeutic delays in PSM and its impact on oncological outcomes.

Methods

A review of a prospectively maintained registry of PSM patients undergoing Cytoreductive Surgery and Hyperthermic Intra-peritoneal Chemotherapy (CRS-HIPEC) was conducted. Causes for treatment delays were identified. We evaluate the impact of delayed presentation and treatment delays on oncological outcomes using Cox proportional hazards models.

Results

319 patients underwent CRS-HIPEC over a 6-years duration. 58 patients were eventually included in this study. Mean duration between symptom onset and CRS-HIPEC was 186.0 ± 37.1 days (range 18-1494 days) and mean duration of between patient-reported symptom onset and initial presentation was 56.7 ± 16.8 days. Delayed presentation (> 60 days between symptom onset and presentation) was seen in 20.7% (n=12) of patients and 50.0% (n=29) experienced a significant treatment delay of > 90 days between 1^st presentation and CRS-HIPEC. Common causes for treatment delays were healthcare provider-related i.e. delayed or inappropriate referrals (43.1%) and delayed presentation to care (31.0%). Delayed presentation was a significantly associated with poorer disease free survival (DFS) (HR 4.67, 95% CI 1.11-19.69, p=0.036).

Conclusion

Delayed presentation and treatment delays are common and may have an impact on oncological outcomes. There is an urgent need to improve patient education and streamline healthcare delivery processes in the management of PSM.

Misdiagnosed appendiceal mucinous neoplasms and primary ovarian mucinous tumors present with different pre- and intraoperative characteristics

Objective

To identify the differences between the pre- and intraoperative characteristics in misdiagnosed appendiceal mucinous neoplasms (AMNs) and those in primary ovarian mucinous tumors (POMTs) and to establish an effective model for differentiating AMNs from pelvic mucinous tumors.

Methods

This study enrolled 70 AMN patients who were misdiagnosed with ovarian tumors and 140 POMT patients who were treated from November 1998 to April 2021 at Peking Union Medical College Hospital. The clinical features and operative findings of the two groups of patients were collected and compared.

Results

There were significant differences in age and menopausal status, but no difference in the patients’ clinical manifestations between the two groups. The preoperative serum CA125 and CA199 levels were not different between the two groups. The CEA level (31.04 ± 42.7 vs. 7.11 ± 24.2 ng/ml) was higher in the misdiagnosed AMN group (P < 0.001). The AMNs were smaller than the POMTs that were measured preoperatively by ultrasonography (US) (P<0.05) and measured at surgery (P<0.05). Furthermore, the patients with AMNs more commonly had multinodularity and ascites noted on the preoperative US (P<0.001), on CT (P<0.001), and at surgery (P< 0.001). The two groups also differed in the presence of bilateral disease, in the appendiceal appearance and peritoneal dissemination. Subsequently, a prediction model was developed using multivariable logistic regression, which was evaluated through internal validation.

Conclusions

The suspicion of a nongenital organs originated tumor especially origing from appendiceal should be considered in a patient who is older, tumor size less than 12cm, multinodular, presence of mucinous ascites, and elevated serum CEA levels. Bilateral ovarian involvement, peritoneal dissemination, and an abnormal appendiceal appearance found during surgery were the typical features associated with AMNs.

Appendiceal tumors in patients undergoing primary surgery for mucinous ovarian tumors in a tertiary hospital, in Southern Thailand

OBJECTIVE

To evaluate the prevalence of appendiceal tumors in patients diagnosed with mucinous ovarian tumors and to determine factors associated with coexisting appendiceal tumors.

MATERIALS AND METHODS

Retrospective review of all patients who were diagnosed with mucinous ovarian tumors and underwent an appendectomy during surgery between January 2002 and June 2017 was performed. Univariate and multivariate logistic regression analyses were used to identify risk factors for coexisting appendiceal tumors.

RESULTS

A total of 303 patients with mucinous ovarian tumors who underwent appendectomy were identified, including 77 (25.4%) mucinous cystadenoma and 226 (74.6%) mucinous borderline tumor or carcinoma. Twenty-one (6.9%) had coexisting appendiceal tumors including 8 that were primary appendiceal mucinous adenocarcinomas, 6 low-grade appendiceal mucinous neoplasms, 6 secondary appendiceal metastasis from the ovary, and one hyperplastic polyp. None of mucinous cystadenoma had coexisting appendiceal tumors. Multivariate analysis revealed advanced age ≥50 years, previous rupture of ovarian tumors, abdominal extension of tumors, and grossly abnormal appendix were independent factors for coexisting appendiceal tumors.

CONCLUSION

Prevalence of coexisting appendiceal tumors in mucinous ovarian tumors was not uncommon. The risk factors were grossly abnormal appendix, abdominal extension of tumor, previous rupture of ovarian tumors, and advanced age.

Neoplasias apendiculares incidentales

Las neoplasias apendiculares se presentan hasta en el 50 % de los casos como un episodio de apendicitis aguda. Existen características demográficas, clínicas y radiológicas que aumentan las posibilidades de un tumor apendicular subyacente, sin embargo, en la mayoría de los casos, son los hallazgos intraoperatorios los que alertan al cirujano. A pesar de que el tipo histológico determina la radicalidad del manejo quirúrgico de estos pacientes, algunas características macroscópicas pueden orientar a las patologías específicas y a una conducta adecuada. En general, los objetivos del manejo quirúrgico inicial se cumplen con una resección limitada al apéndice cecal, asociada a la citología de mucina y biopsia de los implantes peritoneales si están presentes, reservando las resecciones extendidas, como hemicolectomía derecha oncológica, para los pacientes con compromiso extenso de la base o del mesenterio apendicular ante la sospecha de neoplasias neuroendocrinas o adenocarcinoma del apéndice cecal.

Incidentally found mucinous epithelial tumors of the appendix with or without pseudomyxoma peritonei: diagnostic and therapeutic algorithms based on current evidence

Mucinous appendiceal tumors with or without the pseudomyxoma peritonei (PMP) syndrome are rare, but often present as an incidental finding. The confusing histology and lack of large prospective trials result in a considerable diagnostic and therapeutic challenge in these patients. We propose treatment algorithms in patients with incidentally found mucinous epithelial appendiceal tumors, with or without PMP, based on the currently available evidence. The therapeutic approach should take into account the histology and grade of the primary appendix tumor, as well as those of the associated peritoneal disease.

Ovarian mucinous and seromucinous neoplasms: problematic aspects and modern diagnostic approach

The morphological spectrum of primary ovarian mucinous and seromucinous tumours is broad and presents an array of diagnostic challenges, many unique to these tumour types. This reflects the heterogeneous nature of these lesions, their varied histogenesis and evolving classification systems over recent decades, with further modification to the seromucinous category incorporated in the recently published 5^th edition of the WHO Classification of Female Genital Tumours. In this review we provide an update on the classification of these neoplasms and discuss their histogenesis and diverse morphology, focusing on areas which are diagnostically problematic. We also cover tumour grading, differential diagnosis, immunohistochemistry, the recent elucidation of the molecular underpinnings of ovarian mucinous neoplasia and discuss the gross and intraoperative handling of these tumours. A number of diagnostic issues remain unresolved highlighting the importance of further research on this front, as well as a multidisciplinary approach in the care of patients with ovarian mucinous and seromucinous neoplasia.

Low-Grade Appendiceal Mucinous Neoplasm (LAMN) Primarily Diagnosed as an Ovarian Mucinous Tumor

BACKGROUND

Low-grade appendiceal mucinous neoplasms (LAMN) are detected in 0.7 to 1.7% of all appendicectomies. The diagnosis can be challenging, particularly in female patients where the differential diagnosis of primary appendiceal and ovarian mucinous neoplasms is unclear. Case Presentation. A 71-year-old female was referred to our tertiary hospital with the working diagnosis of a right ovarian cystic tumor. The lesion was identified through a transvaginal ultrasound performed for vague lower abdominal pain symptoms. CT scan confirmed these findings. Intraoperatively, an appendiceal mucocele was identified and a right hemicolectomy was performed. The histopathology examination revealed a LAMN. Six months later, the patient remains disease-free. A close biannual oncological follow-up has been suggested.

CONCLUSION

This case underlines the difficulty in determining the origin of mucinous neoplasms of the right pelvic area. Mucocele of the appendix should be considered in the differential diagnosis of a mass in the right iliac fossa.

Low-grade mucinous appendiceal neoplasm mimicking an ovarian lesion: A case report and review of literature

BACKGROUND

Appendiceal tumors are rare lesions that may not be easily differentiated from primary ovarian lesions preoperatively, despite the use of advanced diagnostic methods by experienced clinicians.

CASE SUMMARY

A 59-year-old G2P2 woman, with chronic pelvic pain, underwent a pelvic ultrasound that revealed an adnexal mass measuring 58 mm × 34 mm × 36 mm, with irregular borders, heterogeneous echogenicity, no color Doppler vascularization and without acoustic shadowing. Normal ovarian tissue was visualized in contact with the lesion, and it was impossible to separate the lesion from the ovary by applying pressure with the ultrasound probe. Ascites, peritoneal metastases or other alterations were not observed. With the international ovarian tumor analysis ADNEX model, the lesion was classified as a malignant tumor (the risk of malignancy was 27.1%, corresponding to Ovarian-Adnexal Reporting Data System category 4). Magnetic resonance imaging confirmed the presence of a right adnexal mass, apparently an ovarian tumor measuring 65 mm × 35 mm, without signs of invasive or metastatic disease. During explorative laparotomy, normal morphology of the internal reproductive organs was noted. A solid mobile lesion involved the entire appendix. Appendectomy was performed. Inspection of the abdominal cavity revealed no signs of malignant dissemination. Histopathologically, the appendiceal lesion corresponded to a completely resected low-grade mucinous appendiceal neoplasm (LAMN).

CONCLUSION

The appropriate treatment and team of specialists who should provide health care to patients with seemingly adnexal lesions depend on the nature (benign vs malignant) and origin (gynecological vs nongynecological) of the lesion. Radiologists, gynecologists and other pelvic surgeons should be familiar with the imaging signs of LAMN whose clinical presentation is silent or nonspecific. The assistance of a consultant specializing in intestinal tumors is important support that gynecological surgeons can receive during the operation to offer the patient with intestinal pathology an optimal intervention.

Impact of Previous Gynecologic Surgical Procedures on Outcomes of Non-Gynecologic Peritoneal Malignancies Mimicking Ovarian Cancer: Less Is More?

BACKGROUND

Non-gynecologic rare peritoneal surface malignancies (PSMs) often are misdiagnosed as disseminated ovarian cancer and initially treated by gynecologic surgeons. This study aimed to assess whether these previous maneuvers (i.e., full surgical staging and/or cytoreductive attempts) affect outcomes after the definitive surgery performed in a tertiary center.

METHODS

The study reviewed 298 women affected by non-gynecologic PSM who underwent cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) after previous gynecologic surgery. Prior surgery was categorized as limited surgery (pLS: abdominal exploration with biopsy plus adnexectomy and/or appendectomy) or extended surgery (pES: full surgical staging or cytoreductive attempts including hysterectomy with bilateral salpingo-oophorectomy).

RESULTS

Of the 298 patients, 143 had pLS and 153 had pES. Morbidity was similar between the groups (P = 0.143), but the pES group had more severe urinary tract injuries (19 vs. 3; P < 0.001), longer operating time (585.9 vs. 506.7; P = 0.027), and more patients needing more than two anastomoses (41 vs. 26; P = 0.033). Age older than 55 years (odds ratio [OR] 2.42; P = 0.009) and number of anastomoses (OR 3.17; P = 0.002) correlated with severe morbidity; pES correlated with urinary tract grades 3 and 4 injuries (OR 7.9; P = 0.001). The 5-year cumulative incidence of locoregional relapse was significantly higher in the pES group (0.41 vs. 0.27; P = 0.012; median follow-up period, 69 months). The multivariate analysis identified a Peritoneal Carcinomatosis Index (PCI) higher than 20 and pES as independent risk factors.

CONCLUSION

For women undergoing CRS±HIPEC for non-gynecologic PSM, the risk for locoregional relapse and severe postsurgical urinary tract complications is increased by pES. Therefore, prior full surgical staging or cytoreductive attempts without definitive gynecologic histology should be avoided. Prophylactic ureteral stenting and stricter oncologic follow-up assessment must be considered in this scenario.

Gross mucinous multinodular appearance aids in the identification of ovarian metastases in low-grade appendiceal mucinous neoplasms during intraoperative consultation

Ovarian metastases of low-grade appendiceal mucinous neoplasms (LAMNs) show grossly abundant nodular mucous cells, with a gross mucinous multinodular appearance and a histological resemblance to primary ovarian mucinous tumors (POMTs). This study aimed to elucidate the utility of gross features including the gross mucinous multinodular appearance and available clinical information at the time of intraoperative consultation, in distinguishing the ovarian metastases of LAMNs from POMTs or the ovarian metastases of colorectal cancer (CRC). In total, 776 patients with primary ovarian tumor and 68 patients with ovarian metastases underwent intraoperative consultation during 1998-2018. Of the total cases, 4 ovarian metastases of LAMNs, 19 ovarian metastases of CRC, and 50 POMTs (36 borderline tumors and 14 carcinomas) were identified. The gross features including the gross mucinous multinodular appearance were analyzed based on the gross photographs obtained before formalin fixation and the available clinical information collected during intraoperative consultation. The analysis indicated that the ovarian metastases of LAMNs significantly presented with gross mucinous multinodular appearance (4/4 vs. 0/50, P < 0.0001), extraovarian disease (4/4 vs. 2/50, P < 0.0001), ovarian surface involvement (3/4 vs. 2/50, P = 0.0016), and abnormal appendix (4/4 vs. 0/50, P < 0.0001) as compared to POMT. Moreover, the gross mucinous multinodular appearance was a distinguishable feature between the ovarian metastases of LAMNs and ovarian metastases of CRC (4/4 vs. 0/19, P = 0.0001). Based on these results, we proposed an algorithm to diagnose ovarian tumors using the gross mucinous multinodular appearance. Thus, recognizing unique gross features including the gross mucinous multinodular appearance would be useful for both pathologists and surgeons to accurately diagnose ovarian metastases of LAMNs during intraoperative consultation.

Management of Low-Grade Appendiceal Mucinous Neoplasm with Extensive Peritoneal Spread Diagnosed during Pregnancy: Two Case Reports and Literature Review

BACKGROUND

Clinical decisions in patients with peritoneal dissemination of low-grade appendiceal mucinous neoplasms (LAMN) diagnosed during pregnancy are challenging. However, their slow progression and favorable prognosis allow deferring definitive treatment until after spontaneous delivery, a reasonable period of breastfeeding, and fertility preservation. Case Presentation. Two pregnant patients were incidentally diagnosed with LAMN and extensive peritoneal spread at 20 weeks gestation and at cesarean section. Treatment with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in both cases was delayed until spontaneous delivery at term and breastfeeding in the first patient and breastfeeding and fertility preservation in the second patient. Both patients remain disease-free for over 5 years, and their children are healthy. The literature review highlights the challenges that physicians face in treating pregnant patients with stage IV appendiceal tumors.

CONCLUSION

Pregnancy management decisions in patients with peritoneal spread from mucinous appendiceal tumor should be based on understanding the tumor biology and prognosis. Definitive treatment in pregnant patients with favorable tumors, such as LAMN, may be delayed until spontaneous delivery without compromising maternal survival.

Diagnostic Discordance in Intraoperative Frozen Section Diagnosis of Ovarian Tumors: A Literature Review and Analysis of 871 Cases Treated at a Japanese Cancer Center

BACKGROUND

This study examined the accuracy and pitfalls associated with frozen section diagnosis of primary ovarian tumors and ovarian metastases based on the 2014 World Health Organization classification (WHO) criteria and proposed improvements from a pathologist's perspective.

METHODS

We microscopically reviewed 871 cases of primary ovarian tumor (N = 802) and ovarian metastasis (N = 69) and compared the results of frozen sections with the final diagnosis. Malignant potential concordance (benign, borderline, or malignant) and specific discordant diagnosis rates were analyzed. Finally, we conducted a unique literature review of specific diagnostic errors in the frozen section diagnosis of primary ovarian tumors.

RESULTS

Of 802 primary ovarian tumors, 50 (6.2%) cases showed discordant diagnoses in which mucinous carcinoma (40.5%), low-grade serous carcinoma (LGSC; 31.3%), and mucinous borderline tumor (18.4%) were frequently misinterpreted. Of 69 ovarian metastases, all 4 cases of low-grade appendiceal mucinous neoplasm (LAMN) were misdiagnosed as primary ovarian mucinous tumor. A literature review revealed that mucinous/serous borderline tumor or carcinoma accounted for approximately 70% of 217 reported discordant diagnoses.

CONCLUSION

In the present study, the concordance rate of malignant potential of the tumor was comparable to that previously reported. Even in the 2014 WHO classification, primary ovarian mucinous borderline tumor/carcinoma and LGSC still comprised the majority of discordant cases. Grossing methods that reduce sampling error are required. LAMN was frequently misinterpreted as a benign or borderline ovarian mucinous tumor. To prevent this error, a differential algorithm integrating clinical information and gross findings should be developed.

Incidental appendiceal mucinous neoplasm mimicking a left adnexal mass: A case report

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Equivocal signs and symptoms along with anatomical position of appendiceal mucinous neoplasm (AMN) makes it difficult to diagnose.

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Pre-operative, findings like ‘onion skin’ sign on ultrasonography and ‘volcano sign’ on colonoscopy are specific for appendiceal mucocele.

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Primary AMN is rarely diagnosed before operation and histopathological examination.

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AMN can mimic ovarian tumors. Consider AMN in the differential diagnosis for any pelvic mass in elderly female patients.

Introduction

Appendiceal mucinous neoplasm is a rare type of appendiceal tumors which can present in a variety of symptoms and is difficult to diagnose. Preoperative diagnosis depends mainly on diagnostic imaging such as ultrasonography and computerized tomography (CT) scan. This uncommon case report discusses an appendiceal mucinous neoplasm mimicking a left adnexal mass on presentation, physical examination and diagnostic imaging findings.

Presentation of case

This is a 61-year-old female found to have a large left adnexal mass during follow up ultrasonography. The patient refused further imaging, and during laparotomy, she was found to have an appendicular mucocele with normal left and right ovaries.

Discussion

Appendectomy was done and the final pathology came as appendiceal mucinous neoplasm. Her post-operative course and 3 years follow up were uneventful.

Conclusions

The equivocal signs and symptoms along with the anatomical position of appendiceal mucocele makes it difficult to diagnose and can mimic other types of tumors. Therefore, it should be considered in the deferential diagnosis of lower abdominal and pelvic masses.

Analysis of Clinical Characteristics of Low-Grade Appendiceal Mucinous Neoplasm (LAMN): A Retrospective Cohort Study of 51 LAMN Patients

INTRODUCTION

Low-grade appendiceal mucinous neoplasm (LAMN) is a rare disorder. There is no consensus on the prognosis and management of LAMN.

MATERIALS AND METHODS

We reviewed 51 consecutive patients with LAMN from 2013 to 2018. We divided our patients into two groups. The first is patients with an intact appendix. The second group comprises patients with the potential to develop a malignant condition. Comparisons of serum tumor markers between two groups were performed. Survival curves were estimated. Univariate and multivariate Cox proportional hazards were computed for 46 patients with median follow-up of 2.7 years.

RESULTS

Comparison of patients in two groups revealed significant differences in the mean level and abnormal ratio of CA125 (p < 0.001, p < 0.001), CA19-9 (p = 0.04, p = 0.04), and CEA (p = 0.001, p = 0.02). Eight patients had relapsed by the last follow-up in the second group. Patients with normal CEA had significantly longer disease-free survival (DFS) time than those with abnormal CEA (p = 0.04). CA19-9 exhibited a significant association with DFS (HR = 5.72, p = 0.02) in the Univariate Cox proportional hazards.

DISCUSSION

The prognosis of LAMN is related to serum tumor markers, the surgical procedure and the pathology.

Primary appendiceal mucinous neoplasm: Gynecological manifestations, management, and prognosis

OBJECTIVE

The aim of this study was to investigate the clinicopathological characteristics, management, and survival of patients with appendiceal mucinous neoplasm misdiagnosed as ovarian tumor and initially treated by a gynecological oncologists.

METHODS

We retrospectively reviewed data for 71 patients identified from January 1, 2006 to September 31, 2018 with a final pathological diagnosis of appendiceal mucinous neoplasm. All patients were diagnosed as having ovarian tumor preoperatively and initially treated at Department of Gynecological Oncology.

RESULTS

The median patients' age was 61 years, and the median peritoneal cancer index (PCI) was 16, with a complete cytoreduction score (CCR0/1) achieved in 46.47% of patients. Two patients received hyperthermic intraperitoneal chemotherapy (HIPEC). Estimated 5-year and 10-year survival was 76.7% and 53.4%, respectively. PCI and lactate dehydrogenase (LDH) levels were identified as independent predictors of poor overall survival.

CONCLUSIONS

Because of the high rate of ovarian metastases and the difficulty diagnosing appendiceal mucinous neoplasm preoperatively, this condition should be highlighted in gynecological oncology. Because initial surgical intervention is often performed by gynecological oncologists, updating the management guidelines for appendiceal mucinous tumor is needed because the rates of CCR0/1 resection and HIPEC are much lower in patients who are misdiagnosed.