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Hissong E. Exploring the mysterious mucinous appendiceal neoplasm. Semin Diagn Pathol 2024:S0740-2570(24)00067-4. [PMID: 39183113 DOI: 10.1053/j.semdp.2024.08.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 07/11/2024] [Accepted: 08/07/2024] [Indexed: 08/27/2024]
Abstract
Mucinous neoplasms of the appendix comprise a group of diagnostically challenging lesions that have generated significant controversy and confusion throughout the years, given their potential for aggressive behavior despite very bland cytologic features. Numerous classification schemes have been proposed to characterize and stage these lesions, but confusion remains among pathologists, surgeons, and oncologists regarding diagnostic criteria, therapeutic implications, and overall prognosis. This review summaries the current recommended nomenclature, histologic characteristics of each entity, and helpful features to distinguish neoplasia from benign mimics.
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Affiliation(s)
- Erika Hissong
- New York Presbyterian Hospital, Weill-Cornell Medicine, 525 E 68th St, New York, NY 10065, USA.
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Requena DO, Yantiss RK. A practical guide to serrated appendiceal lesions. Semin Diagn Pathol 2024:S0740-2570(24)00066-2. [PMID: 39084918 DOI: 10.1053/j.semdp.2024.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 07/09/2024] [Indexed: 08/02/2024]
Abstract
Several neoplastic and non-neoplastic proliferations of the appendix can show varying degrees of serrated epithelial architecture. Of these, diffuse mucosal hyperplasia is most common, followed in frequency by low-grade mucinous and serrated neoplasms. It is important to distinguish serrated appendiceal neoplasms from their potential mimics because these entities may be managed differently. Diffuse mucosal hyperplasia is a non-neoplastic change that usually develops in the setting of resolving appendicitis and requires no further therapy or surveillance, and serrated neoplasms confined to the mucosa are adequately treated by appendectomy alone. On the other hand, low-grade appendiceal mucinous neoplasms may require surveillance, and those with extra-appendiceal spread differ from adenocarcinomas arising from serrated neoplasms with respect to both treatment and prognosis. Low-grade mucinous neoplasms in the peritoneum are frequently amenable to peritoneum-directed therapies alone, while adenocarcinomas derived from serrated neoplasms often spread to both regional lymph nodes and the peritoneum, potentially requiring right colectomy and systemic chemotherapy. The purpose of this review is to summarize the literature regarding the clinical and pathologic features of appendiceal lesions that show epithelial serration and provide the reader with helpful tips to distinguish serrated neoplasms from their mimics.
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Affiliation(s)
- Domenika Ortiz Requena
- Department of Pathology and Laboratory Medicine, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Rhonda K Yantiss
- Department of Pathology and Laboratory Medicine, University of Miami Miller School of Medicine, Miami, FL, United States.
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Dartigues P. [Histoseminar tumoral peritoneal biopsies. Appendicular mucinous neoplasia]. Ann Pathol 2024; 44:274-290. [PMID: 38981795 DOI: 10.1016/j.annpat.2024.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 06/04/2024] [Accepted: 06/12/2024] [Indexed: 07/11/2024]
Affiliation(s)
- Peggy Dartigues
- Département d'anatomie et cytologie pathologiques - Gustave-Roussy, 114, rue Édouard-Vaillant, 94805 Villejuif, France.
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Chetty R. Serrated and mucinous appendiceal lesions: a viewpoint. J Clin Pathol 2024; 77:452-456. [PMID: 38772615 DOI: 10.1136/jcp-2024-209554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 05/01/2024] [Indexed: 05/23/2024]
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Clinicopathologic parameters and outcomes of mucinous neoplasms confined to the appendix: a benign entity with excellent prognosis. Mod Pathol 2022; 35:1732-1739. [PMID: 35676331 DOI: 10.1038/s41379-022-01114-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/16/2022] [Accepted: 05/17/2022] [Indexed: 11/09/2022]
Abstract
Appendiceal mucinous neoplasms (AMNs), characterized by expansile or "pushing" growth of neoplastic epithelium through the appendix wall, are sometimes accompanied by peritoneal involvement, the extent and grade of which largely determine clinical presentation and long-term outcomes. However, the prognosis of tumors entirely confined to the appendix is still debated and confusion remains regarding their biologic behavior and, consequently, their clinical management and even diagnostic nomenclature. We evaluated AMNs limited to the appendix from 337 patients (median age: 58 years, interquartile range (IQR): 47-67), 194 (57.6%) of whom were women and 143 (42.4%) men. The most common clinical indication for surgery was mass or mucocele, in 163 (48.4%) cases. Most cases (N = 322, 95.5%) comprised low-grade epithelium, but there were also 15 (4.5%) cases with high-grade dysplasia. Lymph nodes had been harvested in 102 (30.3%) cases with a median 6.5 lymph nodes (IQR: 2-14) per specimen for a total of 910 lymph nodes examined, all of which were negative for metastatic disease. Histologic slide review in 279 cases revealed 77 (27.6%) tumors extending to the mucosa, 101 (36.2%) to submucosa, 33 (11.8%) to muscularis propria, and 68 (24.4%) to subserosal tissues. In multivariate analysis, deeper tumor extension was associated with older age (p = 0.032; odds ratio (OR): 1.02, 95% confidence intervals (CI): 1.00-1.03), indication of mass/mucocele (p < 0.001; OR: 2.09, CI: 1.41-3.11), and wider appendiceal diameter, grossly (p < 0.001; OR: 1.61, CI: 1.28-2.02). Importantly, among 194 cases with at least 6 months of follow-up (median: 56.1 months, IQR: 24.4-98.5), including 9 high-grade, there was no disease recurrence/progression, peritoneal involvement (pseudomyxoma peritonei), or disease-specific mortality. These data reinforce the conclusion that AMNs confined to the appendix are characterized by benign biologic behavior and excellent clinical prognosis and accordingly suggest that revisions to their nomenclature and staging would be appropriate, including reverting to the diagnostic term mucinous adenoma in order to accurately describe a subset of them.
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Malvar G, Peric M, Gonzalez R. Interval appendicitis shows histologic differences from acute appendicitis and may mimic Crohn disease and other forms of granulomatous appendicitis. Histopathology 2022; 80:965-973. [DOI: 10.1111/his.14621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 01/13/2022] [Accepted: 01/20/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Grace Malvar
- Department of Pathology Beth Israel Deaconess Medical Center
| | - Masa Peric
- Department of Pathology Beth Israel Deaconess Medical Center
| | - Raul Gonzalez
- Department of Pathology Beth Israel Deaconess Medical Center
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Orr CE, Yantiss RK. Controversies in appendiceal pathology: Mucinous and goblet cell neoplasms. Pathology 2021; 54:167-176. [PMID: 34836648 DOI: 10.1016/j.pathol.2021.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/23/2021] [Accepted: 09/02/2021] [Indexed: 12/26/2022]
Abstract
Appendiceal goblet cell adenocarcinomas and mucinous neoplasms are uncommon compared with other epithelial tumours of the gastrointestinal tract. Both tumour types have been subjected to terminology that belies their biological risk and leads to confusion. Goblet cell adenocarcinomas display patchy staining for endocrine markers and, thus, were previously classified as goblet cell carcinoids. Unlike well-differentiated endocrine neoplasms, however, they often contain high-grade glandular elements and pursue an aggressive course akin to that of conventional adenocarcinoma. Although several authors have recently proposed grading schemes to predict behaviour among goblet cell neoplasms, most that contain high-grade components have already spread beyond the appendix at the time of diagnosis, whereas those confined to the appendix almost always have low-grade features; the added value of grading these tumours is limited. Contradictions also surround the nomenclature of mucinous neoplasms. The World Health Organization and others promote non-malignant terminology to describe metastatic mucinous neoplasms of the peritoneum and eliminate a benign category entirely, even though virtually all neoplasms confined to the appendix pose no recurrence risk following appendectomy. 'Low-grade appendiceal mucinous neoplasm' now encompasses a spectrum of benign tumours and malignant neoplasms in the appendix and peritoneum. Although using an umbrella term in this fashion simplifies the roles of pathologists, it provides essentially no actionable information beyond that which is already clinically apparent. Broad strokes nomenclature also ensures that many patients with no risk of recurrence will receive unnecessary surveillance while others will undergo inappropriate surgical procedures due to lapses in communication. Moreover, a surprising number of non-neoplastic mucinous lesions are misclassified as low-grade appendiceal mucinous neoplasms, which can result in unwarranted patient concern or even mismanagement. The purpose of this review is to critically evaluate the literature and describe an approach to appendiceal neoplasms that more clearly denotes their biologic risk.
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Affiliation(s)
- Christine E Orr
- Department of Pathology and Molecular Medicine, Queen's University, Kingston, ON, Canada
| | - Rhonda K Yantiss
- Department of Pathology and Laboratory Medicine, Weill Cornell Medicine, New York, NY, USA.
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The Frontiers of Appendiceal Controversies: Mucinous Neoplasms and Pseudomyxoma Peritonei. Am J Surg Pathol 2021; 46:e27-e42. [PMID: 33417324 DOI: 10.1097/pas.0000000000001662] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Appendiceal mucinous neoplasms show a range of morphologic features and biological risk. At one end of the spectrum, high-grade adenocarcinomas are cytologically malignant with infiltrative invasion, lymph node metastases, and behavior similar to that of extra-appendiceal mucinous adenocarcinomas. At the other end, mucinous neoplasms confined to the mucosa are uniformly benign. Some cases lying between these extremes have potential risk to metastasize within the abdomen despite a lack of malignant histologic features. They show "diverticulum-like," pushing invasion of mostly low-grade epithelium through the appendix with, or without, concomitant organizing intra-abdominal mucin. The latter condition, widely termed "pseudomyxoma peritonei," tends to pursue a relentless course punctuated by multiple recurrences despite cytoreductive therapy, culminating in death for many patients. The combination of bland histologic features and protracted behavior of peritoneal disease has led some authors to question whether these metastatic tumors even represent malignancies. The World Health Organization and its cadre of experts widely promote usage of "low-grade appendiceal mucinous neoplasm" as an umbrella term to encompass benign and malignant conditions, as well as those that have uncertain biological potential. Although this practice greatly simplifies tumor classification, it causes confusion and consternation among pathologists, clinical colleagues, and patients. It also increases the likelihood that at least some patients will undergo unnecessary surveillance for, and treatment of, benign neoplasms and non-neoplastic conditions. The purpose of this review is to critically evaluate the relevant literature and discuss a practical approach to classifying appendiceal mucinous neoplasms that more closely approximates their biological risk.
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Ballentine SJ, Carr J, Bekhor EY, Sarpel U, Polydorides AD. Updated staging and patient outcomes in low-grade appendiceal mucinous neoplasms. Mod Pathol 2021; 34:104-115. [PMID: 32728224 DOI: 10.1038/s41379-020-0628-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/03/2020] [Accepted: 07/05/2020] [Indexed: 11/09/2022]
Abstract
Low-grade appendiceal mucinous neoplasms (LAMNs) exhibit drastically different clinical course and prognosis depending on tumor stage, particularly as it relates to the extent and cellularity of peritoneal involvement. In this context, recent changes in staging guidelines have sought to clarify criteria for pT and pM categories. This study's aim was to identify clinicopathological features associated with patient outcomes, especially as they pertain to updated stage groups. We reviewed LAMNs from 192 patients (mean age: 56.9 years, 119 (62.0%) women). The tumors consisted of 66 (34.4%) pTisM0, 16 (8.3%) pT3M0, 16 (8.3%) pT4aM0, 27 (14.1%) pTxM1a, and 67 (34.9%) pTxM1b cases. In multivariate analysis, only gross perforation was significantly associated with higher TNM group stage (p = 0.001; OR 3.3, 95% CI: 1.7-6.4). Of 165 (85.9%) patients with clinical follow-up, 51 (30.9%) had disease progression (over a mean 33.7 months, range: 4.7-121.7), whereas over significantly longer follow-up (mean 48.7 months, range: 3.1-143.9; p = 0.004), 114 (69.1%) patients did not. In multivariate analysis, higher TNM stage was significantly associated with disease progression (p = 0.029; OR 18.3, 95% CI: 1.4-246.0). In Kaplan-Meier analysis, none of 74 patients with disease limited to the appendix (pM0), 6 of 27 (22.2%) cases with peritoneal involvement by acellular mucin only (pM1a), and 45 of 64 (70.3%) tumors with intraperitoneal deposits containing neoplastic cells (pM1b) showed disease progression (p < 0.001). These differences in progression-free survival among TNM groups persisted when limiting the analysis to patients who had undergone successful cytoreductive surgery (p = 0.050). Finally, in four patients (all with pM1b disease) death was attributed to disease progression whereas there was no disease-specific mortality in the pM0 and pM1a groups (p = 0.020). These data support the designation of LAMNs with acellular peritoneal mucin as having an intermediate prognosis between cases limited to the appendix and those with intraperitoneal deposits containing neoplastic epithelium.
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Affiliation(s)
- Samuel J Ballentine
- Department of Pathology, Molecular and Cell-based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.,Department of Pathology and Immunology, Washington University in St. Louis School of Medicine, Saint Louis, MO, USA
| | - Jacquelyn Carr
- Department of Surgery, Division of Surgical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Eliahu Y Bekhor
- Department of Surgery, Division of Surgical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Umut Sarpel
- Department of Surgery, Division of Surgical Oncology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alexandros D Polydorides
- Department of Pathology, Molecular and Cell-based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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