低级别阑尾黏液性肿瘤35例临床病理特点分析

目的 探讨低级别阑尾黏液性肿瘤（LAMN）病人的临床病理特点,为临床诊治提供参考。方法 回顾性分析2013年3月至2019年3月期间于郑州大学第一附属医院就诊的35例LAMN病人的临床病理资料。 结果 35例LAMN病人中,男13例,女22例,年龄（57.7±12.4）岁。腹痛14例,发现腹部包块12例,腹胀6例,下肢水肿1例,消化道出血1例,体检发现1例。行术前超声检查18例,行术前下腹部增强CT检查26例。癌胚抗原（CEA）升高18例,CA19-9升高6例。LAMN病人与LAMN合并腹膜假黏液瘤（LAMN+PMP）病人CA19-9及CEA阳性率差异无统计学意义。7例行传统开放手术,28例行腹腔镜及腹腔镜辅助手术。其中10例行右半结肠切除,且淋巴结活检均未见转移。5例术中发现阑尾穿孔。随访期间肿瘤进展或复发5例,均为LAMN+PMP。 结论 肿瘤标记物联合影像学检查对LAMN的诊断及治疗有一定提示意义。阑尾穿孔或合并卵巢黏液肿瘤多见于LAMN+PMP,且LAMN预后优于LAMN+PMP。     

MDCT在胰腺导管内乳头状黏液瘤中的应用

胰腺导管内乳头状黏液瘤（intraductal papillary mueinotls neoplasm．IPMN）是一种少见的胰腺囊性肿瘤。根据世界卫生组织的定义．IPMN起源于胰腺主胰管或分支胰管内的导管上皮．向胰管内呈乳头状生长并分泌大量黏液．进而导致胰管扩张或囊性灶形成。IPMN具有潜在恶变可能．可由良性腺瘤逐步进展为交界性肿瘤、原位癌或浸润性腺癌．前二者预后相对较好,而一旦发展为浸润性腺癌．则预后较差。     

胰腺黏液性囊性肿瘤诊治分析

目的 探讨胰腺黏液性囊性肿瘤（MCN）的诊断与治疗。方法 对我院2008年1月至2014年12月49例经术后病理证实为MCN的患者临床资料进行回顾性分析。结果 49例MCN患者中,伴异型性增生39例,伴浸润性癌10例。伴异型性增生的MCN患者中女30例,男9例,平均年龄（46.2±12.7）岁,肿瘤位于胰头部12例,胰体部及胰体尾部18例,胰腺尾部9例;肿瘤平均直径（5.3±3.3）cm。伴浸润性癌的MCN患者中女8例,男2例,平均年龄（51.3±14.7）岁;肿瘤位于胰头部4例,位于胰体尾6例;肿瘤平均直径（7.8±1.8）cm。 所有MCN患者均行手术治疗,结合术后病理切缘情况,47例得到根治性切除,2例切缘为阳性（均伴有浸润性）。肿瘤直径、CA19-9升高、肿瘤内乳头状结构在伴有浸润性癌和伴有异型性增生的MCN患者中具有统计学差异（P＜0.05）。49例均获得随访,随访时间为5～85个月,中位随访时间46.3个月。伴有异型性增生的MCN患者中未见肿瘤复发或转移;伴有浸润性癌的MCN患者中死亡3例,余患者未见肿瘤复发或转移。结论 术前影像学检查对于MCN的诊断有着重要的意义。MCN手术切除后,预后较好,但对于伴有浸润性癌的MCN患者,即使行根治性切除,术后仍需密切随访。     

腹膜假黏液瘤50例报告并文献复习

目的探讨细胞减灭术（CＲS）加腹腔热灌注化疗（HIPEC）在治疗腹膜假黏液瘤（PMP）中临床价值。 方法回顾性分析2017年3月至2018年3月50例腹膜假黏液瘤行CRS+HIPEC的患者病例资料并查阅国内外相关文献。 结果50例患者中,初诊20例,复发30例;行腹腔镜下CRS+HIPEC 7例,开腹下CRS+HIPEC 43例;低级别PMP 41例,高级别PMP 9例。术前肿瘤标志物升高33例,正常17例;联合2脏器切除18例,3脏器切除21例,4脏器以上切除27例,常见联合切除脏器依次为结肠、小肠、脾脏、胃、胆囊;术后出现胸腔积液11例、吻合口漏2例、肠梗阻7例、腹腔脓肿3例、腹腔出血1例、泌尿系瘘1例、切口感染4例、下肢静脉栓塞6例,死亡1例;出血量50~10000 ml,平均696 ml;手术时间4~15 h,平均7.8 h;住院时间5~21 d,平均12.4 d。术后随访时间1年,出现复发13例,死亡1例。 结论CRS+HIPEC作为PMP的标准诊疗技术,亟需临床推广,以改善目前国内PMP治疗现状。     

阑尾源性腹膜假黏液瘤的治疗

目的 探讨阑尾源性腹膜假黏液瘤的治疗效果.方法 回顾性分析1970年至2010年卫生部北京医院收治的51例阑尾源性腹膜假黏液瘤患者的临床资料,对患者手术及复发再手术情况,辅助治疗及随访情况进行分析.术后是否接受腹腔化疗的患者复发再手术间隔时间的比较采用双尾t检验.结果51例患者中48例接受手术治疗,手术时间(135±72) min.34例患者肿瘤复发,其中16例接受再减瘤手术,再手术次数33次.45例患者中位随访时间49.7个月(3～ 132个月),25例带瘤生存,16例无瘤生存,4例死亡.术后病理检查良性型-弥漫性腹膜腺黏液病19例,中间型6例,恶性型-腹膜黏液癌病26例.3、5、10年生存率分别为75％(38/51)、55％(28/51)和22％(11/51).术后接受化疗患者的生存时间和再手术间隔时间分别为(21±4)个月和(10±6)个月,较未接受化疗患者的(19±7)个月和(7±4)个月有所延长,但差异无统计学意义(t=1.027,0.361,P＞0.05).良性型-弥漫性腹膜腺黏液病、中间型及恶性型-腹膜黏液癌病患者中位生存时间分别为96、63、23个月.良性型-弥漫性腹膜腺黏液病患者与恶性型-腹膜黏液癌病患者肿瘤复发间隔时间分别为(15±5)个月和(7±4)个月,两者比较,差异有统计学意义(=2.193,P＜0.05).结论 应该以积极态度实施阑尾源性腹膜假黏液瘤减瘤手术,复发患者合理适时选择二次或多次的减瘤手术,可以延长复发时间,改善患者的预后.     

胰腺非浸润性导管内乳头状黏液肿瘤21例的临床分析

目的探讨非浸润性胰腺导管内乳头状黏液肿瘤的临床特征、治疗及预后。方法收集1999年1月—2005年12月中山医院手术切除的21例非浸润性胰腺导管内乳头状黏液肿瘤患者病历资料并对其进行随访,分析肿瘤的临床特征及手术治疗效果。结果21例非浸润性导管内乳头状黏液肿瘤中,男性17例,女性4例;12例为腺瘤,4例为交界性肿瘤,5例为原位癌;19例位于胰头,2例位于胰体尾;临床表现均以腹痛为主（11/21）,黄疸少见（3/21）,部分无症状（4/21）; CA19-9水平多正常（17/20）或仅轻度升高（3/20）,CT主要表现为囊性占位,其中5例可见病灶与主胰管相通。19例行胰十二指肠切除,2例行胰体尾切除,无手术死亡;术后20例患者得到随访,平均随访时间24个月,至随访结束,除1例失访,1例死于心肌梗塞外,其他患者均存活且未见肿瘤复发。结论非浸润性导管内乳头状黏液肿瘤手术治疗效果极佳,在其尚未恶变前予以切除能改善患者生存;对术后复发的评估可能需要长期的跟踪随访。     

后肾腺瘤诊治1例报告

后肾腺瘤（metanephric adenoma,MA）是一种罕见的肾脏原发上皮源性肿瘤。该肿瘤起源至今仍不清楚,目前WHO（2004）将MA、后肾腺纤维瘤及后肾间质瘤归为一类,统称为后肾肿瘤。北京友谊医院2009年5月收治1例MA,并成功行腹腔镜肾脏部分切除术,现报告如下。     

肠重复来源低级别黏液性肿瘤继发腹膜假黏液瘤1例报告

<正>消化道重复(alimentary tract duplication,ATD)是较少见的先天性畸形,常于婴幼儿期发病,极少有恶变倾向[1]。腹膜假黏液瘤(pseudomyxoma peritonei,PMP)同样是罕见疾病,通常为起源于阑尾的黏液性肿瘤。国外有肠重复来源腹膜假黏液瘤的个案报告[2,3]。2015年我院诊治一例肠重复来源低级别黏液性肿瘤继发腹膜假黏液瘤,现结合文献报道如下。     

经腹入路腹腔镜腹膜后肿瘤切除术安全性初探

目的 探讨经腹入路腹腔镜腹膜后肿瘤（RPT）手术治疗的安全性和有效性。方法 回顾性分析2016年10月至2022年1月收治于内蒙古医科大学附属医院及呼和浩特市第一医院,由同一手术组完成的11例经腹入路腹腔镜腹膜后肿瘤切除术患者临床资料。结果 11例患者均成功实施经腹入路腹腔镜下腹膜后肿瘤切除术,无中转开腹,无围手术期死亡。平均手术时间（202±78）min;中位术中出血量100 mL(20,100)mL;平均术后住院时间（6.9±2.4）d。术后病理：纤维瘤3例,淋巴管囊肿2例,淋巴结增生（Castleman）1例,良性间皮瘤1例,淋巴结核1例,黏液性囊腺瘤1例,高级别脂肪肉瘤1例和平滑肌肉瘤1例。随访4～60个月,除脂肪肉瘤复发外,余无复发。结论 病例选择合适,由腹腔镜经验丰富医师主刀,经腹入路实施腹腔镜腹膜后肿瘤切除术安全且疗效显著,尤其在术中操作及术后恢复方面优势明显。     

腹膜假性黏液瘤的影像研究

腹膜假性黏液瘤（pseudomyxoma peritonei，PMP）是一种以黏液外分泌性细胞在腹膜或网膜种植而导致腹腔内大量胶冻状黏液腹水为特征的疾病，发病率较低，据统计每一万次腹部手术中可有2例。自1884年werth和1901年Frankel先后报道1例来源于阑尾囊腺瘤与阑尾囊肿的PMP以来，关于PMP的报道逐年增多。我们对2001年至2006年间经病理证实的29例PMP的影像表现资料进行分析，现报告如下。     

Appendiceal mucinous neoplasms: a clinicopathologic analysis of 107 cases

The classification of appendiceal mucinous tumors is controversial and terminology used for them inconsistent, particularly when they lack overtly malignant features but are associated with extra-appendiceal spread. We reviewed 107 appendiceal mucinous neoplasms and classified them as low-grade appendiceal mucinous neoplasm (LAMN) (n = 88), mucinous adenocarcinomas (MACAs) (n = 16), or discordant (n = 3) based on architectural and cytologic features. LAMNs were characterized by a villous or flat proliferation of mucinous epithelium with low-grade atypia. Thirty-nine tumors were confined to the appendix, but 49 had extra-appendiceal tumor spread, including 39 with peritoneal tumor characterized by mucin pools harboring low-grade mucinous epithelium, usually dissecting in a hyalinized stroma. Eight of the 16 MACAs lacked destructive invasion of the appendiceal wall and eight showed an infiltrative pattern of invasion. Extra-appendiceal tumor spread was present in 12 MACAs (four peritoneum, seven peritoneum and ovaries; one ovaries only). In MACAs with an infiltrative pattern, peritoneal tumor consisted of glands and single cells in a desmoplastic stroma. The peritoneal tumor in the remaining cases consisted of mucin pools that contained mucinous epithelium with high-grade atypia and, in some cases, increased cellularity compared with that seen in peritoneal spread in cases of LAMN. Three cases were classified as discordant because the appendiceal tumors were LAMNs but the peritoneal tumors were high-grade. Follow-up was available for 49 LAMNs, 15 MACAs, and 2 discordant cases. None of the patients with LAMNs confined to the appendix experienced recurrence (median follow-up 6 years). LAMNs with extra-appendiceal spread were associated with 3-, 5-, and 10-year survival rates of 100%, 86%, and 45%, respectively. Patients with MACA had 3- and 5-year survival rates of 90% and 44%, respectively (p = 0.04). The bulk of peritoneal disease correlated with prognosis among patients with MACA (p = 0.04) and, to a lesser degree, among patients with LAMNs (p = 0.07). We conclude that: 1) appendiceal mucinous neoplasms can be classified as either low-grade mucinous neoplasms or mucinous adenocarcinoma based on architectural and cytologic features; 2) tumors that can be confidently placed in the low-grade group (which requires rigorous pathologic evaluation of the appendix) and are confined to the appendix are clinically benign in our experience to date; 3) low-grade tumors confined to the appendix are morphologically identical to those with extra-appendiceal spread (except for the usual identification of breach of the wall in the latter cases) and the same designation is appropriate for the appendiceal neoplasia in each situation; 4) the long-term outlook for patients with low-grade tumors and peritoneal spread is guarded with just over half dying of disease after 10 years; 5) appendiceal mucinous tumors with destructive invasion of the appendiceal wall, complex epithelial proliferations, or high-grade nuclear atypia generally pursue an aggressive clinical course and should be classified as mucinous adenocarcinomas; 6) peritoneal tumor can be classified as involvement by LAMN or MACA, and this distinction is of prognostic significance; 7) bulky peritoneal tumor worsens prognosis; and 8) LAMNs associated with high-grade peritoneal tumor behave as adenocarcinoma.     

Mucinous Neoplasms of the Vermiform Appendix

Most epithelial neoplasms of the vermiform appendix are of mucinous type and can be stratified into 3 main diagnostic categories: (1) adenoma, (2) mucinous neoplasms of uncertain malignant potential or low-grade mucinous neoplasm, and (3) adenocarcinoma. Clinically, appendiceal mucinous adenomas and adenocarcinomas may present as right lower abdominal pain mimicking acute appendicitis, a mass, or pseudomyxoma peritonei. Nomenclature currently in use to describe and diagnose mucinous tumors of the appendix, particularly those of low morphologic grade, varies among surgical pathologists and centers, resulting in different histologic and clinical features being attributed to these entities in the literature. It may be of help, as already attempted by some investigators, to simply apply algorithmic parameters for such lesions (grade of the primary lesion, extensiveness and composite of extra-appendiceal involvement, and so forth), instead of adopting rigid classification categories. This approach allows for more objective data to be collected in hopes that it will provide a more nuanced understanding of the clinical behavior of the spectrum of mucinous appendiceal tumors. Remaining focused on histopathologic parameters of the primary and secondary sites of involvement may help in avoiding circular reasoning.     

Appendicular mucocele: two case reports and literature review

The classification of mucinous tumors of the vermiform appendix is quite controversial, and includes a spectrum of neoplastic lesions ranging from benign proliferations, intraluminal, to invasive adenocarcinomas. Among the complications of appendicular mucinous neoplasms we should mention the “pseudomyxoma peritonei”, a condition caused by cancerous cells (mucinous adenocarcinoma) that produce abundant mucin or gelationous ascites. Mucinous neoplasms of the appendix are rare diseases of unknown etiology. The diagnosis is difficult because of poorly specific clinical, biochemical and imaging parameters, and their detection can be occasional. Most of the reported cases involving women of reproductive age (with a history of endometriosis, abdominal surgery or pelvic inflammatory disease). The definitive diagnosis requires histology and immunohistochemistry. Cytoredutive surgery combined with hyperthermic intraperitoneal chemoterapy (HIPEC) is now considered the best treatment for this disease.We present two cases treated with surgery and HIPEC.     

Pseudomyxoma peritonei associated with mucinous cystadenoma of the appendix

The authors report a case of a male 86 years old patient with peritoneal pseudomyxoma associated to cystoadenoma of the appendix. Preoperative CT scan showed the presence of a mass in the appendiceal site containing a gelatinous fluid collection and calcifications. Notwithstanding, diagnosis of pseudomyxoma was preoperatively considered less probable due to the rarity of the affection and the advanced age. At laparatomy was revealed the presence of the large mass observed at CT scan, involving the caecum and occupying the retroperitoneal space along the ascending colon. Mucinous ascites was present without invasive mucinous implants in the peritoneum. Operation consisted in a right hemicolectomy with total removal of the retroperitoneal mass and evacuation of the mucinous ascites. Histology confirmed the clinical diagnosis of pseudomyxoma peritonei associated to cystoadenoma of the appendix. The case is of paradigmatic interest as being quite correspondent to the classical Ronnett's definition of pseudomyxoma: a clinicopathological entity characterized by mucinous ascites and non-invasive mucinous implants with a characteristic distribution and containing histologically benign mucinous epithelium derived from an appendiceal mucinous adenoma and having a benign course. According to such definition, the authors stress the importance of an appropriate classification of the observed cases of pseudomyxoma, under whose term is often collected a heterogeneous group of pathological lesions, in order to better evaluate the prognosis and treatment.     

Prognostic significance of localized extra-appendiceal mucin deposition in appendiceal mucinous neoplasms

Appendiceal mucinous neoplasms confined to the mucosa are benign, whereas those with disseminated peritoneal mucin deposits often follow an indolent, but malignant, course. Not infrequently, appendiceal mucinous neoplasms are associated with localized periappendiceal mucin deposits, but lack diffuse peritoneal involvement. Mucin deposits in these cases may be acellular or contain neoplastic epithelium (cellular mucin). Although some investigators consider both acellular and cellular periappendiceal mucin to pose no, or minimal, risk for recurrent disease, the biologic importance of localized extra-appendiceal mucin has never been evaluated. We identified 65 patients with appendiceal mucinous neoplasms, all of whom had localized periappendiceal mucin deposits without diffuse peritoneal involvement, and assessed them for the presence of extra-appendiceal epithelium and clinical outcome. Forty-nine (75%) appendices were submitted in total for histologic evaluation. Most (77%) cases showed acellular periappendiceal mucin, but 15 (23%) had scant extra-appendiceal epithelium (range: 1 to 12 cell clusters). Upon follow-up (mean: 48 mo), 2 (4%) patients with acellular periappendiceal mucin developed diffuse peritoneal disease, but neither of these appendices was submitted in total for histologic evaluation. In contrast, 5 of 15 (33%) patients with cellular periappendiceal mucin developed mucinous ascites, including 1 who eventually died of disease (P=0.03). Thus, patients with appendiceal mucinous neoplasms and acellular periappendiceal mucin are unlikely to develop recurrent disease. However, microscopic examination of the entire appendix is necessary, as lesions with extra-appendiceal tumor cells are more likely to progress to disseminated disease and result in death of the patient, even if the mucin is paucicellular and confined to the periappendiceal region.     

Emergency laparoscopic ileocecal resection for a low-grade appendiceal mucinous neoplasm with impending rupture: A case report

Introduction and importanceWe report the case of a patient with a low-grade appendiceal mucinous neoplasm (LAMN) who underwent emergency laparoscopic ileocecal resection to avoid the metastatic spread of tumor cells due to an impending rupture.Case presentationA 55-year-old woman presented to our hospital with pain in the right lower quadrant of the abdomen. Computed tomography revealed a markedly tense appendiceal mucinous tumor with surrounding inflammation, and laboratory test results showed elevated serum C-reactive protein (7.47 mg/dL), indicating impending rupture of the appendix. Magnetic resonance imaging revealed nodules inside the appendix, suggesting the possibility of appendiceal cancer. We performed emergency laparoscopic ileocecal resection with regional lymph node dissection. The tumor was pathologically diagnosed as a LAMN without rupture.Clinical discussionLAMN is classified as a clinically malignant tumor because it can cause pseudomyxoma peritonei due to perforation or the presence of residual tissue. Although an appendectomy would be appropriate for LAMN if the tumor margin is secured, ileocecal resection with lymph node dissection is necessary when preoperative discrimination of appendiceal cancer is impossible.ConclusionFurther studies of preoperative imaging for appropriate differential diagnosis were necessary.     

Ovarian mature teratomas with mucinous epithelial neoplasms: morphologic heterogeneity and association with pseudomyxoma peritonei

Mucinous epithelial neoplasms arising in association with mature teratomas are a heterogeneous group of tumors, but with the exception of a single recent study, their full histologic spectrum, detailed immunophenotype, and association with classic pseudomyxoma peritonei (PMP) have not been fully studied. The morphologic, immunohistochemical, and clinical features of 42 patients with mucinous epithelial tumors arising in association with mature ovarian teratomas were evaluated. The patients' ages ranged from 17 to 66 years (mean, 39 y). Tumor size ranged from 5.5 to greater than 200 cm. Most teratoma-associated mucinous tumors were unilateral, although 1 patient harbored bilateral mucinous tumors in association with bilateral teratomas. In all cases, the teratomatous component consisted of mature elements. Using the 2003 World Health Organization criteria for ovarian intestinal type mucinous neoplasms, 17 (40%) were classified as mucinous cystadenoma, 16 (38%) as intestinal-type mucinous epithelial neoplasm of low malignant potential (IM-LMP), 4 (10%) as intraepithelial carcinoma (IEC), and 5 (12%) as invasive mucinous carcinoma. Mucinous cystadenomas had a varied epithelial lining consisting of lower gastroenteric, gastric foveolar, or müllerian appearance. In contrast, the IM-LMP, IEC, and invasive carcinoma cases had a more uniform lower gastroenteric histology. For mucinous cystadenomas, a cytokeratin (CK) 7+/CK20- phenotype (5/13; 38%) was equally as common as a CK7-/CK20+ phenotype (5/13; 38%), with the remaining cases coexpressing both keratins (CK7+/CK20+: 3/13; 23%). In contrast, IM-LMP, IEC, and invasive adenocarcinomas more frequently had a CK7-/CK20+ phenotype (56%, 50%, and 100%, respectively). A CK7+/CK20-phenotype was rare in these later 3 morphologic groups (6%). Of the 42 total cases, 55% had pseudomyxoma ovarii and 24% had classic PMP (1 cystadenoma, 6 IM-LMP, and 3 invasive carcinomas), whereas 5% had more localized accumulations of peritoneal mucin (both IM-LMP). Pathologic evaluation of the peritoneum in these 12 cases revealed 6 with acellular mucin alone, 3 with low-grade mucinous epithelium (all 3 with ovarian IM-LMP), and 3 with high-grade mucinous carcinomatosis (all 3 with ovarian mucinous adenocarcinoma). No appendiceal lesions were identified. Follow-up was available in 48% of patients (mean, 61 mo). The only adverse outcomes occurred in the 3 patients with ovarian carcinoma and associated peritoneal carcinomatosis. We report that a significant proportion of mucinous tumors associated with mature ovarian teratomas present with clinical PMP, which in most cases is associated with IM-LMP. PMP in this setting may harbor microscopic intra-abdominal low-grade mucinous epithelium that is histologically and immunophenotypically similar to that typically seen in appendiceal-related PMP. Pseudomyxoma ovarii is common in this setting, particularly in tumors with IM-LMP histology, but pseudomyxoma ovarii is not predictive of PMP. Ovarian teratoma-associated benign and IM-LMP mucinous neoplasms with microscopic peritoneal low-grade mucinous epithelium do not seem to be at significant risk for intra-abdominal recurrence, but numbers are few and follow-up is limited. In contrast, teratomas with an invasive carcinomatous component and microscopic peritoneal carcinomatosis follow an aggressive clinical course.     

Clinical Surveillance After Macroscopically Complete Surgery for Low-Grade Appendiceal Mucinous Neoplasms (LAMN) with or Without Limited Peritoneal Spread: Long-Term Results in a Prospective Series

Background

Low-grade appendiceal mucinous neoplasm (LAMN) is the most common primary lesion of pseudomyxoma peritonei, a disease whose standard treatment is cytoreduction and hyperthermic intraperitoneal chemotherapy. The optimal management of LAMN is not well defined. This study prospectively assessed a clinical surveillance strategy for LAMN with or without limited peritoneal spread.

Methods

During 2003–2017, the study prospectively enrolled 41 patients treated by macroscopically complete surgery for LAMN with or without limited peritoneal spread (pelvis and right lower quadrant). Follow-up assessment included thoracic-abdomino-pelvic computed tomography scan and serum tumor markers scheduled after surgery, then every 6 months for 5 years, and yearly thereafter. All specimens were reviewed by a dedicated pathologist.

Results

Appendectomy and five right colectomies were performed for 36 patients. Nine patients also underwent macroscopically complete cytoreduction of mucinous peritoneal disease, and four patients had hysterectomy plus bilateral salphingo-oophorectomy. Appendiceal rupture was evaluable in 38 of the 41 patients, being present in 21 patients (51.2%). Mucin, cells, or both outside the appendix were observed in 24 patients (58.5%). The median follow-up period was 58 months (range 9.3–162 months). The 5-year recurrence-free survival rate was 95.1%. Only two patients experienced peritoneal recurrences (4.9%), respectively 18 and 22 months after appendectomy. Their primary lesions were LAMNs with and without appendix wall rupture or extra-appendiceal mucin, respectively. No death occurred.

Conclusion

These findings strongly suggest that radically resected LAMN, even with limited peritoneal spread, carries a low recurrence risk. Furthermore, appendix wall perforation and the presence of mucin, cells, or both outside the appendix were not associated with a higher risk of metachronous peritoneal dissemination. In this setting, clinical and radiologic surveillance is a viable choice.

     

The mucin profile of noninvasive and invasive mucinous cystic neoplasms of the pancreas

Recently, it was shown that ductal adenocarcinomas and intraductal papillary-mucinous neoplasms of the pancreas differ in their expression of the mucin markers MUC1 and MUC2 while both tumors express MUC5AC. It is not known whether mucinous cystic neoplasms of the pancreas have their own mucin profile. To clarify this issue, 22 mucinous cystic neoplasms were examined immunohistologically for their expression of MUC1, MUC2, MUC5AC, and MUC6 and also for the protein products of the tumor suppressor genes p53 and DPC4 and the mismatch repair genes. Noninvasive mucinous cystic neoplasms, regardless of the degree of cellular atypia, were all positive for MUC5AC and negative for MUC1, with the exception of the cyst-lining epithelium of a single case with eosinophilic cytology (case no. 16). Only in cases with an invasive component was MUC1 expression observed. MUC2 expression was restricted to goblet cells scattered within the epithelium of the mucinous cystic neoplasms and was often accompanied by endocrine cells, a further indication of intestinal differentiation. DPC4 expression was maintained in all tumors, except for three invasive carcinomas. p53 nuclear reactivity was found in one borderline tumor and four invasive mucinous cystic carcinomas. The results suggest that the epithelium of noninvasive mucinous cystic neoplasms does not differ in its expression of MUC5AC from ductal adenocarcinomas, intraductal papillary-mucinous neoplasms, and metaplastic pancreatic duct epithelium. The fact that noninvasive mucinous cystic neoplasms lack MUC1 expression (except for an eosinophilic variant) but express it when they become invasive might be used as a marker indicating the step of progression from noninvasiveness to invasiveness.