Appendiceal adenocarcinoid with ovarian metastasis

Clinical, surgical, and pathological findings in client-owned rabbits with histologically confirmed appendicitis: 19 cases (2015-2019)

OBJECTIVE

To report clinical, surgical, and pathological findings in client-owned rabbits with histologically confirmed appendicitis.

ANIMALS

19 rabbits.

PROCEDURES

Medical records for client-owned rabbits that had a histologic diagnosis of appendicitis were reviewed.

RESULTS

Median age of the rabbits at presentation was 24.0 months (range, 4 to 84 months). Seventeen cases occurred during the summer and fall seasons. Decreased appetite (17/19 rabbits), abnormal rectal temperature (hyperthermia, 9/16 rabbits; hypothermia, 4/16 rabbits), hypocalcemia (8/11 rabbits), and hypoglycemia (7/15 rabbits) were common signs. Abdominal ultrasonography and CT findings were suggestive of appendicitis in 6 of 8 rabbits and in 1 of 2 rabbits, respectively. Of the 6 rabbits that received medical treatment, 3 died at 48 hours, 1 died at 24 hours after hospitalization, and 1 died at 10 days after presentation; 1 rabbit was alive at 1,030 days after presentation. Of the 8 rabbits that underwent appendectomy, 3 died before discharge from the hospital and 1 died 113 days after surgery; 4 rabbits were alive at 315, 334, 1,433, and 1,473 days after presentation. The remaining 5 rabbits either died or were euthanized before treatment could be instituted. In each of the 19 rabbits, the appendix had evidence of severe inflammation with mucosal ulceration, heterophilic inflammation, and necrotic debris.

CLINICAL RELEVANCE

For rabbits with decreased appetite and an apparently painful abdomen, hyperthermia, hypocalcemia, or hypoglycemia, appendicitis should be considered as a differential diagnosis. Further comparisons of medical and surgical treatments are required to establish treatment recommendations for rabbits with appendicitis.

Prevalence of Carcinoma in Appendectomy Specimens for Patients Presenting With Acute Appendicitis: A Single-Center Study

Introduction Acute appendicitis is the most common general surgical emergency globally. Its etiology includes the presence of luminal obstruction by faecoliths, lymphoid hyperplasia, impacted stool, and rarely by appendiceal or caecal cancer. Malignancy related to acute appendicitis is usually seen in the older age group. Aim To identify the subset rate of patients operated for acute appendicitis who have appendiceal carcinoma and analyze the outcome of their post-operative management. Material and methods A retrospective study of a cohort of 529 patients aged > 40 diagnosed with acute appendicitis with subsequent appendectomy in the period between 1 January 2014 and 31 December 2019 at Basildon and Thurrock University Hospital, Essex, United Kingdom was conducted. We analyzed the clinical data of the cohort including demographic information, diagnosis, pre-operative imaging, histological diagnosis as well as post-operative management where indicated. Results The median age of patients was 54.5 years (range 40-92). The male to female ratio in the appendicectomy cohort was 1:1.1. About 45% were aged 40-49 years, 24.8% were aged 50-59 and 30.2% were ≥60 years. Post-operative histology revealed acute appendicitis in 82.4% of the group. In 11% of the patients, the histology revealed the presence of other benign pathology as mucocele of the appendix, acute diverticulitis, follicular hyperplasia, and fibrous obliteration. The diagnosis of appendicular malignancy was seen in 1.9%. Conclusion Incidental appendiceal cancers in the resected specimens after acute appendicitis are rare but may be associated with a poor prognosis. It is recommended to consider such diagnosis in particular when dealing with acute appendicitis in older patients with longer symptom history, and in presence of peri-appendicular mass.

Exosomal proteomic signatures correlate with drug resistance and carboplatin treatment outcome in a spontaneous model of canine osteosarcoma

BACKGROUND

Osteosarcoma patients often experience poor outcomes despite chemotherapy treatment, likely due in part to various mechanisms of tumor cell innate and/or acquired drug resistance. Exosomes, microvesicles secreted by cells, have been shown to play a role in drug resistance, but a comprehensive protein signature relating to osteosarcoma carboplatin resistance has not been fully characterized.

METHODS

In this study, cell lysates and exosomes from two derivatives (HMPOS-2.5R and HMPOS-10R) of the HMPOS osteosarcoma cell line generated by repeated carboplatin treatment and recovery, were characterized proteomically by mass spectrometry. Protein cargos of circulating serum exosomes from dogs with naturally occurring osteosarcoma, were also assessed by mass spectrometry, to identify biomarkers that discriminate between good and poor responders to carboplatin therapy.

RESULTS

Both cell lysates and exosomes exhibited distinct protein signatures related to drug resistance. Furthermore, exosomes from the resistant HMPOS-2.5R cell line were found to transfer drug resistance to drug-sensitive HMPOS cells. The comparison of serum exosomes from dogs with a favorable disease-free interval [DFI] of > 300 days, and dogs with < 100 days DFI revealed a proteomic signature that could discriminate between the two cohorts with high accuracy. Furthermore, when the patient's exosomes were compared to exosomes isolated from carboplatin resistant cell lines, several putative biomarkers were found to be shared.

CONCLUSIONS

The findings of this study highlight the significance of exosomes in the potential transfer of drug resistance, and the discovery of novel biomarkers for the development of liquid biopsies to better guide personalized chemotherapy treatment.

Goblet cell carcinoid tumor, mixed goblet cell carcinoid-adenocarcinoma, and adenocarcinoma of the appendix: comparison of clinicopathologic features and prognosis

CONTEXT

The prognosis of appendiceal goblet cell carcinoid tumors (GCTs) is believed to be intermediate between appendiceal adenocarcinomas and conventional carcinoid tumors. However, GCTs can have mixed morphologic patterns, with variable amount of adenocarcinoma.

OBJECTIVE

To evaluate the behavior of GCTs and related entities with variable components of adenocarcinoma.

DESIGN

We classified 74 cases of appendiceal tumors into 3 groups: group 1, GCTs or GCTs with less than 25% adenocarcinoma; group 2, GCTs with 25% to 50% adenocarcinoma; group 3, GCTs with more than 50% adenocarcinoma; and a comparison group of 68 adenocarcinomas without a GCT component (group 4). Well-differentiated mucinous adenocarcinomas were excluded. Clinicopathologic features and follow-up were obtained from computerized medical records and the US Social Security Death Index.

RESULTS

Of the 142 tumors studied, 23 tumors (16%) were classified as group 1; 27 (19%) as group 2; 24 (17%) as group 3; and 68 (48%) as group 4. Staging and survival differed significantly among these groups. Among 140 patients (99%) with available staging data, stages II, III, and IV were present in 87%, 4%, and 4% of patients in group 1 patients; 67%, 7%, and 22% of patients in group 2; 29%, 4%, and 67% of patients in group 3; and 19%, 6%, and 75% of patients in group 4, respectively (P = .01). Mean (SD) overall survival was 83.8 (34.6), 60.6 (30.3), 45.6 (39.7), and 33.6 (27.6) months for groups 1, 2, 3, and 4, respectively (P = .01). By multivariate analysis, only stage and tumor category were independent predictors of overall survival.

CONCLUSION

Our data highlight the importance of subclassifying the proportion of adenocarcinoma in appendiceal tumors with GCT morphology because that finding reflects disease stage and affects survival.

Autotransplantation of cryopreserved ovarian tissue in cancer survivors and the risk of reintroducing malignancy: a systematic review

BACKGROUND The risk of recurrent oncological disease due to the reintroduction of cancer cells via autotransplantation of cryopreserved ovarian tissue is unknown. METHODS A systematic review of literature derived from MEDLINE, EMBASE and the Cochrane Library was conducted. Studies on follow-up after autotransplantation; detection of cancer cells in ovarian tissue from oncological patients by histology, polymerase chain reaction or xenotransplantation; and epidemiological data on ovarian metastases were included. RESULTS A total of 289 studies were included. Metastases were repeatedly detected in ovarian tissue obtained for cryopreservation purposes from patients with leukaemia, as well as in one patient with Ewing sarcoma. No metastases were detected in ovarian tissue from lymphoma and breast cancer patients who had their ovarian tissue cryopreserved. Clinical studies indicated that one should be concerned about autotransplantation safety in patients with colorectal, gastric and endometrial cancer. For patients with low-stage cervical carcinoma, clinical data were relatively reassuring, but studies focused on the detection of metastases were scarce. Oncological recurrence has been described in one survivor of cervical cancer and one survivor of breast cancer who had their ovarian tissue autotransplanted, although these recurrences may not be related to the transplantation. CONCLUSIONS It is advisable to refrain from ovarian tissue autotransplantation in survivors of leukaemia. With survivors of all other malignancies, current knowledge regarding the safety of autotransplantation should be discussed. The most reassuring data regarding autotransplantation safety were found for lymphoma patients.

Goblet cell carcinoids of the appendix

Goblet cell carcinoid (GCC) tumors are a rare subgroup of neuroendocrine tumors almost exclusively originating in the appendix. The tumor most often presents in the fifth or sixth decade with a clinical picture of appendicitis or in advanced cases an abdominal mass associated with abdominal pain. Histologically tumors are most often positive for chromogranin A and synaptophysin, however, less homogenous than for classic appendix carcinoids. The malignant potential is higher than that for the classic appendix carcinoids due to local spread and distant metastases at diagnosis and the proliferation markers (Ki67 index) may determine prognosis. Octreotide receptor scintigraphy is usually negative while CT/MRI scans may be useful. Chromogranin A is usually negative and other biomarkers related to the mucinous component or the tumor (CEA, CA-19-9, and CA-125) may be used. Surgery is the main treatment with appendectomy and right hemicolectomy while patients with disseminated disease should be treated with chemotherapy. Overall 5-year survival is approximately 75%. The diagnosis and treatment of GCC tumorss should be restricted to high volume NET centers in order to accumulate knowledge and improve survival in GCC NET patients. The aim of this paper is to update on epidemiology, clinical presentation, and diagnostic markers including Ki67 index, treatment, and survival.

Malignant neoplasms of the appendix

BACKGROUND

Appendiceal neoplasms, first described in 1882, are still rare, with pre-operative diagnosis invariably difficult. We present our 10-year experience of these lesions with a review of current epidemiology, pathology and treatment modalities.

MATERIALS AND METHODS

A retrospective histopathological review of all appendicectomy specimens was completed between April 1994 and December 2003 to identify patients diagnosed with malignant neoplasms. Patient demographics, operative details, histopathology and clinical outcomes were obtained from case notes. A literature search of the PubMed database was then performed using the medical search headings; appendix, tumour, neoplasm and malignancy.

RESULTS

Twenty-two patients (eight men) were identified during the study period, with no age difference between gender (mean age in women 58, range 14-83 vs mean age in men 55, range 16-78). Eleven patients were found to have carcinoid-type tumours, eight patients with adenocarcinomas and three patients with lymphomas. Other appendiceal pathologies were identified after appendicectomies, hemicolectomy and oophorectomy. Mean follow-up was 41 months (range 1-125 months). Fourteen patients were alive at the end of follow-up. Patients with classical carcinoid tumours (CCT) had better outcomes than patients with the goblet cell carcinoid, adenocarcinoma and lymphoma.

CONCLUSIONS

From our own experience and a subsequent review of the literature, we recommend right hemicolectomy as the treatment of choice for all malignant appendiceal neoplasms, except for small CCT less than 2 cm in diameter at the tip of the appendix, with a low proliferative index, without angiolymphatic or mesoappendiceal extension. Further adjuvant therapy should be considered after oncological assessment.

Ovarian Metastases of Appendiceal Tumors With Goblet Cell Carcinoidlike and Signet Ring Cell Patterns

Synchronous and metachronous ovarian and appendiceal mucinous tumors are often the subject of diagnostic consultations in gynecologic pathology practices to address whether the tumors are independent neoplasms or related as primary and metastasis. Those with goblet cell carcinoidlike patterns have not been extensively evaluated in a large series. Clinicopathologic features of 30 cases were examined. All patients presented with signs or symptoms related to a pelvic/adnexal or abdominal mass. The ovarian tumors were bilateral in 25 of 28 cases with data on both ovaries and were typically large (mean/median: 14 cm, range: 4.5 to 24.0 cm). The appendices were often firm or thickened but usually did not have a discrete measurable tumor and were not notably enlarged; microscopically, transmural invasion was present in all of them. The ovarian and appendiceal tumors exhibited a variety of patterns of differentiation, including signet ring cell and glandular, with all displaying some goblet cell carcinoidlike patterns (nests, islands, cords, or cryptlike tubules with goblet cells); teratomatous elements were not identified in any ovarian tumors. Chromogranin was expressed in 7 of 19 ovarian tumors (mean/median: 6.3%/0%; range: 0% to 20%) and synaptophysin was expressed in 4 of 18 of these (mean/median: 7.8%/0%; range: 0% to 90%). Chromogranin was expressed in 6 of 16 appendiceal tumors (mean/median: 11.9%/0%; range: 0% to 70%) and synaptophysin was expressed in 6 of 15 of these (mean/median: 16.7%/0%; range: 0% to 90%). Follow-up was available for 25 patients: 17 died of disease at intervals ranging from 4 to 47 months (mean/median: 18/16) and 8 were alive with disease at 1 to 25 months (mean/median: 11/10); median survival was 19 months and the 1-year and 2-year survival rates were 63% and 34%, respectively. The clinicopathologic features of these ovarian tumors indicate they should be labeled as metastatic appendiceal adenocarcinomas rather than as goblet cell carcinoid tumors both to reflect their behavior and help distinguish them from the rare true primary ovarian goblet cell carcinoid tumors. As the ovarian tumors have appreciable components of signet ring cells they qualify as Krukenberg tumors. In cases in which the primary tumor is not already evident, their "goblet cell carcinoidlike" patterns should direct attention to the appendix as a possible source.

Surgical treatment of malignant carcinoid tumours of the appendix

Since their first description in 1882, malignant neoplasms of the appendix still remain rare. Malignant carcinoid tumours are the most common accounting for 85% of all appendiceal neoplasms. Preoperative diagnosis is invariably difficult, and precise treatment protocols for these neoplasms remain unclear. We reviewed our experience and searched published evidence to produce management guidelines. A retrospective review of all malignant carcinoid tumours diagnosed in our hospital between April 1994 and December 2003 was performed. Patient demographics, operative details, histological types and clinical outcomes were retrieved from case notes supplemented by a questionnaire to the patient's General Practitioner. A literature search was then performed. Nine patients were identified with classical carcinoid tumours (CCT); (M = 3 and F = 6, mean age: 43, range 14-81) and two patients with goblet-cell morphology (F = 2, age 46 and 76). Mean follow-up was 63 months (range 1-125 months). Nine patients were alive at the end of follow-up. Appendicectomy was performed for acute appendicitis. Other appendiceal pathologies were identified following hemicolectomy and oophorectomy. CCT are the most common tumours and have the better prognosis. From our experience and subsequent review of the literature, we recommend right hemicolectomy as the treatment of choice for malignant carcinoid tumours. However, small CCTs less than 2 cm in diameter at the tip of the appendix, with a low proliferative index, without angiolymphatic or mesoappendiceal extension can be treated by appendicectomy. Following oncological assessment, further adjuvant therapy should be considered for patients with advanced disease.

Management of goblet cell carcinoid

BACKGROUND AND OBJECTIVES

Goblet cell carcinoid, a rare tumor of intermediate malignant potential, is known to account for a significant minority of appendiceal neoplasms. Sixteen new cases of gastrointestinal goblet cell carcinoid were reviewed to describe their presentation, treatment, and outcome.

METHODS

A review of 16 cases from a single institution.

RESULTS

Sixteen patients were diagnosed with goblet cell carcinoid between 1995 and 2005. Presenting diagnoses included appendicitis (n=8), abdominal or liver mass (n=5), uterine fibroids (n=1), ovarian mass (n=1), and Crohn's Disease exacerbation (n=1). Mean follow-up was 12 months with a mortality of 19% (n=3). Patients were divided into two groups: those where the diagnosis was an incidental finding at operation (Group 1) and those where the presentation was of an abdominal mass or metastatic disease (Group 2). Nine of ten patients in Group 1 initially received appendectomies. Group 2 included patients presenting with Krukenberg type lesions (n=2) and abdominal masses (n=4).

CONCLUSIONS

Goblet cell carcinoid is a rare malignant tumor largely affecting the appendix. In patients presenting with appendicitis, our series does not support the recommendation of right hemicolectomy based on pathologic diagnosis alone and surgical intervention must be customized to the individual patient.

Krukenberg tumor from an occult appendiceal adenocarcinoid: a case report and review of the literature

Appendiceal neoplasms with ovarian metastasis are rare. A 35-year-old woman with a left ovarian tumor underwent left salpingo-oophorectomy, partial resection of the right ovary, and a total hysterectomy. Pathological diagnosis of both ovaries was typical, Krukenberg tumor with signet-ring cells, and the second laparotomy revealed an occult appendiceal tumor to be the primary lesion. The appendix showed no evidence of malignant change of the mucosa, but the tumor cells were observed infiltrating from the basiglandular region into the underlying stroma, associated with mucocele. Although, argentaffin and argyrophil staining were negative, a few tumor cells showed immunohistochemical positivity for Chromogranin A. Accordingly, the tumor was diagnosed as adenocarcinoid rather than adenocarcinoma of the appendix. A review of the literature showed less than 40 cases of metastatic ovarian tumor from appendiceal primary, one-third of which were occult and could be detected at the second laparotomy. Cisplatin-based chemotherapy may have partial effect in the treatment of patient with adenocarcinoid tumor.

Ovarian mucinous carcinoids including some with a carcinomatous component: a report of 17 cases

Only rare primary mucinous (goblet cell) carcinoids of the ovary have been reported, and their clinicopathologic features have not been well delineated. The authors studied 17 examples from patients 14 to 74 years of age. The clinical presentations were similar to those of ovarian neoplasms in general. The tumors ranged from 0.8 to 30 cm in diameter. In six cases the tumor was in the wall of a mature cystic teratoma, appearing grossly as solid nodules or areas of thickening in four of them, six tumors were entirely solid, and five were solid associated with other types of cystic tumor. The tumors were divided into three groups on the basis of their microscopic features. Six neoplasms, designated "well differentiated," were composed of small glands, many of which floated in pools of mucin. The glands were lined by goblet cells and columnar cells, some of which were of neuroendocrine type. Three tumors, designated "atypical," were characterized by crowded glands, some of which were confluent, small islands with a cribriform pattern, and scattered microcystic glands. The glands were lined by cuboidal to columnar cells, some of them neuroendocrine, admixed with goblet cells. Eight tumors, designated "carcinoma arising in mucinous carcinoid," contained islands and larger nodules of tumor cells, or closely packed glands, as well as single cells, mainly of the signet ring cell type. Most of the cells were devoid of mucin and were severely atypical with marked mitotic activity. Necrosis was present in all eight tumors. Seven of the eight tumors with a carcinomatous component contained at least minor foci of well-differentiated mucinous carcinoid; the eighth contained only foci of atypical mucinous carcinoid. The neuroendocrine nature of a variable proportion of the cells in all three groups was demonstrated by staining for neuroendocrine markers. The mucinous nature of other cells was confirmed by mucicarmine or Alcian blue stains. The ovary contained an intrinsic component of trabecular and insular carcinoid, and of strumal carcinoid in one case each, an adjacent mature cystic teratoma in six cases, mucinous cystadenocarcinoma in three cases, and borderline mucinous cystic tumor, borderline Brenner tumor, and epidermoid cyst in one case each. Fifteen tumors were stage I, one was stage II, and one was stage III. The last two tumors had a carcinomatous component. Follow-up data were available for 15 patients; 12 were alive and free of tumor 2.3 to 14 years (average, 4.7 years) after the ovarian tumor was excised. One patient, whose tumor had a carcinomatous component, died 3 years postoperatively of unrelated causes. Two patients, both of whom had a carcinomatous component in their tumor, died 9 and 12 months postoperatively. Primary mucinous carcinoids must be distinguished from metastatic mucinous carcinoid tumors from the appendix or elsewhere. Features supporting an ovarian origin are the additional presence in the specimen of teratoma or an ovarian surface epithelial tumor, an absence of blood vessel or lymphatic space invasion, and confinement to a single ovary. Similar features help to distinguish mucinous carcinoids from Krukenberg tumors. Mucinous carcinoids should also be distinguished from strumal carcinoids, which can contain mucinous glands, and insular carcinoid tumors that arise rarely in the wall of a mucinous cystic neoplasm. Although the number of cases in this series is small, the follow-up data suggest that the degree of differentiation, particularly the presence of frank carcinoma, is an important prognostic factor.

Primary appendiceal malignancy mimicking advanced stage ovarian carcinoma: a case series

BACKGROUND

Primary appendiceal malignancy metastatic to the ovaries is a rare condition that may mimic late stage ovarian cancer. This condition is rarely diagnosed preoperatively.

CASES

Three patients referred to our institution from 1994 to 1999 for presumed late stage ovarian cancer were found to have primary appendiceal adenocarcinoma, adenocarcinoid, and mucinous cystadenocarcinoma metastatic to the ovaries at laparotomy. We describe the clinical course of these patients and review the relevant literature.

CONCLUSION

It is important for the gynecologic oncologist to be aware of the clinicopathological features and surgical management of these malignancies, as the incidence, prognosis, and recommended treatment vary with histological subtype.

K-ras and p53 mutations in the pathogenesis of classical and goblet cell carcinoids of the appendix

BACKGROUND

Mutations in the K-ras oncogene and the p53 tumor suppressor gene are present in approximately 50% of colonic adenocarcinomas. Goblet cell carcinoids (GCCs) are uncommon neoplasms of the appendix that appear to be intermediate between carcinoid tumors and adenocarcinomas, both histologically and biologically. The current study was undertaken to examine the role of p53 and K-ras mutations in the pathogenesis of GCCs and typical carcinoids (TCs) of the appendix.

METHODS

Archival materials from 22 GCCs and 18 TCs were analyzed. K-ras mutations in codons 12, 13, and 61 were studied by a polymerase chain reaction (PCR) based designed restriction fragment length polymorphism method using mismatched nested primers. Mutations in exons 5-8 of the p53 tumor suppressor gene were analyzed in 16 GCCs and 18 TCs by PCR and single-strand conformational polymorphism followed by direct sequencing. Immunostains for p53 and chromogranin were performed in all cases.

RESULTS

K-ras mutations and nuclear accumulation of p53 by immunohistochemistry were not detected in any of the GCCs or TCs. p53 mutations were found in 4 of 16 GCCs (25%) and 8 of 18 TCs (44%). Immunoreactivity for chromogranin was seen in the vast majority of GCCs and TCs.

CONCLUSIONS

p53 mutations appear to play a role in the pathogenesis of some GCCs and in approximately 50% of TCs of the appendix, whereas mutations in the K-ras oncogene do not appear to be important in the development of these tumors. The minimal cytologic atypia, low incidence of metastases, and lack of K-ras mutations in goblet cell appendiceal neoplasms suggest that they are variants of carcinoid tumors. Our findings lend support to the recommendation that the therapeutic guidelines applied to TCs of the appendix should be the same for GCCs.

The morphologic spectrum of ovarian metastases of appendiceal adenocarcinomas: a clinicopathologic and immunohistochemical analysis of tumors often misinterpreted as primary ovarian tumors or metastatic tumors from other gastrointestinal sites

Twenty cases of ovarian metastases derived from appendiceal adenocarcinomas were analyzed. The most common presentation was a pelvic mass. The appendiceal and ovarian tumors were diagnosed concurrently in 15 cases; in the remaining five, the ovarian tumors were diagnosed before the appendiceal tumor. The appendiceal adenocarcinomas demonstrated four morphologic patterns: 1) signet ring cell type, with or without glandular or goblet cell differentiation (14 cases); 2) mixed signet ring cell and intestinal type (two cases); 3) intestinal type (two cases); and 4) typical colorectal type (two cases). The ovarian tumors were bilateral in 16 cases and were histologically similar to the associated appendiceal tumor in each case. Ovarian metastases that demonstrate signet ring cell, glandular, and goblet cell differentiation mimic metastases from gastric adenocarcinoma. Those that are derived from well-differentiated mucinous appendiceal adenocarcinomas mimic primary ovarian mucinous tumors and metastases from the pancreas and biliary tract. Metastases of appendiceal adenocarcinomas of colorectal type simulate both metastatic colorectal carcinoma and primary ovarian endometrioid carcinomas. The appendiceal and ovarian tumors were immunophenotypically identical in each case. Approximately 50% of the appendiceal and ovarian tumors were positive for cytokeratin 7 (CK 7), and all were positive for cytokeratin 20 (CK 20). CK 20 positivity of the ovarian tumors is consistent with gastrointestinal origin; CK 7 positivity does not confirm ovarian origin, because appendiceal carcinomas are positive in 50% of cases. Metastatic appendiceal adenocarcinoma should be considered in the differential diagnosis of mucinous ovarian tumors with signet ring cell, goblet cell, or intestinal type differentiation, especially when these tumors are associated with extraovarian disease and are bilateral.