Diverticular disease of the vermiform appendix: a diagnostic clue to underlying appendiceal neoplasm

The Significance of Appendiceal Diverticulosis to the Emergency General Surgeon: A Case Report and Literature Review

Acute appendicitis is a common acute general surgical presentation; however, variants in the appendicular anatomy and the presence of cancers can complicate the surgical management of this condition. Appendiceal diverticula (AD) are rare pathological outpouchings along the appendix body. These outpouchings complicate and obscure the surgical planes, making adequate surgical resection of the appendix difficult. We report here the surgical management of a rare case of AD with a benign neuroma that highlights the importance of adequate pre-operative planning and variations in the standard anatomy. Through the literature review, the association of AD with cancers arising from the appendix is also presented.

Episodic Abdominal Pain-An Unexpected Cause for a Common Clinical Problem

A previously healthy 55-year-old male patient presented repeatedly to the emergency department with severe episodic periumbilical abdominal pain. After an extensive diagnostic work-up and subsequent clinical deterioration, appendiceal diverticulitis was diagnosed. We identified a correlation of white blood cell counts and possibly faecal calprotectin with the clinical presentation. We suggest that appendiceal diverticulitis should be considered in middle-aged patients with recurrent episodes of abdominal pain that correlate with laboratory markers of inflammation.

Clinical features and risk factors for appendiceal diverticulitis: a comparative study with acute appendicitis

PURPOSE

Despite their similar clinical characteristics, appendiceal diverticulitis (AD) and acute appendicitis (AA) are pathologically distinct. This study compared the clinical features of AD and AA and identified relevant risk factors.

METHODS

Patients who underwent appendectomy with a preoperative diagnosis of either AD or AA were categorized based on histopathological findings. The two groups were compared in terms of various clinical factors.

RESULTS

Among the 854 patients included in the study, a histopathological evaluation revealed 49 and 805 cases of AD and AA, respectively. A univariate analysis demonstrated that AD was more prevalent than AA among older, taller, and heavier males. A multivariate analysis revealed that male sex, a white blood cell (WBC) count < 13.5 × 103/μL, an eosinophil count ≥ 0.4%, and a mean corpuscular volume (MCV) ≥ 91.6 fL were significant factors differentiating AD from AA. In addition, pathological AD emerged as an independent risk factor for abscess and/or perforation.

CONCLUSIONS

AD was associated with an older age, robust physique, and significant risk of abscess and/or perforation despite a low WBC count. In addition to imaging modalities, the preoperative factors of male sex, a WBC count < 13.5 × 103/μL, an eosinophil count ≥ 0.4%, and a MCV ≥ 91.6 fL may be useful for distinguishing AD from AA.

A unique case of appendiceal diverticulum presenting with positive faecal immunochemical test

Appendiceal diverticulum is a rare condition that usually presents with symptoms similar to acute appendicitis. Although imaging can be used to aid the diagnosis of this condition, it is usually confirmed postoperatively on the basis of histology. Because of an increased risk of appendiceal neoplasms, the usual management is prophylactic appendicectomy. We report the case of a 70-year-old lady with no symptoms referred from her GP surgery for a positive faecal immunochemical test as part of the bowel screening programme. Colonoscopy showed a mass at the appendiceal orifice with normal histology. She underwent an appendicectomy with a small cuff of caecal resection. The lesion was ~8 cm at its maximum dimension and showed appendiceal diverticulum. Appendiceal diverticulum is an important differential diagnosis to consider in patients with atypical history of acute appendicitis or positive faecal immunochemical test with no other symptoms.

Is Appendiceal Diverticulitis Mimicking Acute Appendicitis?

Appendicular diverticulitis (AD) is a rare entity characterized by the inflammation of the arising diverticulum of the appendix. It has been reported to carry a high risk of perioperative complications, such as bleeding and perforation. Furthermore, multiple articles have highlighted the importance of diagnosing AD early due to its strong association with malignancies. Limited published cases concerning AD in our country and globally are available in the literature. Hence, we present in this article a case series of five exciting cases of incidental findings of AD that were initially diagnosed as acute appendicitis based on clinical evaluation and imaging findings. In our series, we performed a retrograde evaluation of the computed tomography scans of all five cases that showed diverticula. In conclusion, histopathological evaluation remains the method of choice to reach the definitive diagnosis; however, it is essential to highlight the relevance of imaging in diagnosing AD preoperatively in the early stages to reduce morbidity and mortality.

Complicated appendiceal diverticulitis a extremely rare cause of acute abdomen: A case report and literature review

INTRODUCTION AND IMPORTANCE

Appendiceal diverticulitis (AD) represents a rare cause of acute abdomen. Diagnosis of AD is a challenge because of its rarity and resemblance to other ileocecal diseases like as cecal diverticulitis (CD) and acute appendicitis (AA). Preoperative imaging can be useful to aid diagnosis. Surgery represents the correct treatment of AD.

CASE PRESENTATION

A 48-year-old Caucasian male presented to the Emergency Department with a two-day history of right lower quadrant (RLQ) abdominal pain and fever. Physical examination revealed RLQ abdominal pain and rebound tenderness with muscle guarding. Laboratory tests reported high levels of C-reactive protein and neutrophilic leukocytosis. Abdominal computed tomography(CT) scan showed findings of AA and a thin-walled 5 mm appendiceal diverticulum. The patient underwent laparoscopic appendectomy. The postoperative course was uneventful, the patient was discharged on the 5th postoperative day in a stable condition. Gross anatomy confirmed the presence of appendiceal diverticulum in the distal appendix on the mesenteric border. Histopathological examination revealed an inflamed and perforated appendiceal pseudo-diverticulum with surrounding AA and peri-appendicitis.

CLINICAL DISCUSSION

Appendiceal diverticulosis is an uncommon entity, classified as congenital or acquired based on the number of appendiceal layers herniating through the normal wall. Two thirds of diverticula will develop acute or chronic diverticulitis that can lead to several complications some of which can be life-threatening.

CONCLUSION

AD is a rare surgical emergency and represents often an overlooked diagnosis. Early diagnosis and treatment are crucial for reducing morbidity and mortality Appendectomy represents a safe and appropriate treatment of AD.

A rare case of ruptured appendiceal diverticulitis: A significant surgical pathology

Appendiceal diverticulitis is a rare pathology which is distinctly different to acute appendicitis and associated with higher rates of morbidity and mortality. Furthermore, diagnosis is often retrospective on histopathological analysis of appendicectomy specimens due to the atypical clinical and radiological features. Herein, we present a case of ruptured appendiceal diverticulitis in a young patient with atypical clinical features and a radiologically normal appearing appendix in close proximity to an inflammatory phlegmon. This case highlights the importance of maintaining a high clinical suspicion of surgical pathology and considering atypical diagnosis in patients with inflammatory changes in the right iliac fossa.

Appendiceal diverticulitis and inflammatory bowel disease

Appendiceal diverticulitis is known as a rare pathology and its etiology remains largely unknown. We describe a case of a 41-year-old woman with a past history of inflammatory bowel disease (IBD) who was admitted to the Emergency Department at a rural hospital in Australia with right iliac fossa pain (RIF) and later was found to have acute appendiceal diverticulitis on histopathologic studies. Thus far, no literature has described IBD as one of the possible contributing factors of appendiceal diverticulitis. This paper aims to shed light on the possible causative relation between appendiceal diverticulitis and IBD.

Appendiceal Diverticulitis Presenting as Acute Appendicitis: A Case Report

Appendiceal diverticulitis (AD) is an overlooked pathology that carries a high risk of perforation and associated neoplasia, especially carcinoid tumours and mucinous adenoma. AD may be congenital, but more commonly acquired. It may cause diverticulitis, which causes clinical and radiological signs like those of acute appendicitis, and that may delay the diagnosis till it is confirmed on histopathological examination. Here we report a case of acute AD in a case initially diagnosed as acute appendicitis.

Diverticulitis and Diverticulosis of the Appendix: A Case Series

Introduction Diverticula of the appendix is a rare entity, may be complicated by inflammation/infection, and clinically mimics acute appendicitis. The reported associated risk factors include male gender, Hirschprung's disease, cystic fibrosis and adult age, where some reports claim that they are also associated with an increased risk of appendiceal malignancy. Imaging has a place in pre-operative diagnosis, however, most of the cases were diagnosed during a pathological examination after surgery. They are associated with a higher rate of perforation (more than four times compared with classical acute appendicitis). In this review, we present a case series of five patients diagnosed with diverticulitis and one with diverticulosis of the appendix that were managed at a single centre. Our aim is to explore the common clinical, radiological, and intra-operative findings associated with this disease as well as the outcome of management. Materials and methods A total number of six cases of diverticular disease of the appendix diagnosed and managed at Basildon University hospital in the period between 2016 and 2020 were studied. The demographic details and clinical data including presenting symptoms, laboratory results, radiological characteristics, intraoperative findings and histopathological features were analysed. Results The study group included four males and two females, with an age range of 20-84 years. The most common presenting clinical symptoms were right iliac fossa abdominal pain, nausea, anorexia, and diarrhoea. Half of the cases showed a thickened appendix in the pre-operative CT scan. An inflamed or perforated appendix was seen in five cases as well as inflammation of the diverticula. Conclusion Appendiceal diverticulitis is an uncommon pathology that imitates acute appendicitis, and appendicectomy is the standard treatment. Prophylactic appendicectomy is recommended for non-inflamed diverticula - this is due to the potential risk of inflammation, perforation, and the risk of developing an appendiceal neoplasm.

Complicated appendicular diverticulitis

Appendiceal diverticulitis, a frequently underdiagnosed entity, differs from typical appendicitis by the presence of an inflamed appendiceal diverticulum. Appendiceal diverticulitis is a surgical emergency which has an increased risk of perforation compared to typical appendicitis. We will discuss a surgically and pathologically confirmed case of complicated appendiceal diverticulitis and its management implications.

A rare triad of appendiceal diverticula, appendiceal carcinoid, and colonic diverticula

Appendiceal diverticulosis is a rare finding associated with appendiceal neoplasms. Both can masquerade as appendicitis in patients and are overlooked in differentials of right upper quadrant pain. A 37-year-old African American female presented with appendicitis-like symptoms to the emergency room with fever and leukocytosis. Appendectomy was performed with pathological evaluation revealing coexisting appendiceal diverticula and carcinoid of the appendix with lymphovascular invasion and mesoappendiceal involvement. In line with the National Comprehensive Cancer Network guidelines, right hemicolectomy with lymph node dissection was performed which was negative for neoplastic invasion but positive for colonic diverticulosis. While there have been many case reports of appendiceal diverticula with coexisting appendiceal carcinoid, a concurrent colonic diverticulum in the right hemicolectomy specimen during the oncologic resection of the appendiceal carcinoid has not been previously reported. We propose colonic diverticula as another possible feature that may be associated with appendiceal diverticula especially with an underlying appendiceal neoplasm.

Appendiceal diverticulum masquerading as acute appendicitis

Appendiceal diverticula present as rare clinical finding and are most confused with acute appendicitis. A 65-year-old female was presented to our surgical service after 1 day of right lower quadrant abdominal pain and a computed tomography evaluation, read as a diagnosis of acute appendicitis. Due to the location and quality of pain and intraoperative findings acute appendicitis was our preliminary diagnosis. Follow up with histopathology confirmed acute inflammation of an appendiceal diverticulum. With discordance in original diagnosis from final pathological evaluation, we suggest appendiceal diverticula as an important differential to consider in patients of similar clinical presentation. Surgical treatment with appendectomy and final histological diagnosis are essential in the proper treatment of this rare clinical finding.

A rare simultaneous occurrence of appendiceal diverticulitis and non‐perforated peptic ulcer mimicking abdominal peritonitis symptoms

Appendiceal diverticulitis is an infrequent disease that can mimic other diseases’ symptoms or cause different symptoms because of its various complications. However, one of the most frequent complications of this disease is a perforation that can lead to other serious problems such as peritonitis. This complication can threaten a patient's health condition. In this article, a male patient presented with abdominal pain and was admitted to the surgical ward with suspicion of a perforated peptic ulcer. However, more investigation showed a simultaneous occurrence of peptic ulcer and perforated appendiceal diverticulitis that cause peritonitis symptoms.

Appendiceal Diverticulitis Presenting as Acute Appendicitis and Diagnosed After Appendectomy

Introduction

Diverticular disease of the appendix (DDA) is a rare appendiceal pathology. It is usually present similar to acute appendicitis. Because of its rarity, the DDA is poorly comprehended. This study evaluates the incidence, clinical and pathological characteristics of appendiceal diverticulitis diagnosed after appendectomy.

Methods

We performed a retrospective analysis of patients who underwent appendectomy between January 2016 and January 2022 at the Istanbul Sultanbeyli State Hospital General Surgery Clinic. The following parameters were analyzed: age and gender, preoperative diagnosis, laboratory results, radiological imaging findings, surgical technique, histopathological examination of specimens, and complications.

Results

A total of 1586 patients were analyzed. In the pathology, diverticular disease of the appendix was detected in 10 patients (0.63%). The DDA patients’ mean age was 34.4 years, and the male to female ratio was 4:1. We detected low-grade appendiceal mucinous neoplasia in one of our patients.

Conclusion

Appendiceal diverticulitis is rare and usually presents as acute appendicitis. Most DDAs are detected incidentally during the postoperative period and are associated with an increased risk of appendiceal neoplasm. Appendectomy specimens should be carefully examined histopathologically to detect diverticular disease of the appendix.

A case of Pseudomyxoma Peritonei of an unexpected origin

Background

Pseudomyxoma peritonei (PMP) is a complex and partially understood disease defined by mucin deposits in the peritoneal cavity, mostly of appendiceal origin caused by the rupture of a mucocele often containing Low or High grade Appendiceal Mucinous Neoplasm (LAMN/HAMN). Other origins include primitive ovarian mucinous cystadenoma or cystadenocarcinoma almost always with an associated teratoma, but to our knowledge no case of ovarian teratomatous appendiceal-like mucocele with LAMN has been reported as a cause of PMP.

Case presentation

A 25-year old female with infertility was diagnosed with an isolated left ovarian tumor in a context of PMP. Histological examination revealed an ovarian teratoma containing an appendiceal-like structure with mucocele and LAMN, without any associated lesion of the appendix on full histological analysis. Molecular characterization of the ovarian lesion showed co-KRAS and GNAS mutations, as described in PMP of appendiceal origin, while only KRAS mutations are reported in primitive ovarian mucinous tumor.

Conclusions

Detection of co-KRAS and GNAS mutations in our case of ovarian teratomatous appendiceal-like mucocele with LAMN shows that when PMP derives from a mucinous ovarian lesion (with histological proof of none-appendiceal involvement), it is probably of a digestive teratomatous origin, emphasizing the need to actively search for tetatomatous signs in a context of ovarian PMP.

Coexistence of low-grade mucinous neoplasm and carcinoid (collision tumor) within multiple appendiceal diverticula: A case report

Neoplasms of the appendix are very rare. They usually show glandular or neuroendocrine differentiation, and when they both occur in the same area, it is called a “collision tumor.” Low-grade mucinous neoplasms associated with appendiceal diverticula are also uncommon. The appendectomy specimen of a 60-year-old man contained dense and mucoid luminal content on the distal tip, and similarly a solid, yellow, lumen-obscuring tumor with a diameter of 1.5 cm at the base of the appendix was detected. Microscopically, there were three diverticula that comprised herniation of the mucosal layer through the appendiceal wall. Interestingly, all of the diverticula and the normal-appearing appendiceal wall were lined by adenomatous epithelium. The luminal portion had pools of mucin-containing, rare clusters of low-grade epithelium that gave rise to the diagnosis of a “low-grade mucinous neoplasm.” The solid-appearing tumor was diagnosed as a “neuroendocrine neoplasm,” and there was no transition zone between these two types of tumors. There are some cases that have been reported as low-grade mucinous neoplasms associated with appendicular diverticula and collision tumors consisting both mucinous neoplasms and carcinoid tumors in the literature; our case has a unique appearance with two different types of tumors both in the appendix wall and within multiple diverticula.

Diverticular Disease of the Appendix Is Associated with Complicated Appendicitis

INTRODUCTION

Diverticular disease of the vermiform appendix (DDA) has an incidence of 0.004 to 2.1% in appendicectomy specimens. DDA is variably associated with perforation and malignancy. We report a single-center experience of DDA. The primary aim is to validate the association of DDA with complicated appendicitis or malignancy, and the secondary aim is to validate systemic inflammatory response syndrome (SIRS) criteria and quick Sepsis-related Organ Failure Assessment (qSOFA) scores.

METHODS

The histopathology reports of 2,305 appendicectomy specimens from January 2011 to December 2015 were reviewed. Acute appendicitis was found in 2,164 (93.9%) specimens. Histology of the remaining 141 (6.1%) patients revealed: normal appendix (n = 110), DDA (n = 22), endometriosis of appendix (n = 6), and an absent appendix (n = 3). Patient demographics, clinical profile, operative data, and perioperative outcomes of DDA patients are studied. Modified Alvarado score, Andersson score, SIRS criteria, and qSOFA scores were retrospectively calculated.

RESULTS

The incidence of DDA was 0.95%. Ten patients (45.5%) had diverticulitis. The mean age of DDA patients was 39.5 years (range 23-87), with male preponderance (n = 12, 54.5%). The median Modified Alvarado score was 8 (range 4-9), and the median Andersson score was 5 (range 2-8). Fourteen patients (63.6%) had SIRS, and none had a high qSOFA score. Eight patients (36.4%) had complicated appendicitis (perforation [n = 2] or abscess [n = 6]). Eleven (50%) patients underwent laparoscopic appendicectomy. There were three 30-day readmissions and no mortality.

CONCLUSION

DDA is a distinct clinical pathology associated with complicated appendicitis.

Appendiceal Diverticulitis in a Young Female Diagnosed on Pathology after Laparoscopic Appendectomy for Acute Appendicitis

Background. Appendiceal diverticulitis is a rare cause of inflammation of the appendix, which may mimic acute appendicitis. Its diagnosis is often delayed, and its occurrence carries an increased risk of significant complications, such as perforation. Case Presentation. A 23-year-old woman presented with sudden onset, severe, right lower quadrant abdominal pain and nausea. Her WBC was elevated, and abdominal CT showed findings indicative of acute appendicitis with a 13 mm fluid-filled appendix and local stranding. During laparoscopic appendectomy, significant inflammation was found around the appendix with some mucous material around the tip. The appendix base was not involved, and an endoloop was used to secure the stump. No other intra-abdominal abnormalities were observed. The patient recovered uneventfully. Pathology showed no classic appendicitis but appendiceal diverticulitis with signs of perforation. Discussion. Appendiceal diverticulitis is a rare condition which cannot be distinguished from acute appendicits clinically and on imaging. Diagnosis may be established based on pathology such as in our case. Appendectomy is indicated in appendiceal diverticulitis, and an appendix diverticulum is incidentally found during surgery or other investigations. This is due to the increased risk of perforation and the reported development of malignant tumors, including the appendix carcinoid.

Retrospective case-control study to predict a potential underlying appendiceal tumor in an acute appendicitis context based on a CT-scoring system

OBJECTIVES

To assess CT signs to discriminate an appendiceal tumor versus a non-tumoral appendix in an acute appendicitis context.

METHODS

A 10-year bicentric retrospective case-control study was performed in adults. Patients with a histopathological appendiceal tumor and appendicitis were paired for age and sex with patients with non-tumorous appendicitis (1/3 ratio, respectively). Two senior radiologists blindly analyzed numerous CT findings with final consensus to perform univariate and multivariate statistical analyses. A diagnostic CT scan score was calculated with a bootstrap internal validation. Reproducibility was assessed based on the kappa statistic.

RESULTS

A total of 208 patients (51 +/- 21 years; 114 males) were included (52 patients in the tumor group and 156 in the non-tumor group). In the multivariate analysis, an appendicolith and fat stranding were protective factors with OR = 0.2 (p = 0.01) and OR = 0.3 (p = 0.02), respectively, while mural calcifications (OR = 47, p = 0.0001), an appendix mass (OR = 7.1, p = 0.008), a focal asymmetric wall abnormality (OR = 4.9, p = 0, 001), or a ≥ 15 mm diameter (OR = 3.5, p = 0.009) were positive predictive factors of an underlying tumor. Using a ≥1 cut-off, our diagnostic score had an AUC = 0.87 (95 % CI, 0.82-0.93) and a positive likelihood ratio = 13.5 (95 % CI, 6.7-27.1).

CONCLUSION

We developed a reliable scoring system based on CT findings, which is highly predictive of an underlying appendiceal neoplasm in an appendicitis context using a ≥1 cut-off.

Mucosal prolapse syndrome-like inflammatory polyp protruding from the appendiceal orifice masquerading as an appendiceal neoplasm: A rare case report

We describe a case of a mucosal prolapse syndrome (MPS)-like inflammatory polyp protruding from the appendiceal orifice, mimicking an appendiceal neoplasm. A 48-year-old man presented with lower abdominal pain and elevated white blood cell count and C-reactive protein level. Computed tomography showed a swollen appendix with multiple small saccular lesions and periappendiceal fat stranding and small saccular lesions in the ascending colon and cecum. Ultrasonography showed a swollen appendix 25 mm in diameter with multiple saccular structures and a periappendiceal high-echoic area, suggesting appendiceal diverticulitis. Colonoscopy revealed an erythematous lesion protruding from the appendiceal orifice. An ileocecal resection was performed based on a preoperative diagnosis of appendiceal diverticulitis and tumor. Histopathological examination of the appendix showed multiple mucosal herniations with infiltration of inflammatory cells, indicating appendiceal diverticulitis. The tumor was characterized by glandular duct hyperplasia and stromal expansion with smooth muscle hyperplasia and was diagnosed as an inflammatory polyp resembling an MPS lesion. Although several studies have shown the macroscopic and endoscopic appearance of MPS-like inflammatory lesions associated with colonic diverticular disease, this case was the first to present an inflammatory polyp associated with appendiceal diverticulitis in which the lesion protruding from the appendiceal orifice was masquerading as an appendiceal neoplasm.

Updated staging and patient outcomes in low-grade appendiceal mucinous neoplasms

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.

A case of Type 2 appendiceal diverticulum perforated and a review of the literature

BACKGROUND

Appendiceal diverticulosis disease is a rare entity. An perforated appendiceal diverticulosis mimicking acute appendicitis is a extremely unusual surgical finding and the reported prevalence is between 0.014 and 3.7%.

CASE REPORT

We report the case of an elderly man, who presented with a typical clinical image of acute appendicitis and underwent laparoscopic surgery. Intraoperative an acute appendicitis with localized peritonitis was identified and a laparoscopic appendectomy was performed, but pathologic analysis demonstrated a type 2 appendiceal diverticulitis.

CONCLUSION

Appendiceal diverticulosis disease should be included in differential diagnosis of patients presenting with clinical signs of an acute appendicitis and prompt surgical treatment is essential in order to avoid severe complications.

Macroscopic and microscopic characteristics of low grade appendiceal mucinous neoplasms (LAMN) on appendectomy specimens and correlations with pseudomyxoma peritonei development risk

Low grade appendiceal mucinous neoplasm (LAMN) is the primary source of pseudomyxoma peritonei (PMP). PMP may develop after seemingly complete resection of primary tumor by appendectomy, which is unpredictable due to lack of reliable prognostic indicators. We retrospectively reviewed 154 surgically resected LAMNs to explore if any of the macroscopic and microscopic characteristics may be associated with increasing risk of PMP development. Our major findings include: (1) As compared to those without PMP, the cases that developed PMP were more frequent to have (a) smaller luminal diameter (<1 cm) and thicker wall, separate mucin aggregations, and microscopic perforation/rupture, all suggestive of luminal mucin leakage; (b) microscopic acellular mucin presenting on serosal surface and not being confined to mucosa; and (c) neoplastic epithelium dissecting outward beyond mucosa, however, with similar frequency of neoplastic cells being present in muscularis propria. (2) Involvement of neoplastic cells or/and acellular mucin at surgical margin did not necessarily lead to tumor recurrence or subsequent PMP, and clear margin did not absolutely prevent PMP development. (3) Coexisting diverticulum, resulted from neoplastic or non-neoplastic mucosa being herniated through muscle-lacking vascular hiatus of appendiceal wall, was seen in a quarter of LAMN cases, regardless of PMP. The diverticular portion of tumor involvement was often the weakest point where rupture occurred. In conclusion, proper evaluation of surgical specimens with search for mucin and neoplastic cells on serosa and for microscopic perforation, which are of prognostic significance, should be emphasized.

Imaging in Appendicular Diverticulosis with Appendicitis

Appendicular diverticulosis (AD) is an extremely rare condition. They are either incidentally detected in a normal or inflamed appendix or as diverticulitis manifesting clinically as appendicitis. It is commonly a radiological or pathological diagnosis. On computed tomography (CT), AD can mimic focal perforation. There are reported associations between AD and appendicular adenocarcinoma. This case reports the classical features of AD on CT with background appendicitis.

Appendiceal diverticulosis in a patient with family history of Birt-Hogg-Dubé syndrome--a case report

Birt-Hogg-Dubé syndrome (BHD) is a rare autosomal dominant disorder that predisposes patients to cutaneous tumors, pulmonary cysts with recurrent spontaneous pneumothoraces, and a variety of renal neoplasms including hybrid oncocytic and chromophobe renal cell carcinomas. There has been much debate regarding the genetic link with the occurrence of colorectal cancer and other colonic anomalies. Associations between BHD and intestinal adenomatous polyposis and sigmoid diverticulosis have been described in the literature, but there have been no prior reports of appendiceal diverticulosis in patients with BHD. Here, we present a 40-year-old female patient with a known family history of BHD, who was found to have diverticulosis of the appendix and pulmonary blebs on computed tomography upon routine screening for renal and pulmonary abnormalities, suggesting additional focus be given to the gastrointestinal tract (including the appendix) at the time of CT assessment.

Appendiceal neurofibroma and diverticula in a neurofibromatosis type 1 patient with chronic right lower quadrant pain

Neurofibromatosis type 1 (NF1, Von Recklinghausen disease) is an autosomal dominant disease with a birth incidence of 1/2500-3000. The most common presentations of NF1 are cutaneous presentations like café-au-lait spots and neurofibromas. 5%-25% of patients with NF1 have gastrointestinal manifestations of the disease. Appendiceal neurofibroma are extremely rare and only a few cases are described in literature. An appendectomy is indicated because of high risk of appendicitis and malignant transformation. We report the case of a 74-year-old male patient with a history of NF1 with chronic right lower quadrant pain. Successive imaging scans showed suspicion of chronic appendicitis. A diagnostic laparoscopy, resulting in a laparoscopic appendectomy was performed without complications. Histopathology showed appendiceal neurofibroma and diverticula. The postoperative course was uneventful. In patients with NF1 with right lower quadrant pain benign appendiceal neurofibroma should be included in the differential diagnosis. A diagnostic laparoscopy should be performed followed by an appendectomy.

Post-inflammatory mucosal hyperplasia and appendiceal diverticula simulate features of low-grade appendiceal mucinous neoplasms

Post-inflammatory mucosal hyperplasia and appendiceal diverticulosis simulate mucinous neoplasms, causing diagnostic confusion. Distinction between neoplasia and its mimics is particularly important since many authorities now consider all appendiceal mucinous neoplasms to be potentially malignant. The purpose of this study was to identify clinicopathologic and molecular features that may distinguish appendiceal mucinous neoplasms from non-neoplastic mimics. We retrospectively identified 92 mucinous lesions confined to the right lower quadrant, including 55 non-neoplastic examples of mucosal hyperplasia and/or diverticulosis and 37 low-grade neoplasms. Presenting symptoms, radiographic findings, appendiceal diameter, appearances of the lamina propria, non-neoplastic crypts, and epithelium, as well as mural changes were recorded. Twenty non-neoplastic lesions were subjected to KRAS mutational testing. Non-neoplastic appendices were smaller (p < 0.05) and more likely to present with symptoms of appendicitis (p < 0.05) than neoplasms. While post-inflammatory mucosal hyperplasia and diverticula often showed goblet cell-rich epithelium, extruded mucin pools, and patchy mural alterations with fibrosis, they always contained non-neoplastic crypts lined by mixed epithelial cell types and separated by lamina propria with predominantly preserved wall architecture. On the other hand, mucinous neoplasms lacked normal crypts (p < 0.05) and showed decreased lamina propria (p < 0.05) with diffusely thickened muscularis mucosae and lymphoid atrophy. Six (30%) non-neoplastic lesions contained KRAS mutations, particularly those containing goblet cell-rich hyperplastic epithelium. We conclude that distinction between neoplastic and non-neoplastic mucinous appendiceal lesions requires recognition of key morphologic features; KRAS mutational testing is an unreliable biomarker that cannot be used to assess biologic risk or confirm a diagnosis of neoplasia.

Systematic review and meta-analysis of the association between diverticulosis of the appendix and neoplasia

BACKGROUND

Diverticula of the appendix (DA) are infrequent and their clinical implications are often overlooked. Several studies have found a significantly increased prevalence of neoplasms in appendiceal specimens with diverticula. Despite the potential clinical implications, there is a paucity of literature. A systematic review and meta-analysis was performed to evaluate the prevalence of DA and its association with neoplasia.

METHODS

A systematic search of literature (Cochrane, EMBASE, PubMed and Medline) reporting the prevalence of DA and association with neoplasia was performed in November 2019. Relevant articles were assessed in accordance with the PRISMA guidelines. Risk of bias assessment was carried out using modified Newcastle-Ottawa scale. Meta-analysis with risk ratio and random-effects model was performed using RevMan.

RESULTS

The initial search identified 1122 potential articles of which 11 were appropriate for quantitative analysis. The prevalence rate of DA was 1.74%. The mean age of patients with DA and those without DA was 41.2 and 33.9 years, respectively. The ratio of male to female was 1.8:1. The prevalence of neoplasia in specimens without DA versus those with DA was 1.28% and 26.94%, respectively. Only four studies addressed the prevalence of locoregional neoplasia in the setting of DA compared to control. Meta-analysis with random-effects model demonstrated that pooled risk ratio was 25.46 (95% confidence interval 12.77-50.75, P < 0.00001).

CONCLUSION

The strong association with neoplasia in this meta-analysis reinforces the clinical significance of DA. Surgeons, pathologists and radiologists should be mindful of this uncommon pathology and consider individualized patient management, until further evidence can direct clinical guidelines for the management of patients with DA.

Diagnosis of appendiceal diverticulitis by multidetector computed tomography

PURPOSE

Because appendiceal diverticulitis (AD) has a high risk of perforation, precise diagnosis is important for patients with suspected acute appendicitis (AA). In this study, we aimed to reveal the characteristics of computed tomography (CT) images of AD.

METHODS

CT images were comparatively analyzed in patients who underwent appendectomy and had histopathologically proved AD (n = 23) or AA (n = 365) to reveal specific findings of CT image for AD and determine sensitivity and specificity of CT for AD.

RESULTS

Univariate analysis showed that maximal diameter of the appendix in AD was significantly smaller than that in AA. Multivariate analysis showed that saccular structure of the appendix wall, cecum or ascending colon diverticulum and peri-appendiceal or -cecal fluid collection were significant independent indicators of AD. Based on that saccular structure of the appendix wall which was the most important specific finding, the sensitivity and specificity of CT for AD were 48% and 99%, respectively.

CONCLUSION

The saccular structure of the appendix wall, cecum or ascending colon diverticulum and peri-appendiceal or -cecal fluid collection in CT suggest AD in patients with suspected AA. The sensitivity and specificity of CT for diagnosing AD were 48% and 99%, respectively.

Appendiceal diverticulitis presenting as acute appendicitis diagnosed postoperatively

Appendiceal diverticular disease is a rare entity. We report a case of appendiceal diverticulitis mimicking acute appendicitis and diagnosed postoperatively on histopathology. A 28-year-old female presented with a 2-day history of shifting periumbilical pain associated with nausea and anorexia. A computed tomography scan of the abdomen demonstrated acute appendicitis. She was taken to laparoscopic appendectomy. Histopathology showed appendiceal diverticulitis, and perforation of an inflamed diverticulum with periappendicitis. Diverticulosis of the appendix is classified as congenital and acquired. Diagnosis can be made preoperatively by imaging. In this case, diverticulosis was not radiologically evident, and was interpreted as acute appendicitis. Gross appearance of the resected appendix was not suggestive of diverticulitis. Other cases reported that the gross specimen had evidence of diverticular disease. Surgeons should be aware that inflamed appendixes may harbor different pathologies warranting further management.

Clinical characteristics of appendiceal diverticular disease

BACKGROUND

Appendiceal diverticular disease (ADD) is a rare pathology which is associated with an increased mortality risk due to rapid perforation and high rates of neoplasm. In our study, we aimed to evaluate the clinical and histopathological characteristics of ADD with differences from acute appendicitis (AA) diagnosis and to determine the association with neoformative processes.

METHODS

The 4279 patients who underwent appendectomy were evaluated retrospectively. ADD patients histopathologically classified into four groups. Patients' demographic characteristics, imaging and preoperative laboratory findings, additionally postoperative histopathology results were compared between groups.

RESULTS

The prevalence of ADD was 2.29% (n = 98). In addition, the male/female ratio was 2.37 in ADD patients who were found to be significantly older than those with AA patients. Type III was the most frequently (62.2%) identified sub-group of ADD. The incidence of neoplasms, plastrone, and Littre's hernia was found statistically higher in ADD group than AA group. Mucinous adenomas (10.2%) was the most common neoplasm while the carcinoid tumor (1%) and precancerous serrated adenomas (4.1%) were also reported.

CONCLUSIONS

As a result, high neoplasm in ADD patients can be shown with incidence of perforation and plastron, and in order to avoid possible neoplasm or major complications, it is necessary to carry out new studies for the right diagnosis of ADD whether the diagnosis is done preoperatively or ıntraoperatively. We recommend surgical resection of the ADD, which may even be incidentally detected during any surgical procedure, due to its high risk of neoplasm and rapid perforation.

Clinical significance of appendiceal diverticulum: a significant marker for appendiceal neoplasia in Australian patients

INTRODUCTION

Diverticula of the appendix (DA) have a reported incidence of up to 2.1%. They are primarily detected incidentally, through imaging and intraoperative or histologic diagnosis. This study's objective was to examine the prevalence of DA, and its relationship with inflammation and neoplasia, as well as review the literature with respect to clinical outcomes and ability to identify DA preoperatively.

METHODOLOGY

A retrospective search of all patients undergoing an appendicectomy for right lower quadrant pain at a single institution between 2004 and 2017 was conducted. Histopathology reports for evidence of DA, location of the DA, presence of inflammation, and any relationship between DA and neoplasms (adenoma, carcinoma, carcinoid, lymphoma, and mucinous neoplasm) within the appendix were reviewed. Clinical notes, operative records, and preoperative imaging were also reviewed.

RESULTS

Two thousand seven hundred eleven patient were included in the study, with a mean age of 34 years, with acute appendicitis found in 82.5%. 31.6% of patients with DA had associated inflammation of the DA. DA was present in 57 patients (2.1%), with 55 patients in the total cohort having neoplasia (2.0%). Patients with DAs were ten times more likely to have appendicular neoplasm than patients without a DA (17.5 vs 1.8%; p < 0.0001, OR 11.8 95%, CI 5.6-24.8).

CONCLUSION

This is the first Australian study demonstrating DAs are a significant marker of appendiceal neoplasm. Appendicectomy in all incidentally discovered diverticulum should be considered. Due to a paucity of data, research is required into this area to assess for the need for endoscopy following diagnosis.

Appendiceal diverticulosis: a harbinger of underlying primary appendiceal adenocarcinoma?

Diagnosis of primary appendiceal adenocarcinoma (PAA) is hindered by its rarity and largely asymptomatic nature. Appendiceal diverticulosis (AD) is equally rare. We report an unusual case of PAA presenting with perforated appendiceal diverticulitis, and discuss a review of the literature about its association, and its surgical and pathological implications. A middle-aged man was admitted with right iliac fossa (RIF) pain and a corresponding tender abdominal mass for 5 days. Computerised tomography (CT) scan demonstrated a thickened appendix with 3 cm abscess at its base. During laparoscopic appendicectomy, the appendiceal phlegmon was adhered to the surrounding bowel. Histology showed a perforated diverticulum near the appendiceal tip, and a primary appendiceal well-differentiated adenocarcinoma located proximal to it with clear margins. Up to 48% of ADs are associated with appendiceal neoplasms, but its coexistence with PAA is reported in fewer than ten instances worldwide. Obstructing appendiceal tumours, by raising intraluminal pressure, can predispose to AD formation. Intestinal-type PAA is often managed like its colorectal counterpart, although controversies about management of PAA in a perforated AD remain. Recognition of the association of AD and PAA is critical to ensure meticulous oncological resection and histological examination.

Unexpected histopathology of acute appendicitis

INTRODUCTION

Appendicular diverticula and associated diverticulitis is a rare disease. Patients present commonly with symptoms of acute appendicitis and require laparoscopic or open surgery. Diagnosis is usually made only on histology. Here, we present a rare case of acute diverticulitis of the appendix.

CASE PRESENTATION

A 33-year old gentleman presented with right iliac fossa pain of 3 days duration. On admission, appendicitis was diagnosed on Computerized Tomography (CT) scan and laparoscopic appendicectomy was subsequently performed. Intra-operative findings were unremarkable and recovery was uneventful. Histopathology however revealed diverticulitis of appendix with acellular mucin.

DISCUSSION

Acute diverticulitis of the appendix is an exceptionally rare condition and reported in 0.004%-2% of appendicectomies. It presents usually when complicated with perforation and bleeding. There is however a strong association with certain malignancies such as mucinous neoplasm, carcinoid and Pseudomyxoma peritoneii. Radiological proven appendicular diverticulum requires early intervention due to higher chance of diverticulitis related complication. Surgeons should be aware about this rare disease and may consider elective surgery in view of potential risk of complications and malignancy.

CONCLUSION

We concluded that because of strong malignant association, it would be recommended that all appendix specimens should inspect during and after surgery and concurrent examination of peritoneal cavity is recommended.

Appendiceal diverticulitis, a rare relevant pathology: Presentation of a case report and review of the literature

•

Appendiceal diverticulitis is often overlooked with high risk of perforation.

•

Appendiceal diverticula is often associated to appendiceal neoplasm.

•

Accurate appendectomy should be performed in order to permit appropriate pathological examination.

•

Prophylactic appendectomy should be performed in asymptomatic patients with appendiceal.

Introduction

Appendiceal diverticulitis is a rare pathology that mimics acute appendicitis. Appendiceal diverticula are classified into congenital and acquired with difference in incidence and pathogenesis. Appendiceal diverticulitis is often overlooked because of mildness of symptomatology with increasing risk of complications, such as perforation. Appendiceal diverticula are often associated to higher risk of neoplasm especially carcinoid tumors and mucinous adenomas.

Presentation of case

A 40-year-old caucasic male presented into Emergency Room with right lower quadrant pain associated with vomit, abdominal tenderness, fever and moderate leukocytosis (11.93 × 10; neutrophils 78.5%). Acute appendicitis was suspected and a surgical approach was chosen with a McBurney access. The removed specimen (Figs. 1 and 2) was 11 cm long with multiple hyperaemic and oedematous diverticular protrusions. The postoperative course was regular. Discharging was on 4th postoperative day in optimal clinical conditions. The histological examination (Fig. 3) showed acute inflammation of appendiceal pseudodiverticula with acute peridiverticulitis and abscess.

Discussion

Currently, appendiceal diverticulitis is often overlooked with high risk of complications, above all perforation. Attention should be kept during the surgical procedure and the patholological examination in order to identify any associated neoplasm.

Conclusion

Appendiceal diverticulitis should be considered in adult male patients with right lower quadrant pain or tenderness. Accurate appendectomy should be performed in order to permit an appropriate pathological examination and possible associate neoplasm should always be searched through. Prophylactic appendectomy should be performed in case of incidental finding of appendiceal diverticula in asymptomatic patients in order to avoid the high perforation risk.

Beyond appendicitis; radiologic review of unusual and rare pathology of the appendix

Appendicitis is a very common cause of acute abdominal pathology, however, many other pathologic conditions of the appendix can be diagnosed utilizing CT. Examples of these conditions include primary appendiceal neoplasms, secondary inflammation of the appendix, stump appendicitis, endometriosis, appendicitis within a hernia, appendiceal diverticulosis and intussusception and intraluminal foreign bodies. The purpose of this article is to review appendiceal pathology outside of acute appendicitis, describe corresponding imaging findings on CT, and to illustrate various CT findings of appendiceal disease with representative cases.

Perforated appendiceal diverticulitis associated with appendiceal neurofibroma in neurofibromatosis type 1

An appendiceal neurofibroma (ANF) is a rare neoplasm associated with neurofibromatosis type 1(NF-1), an inheritable neurocutaneous disorder that involves multiple systems including the intraabdominal organs. Appendiceal diverticulitis occasionally ruptures in the absence of intense abdominal pain, which can lead to serious consequences. Recent reports highlight the association between appendiceal diverticulum and appendiceal neoplasms; however, there is still little information on the association between appendiceal diverticulitis and ANF in NF-1. A 51-year-old Japanese male with NF-1 was referred to the division of surgery for mild right lower quadrant pain. It was suspected he had perforated acute appendicitis with periappendiceal abscess based on clinical manifestations and findings of computed tomography. An emergency appendectomy was conducted. The pathological examination revealed diffusely proliferated tumor cells of a neurofibroma, coexistent with multiple appendiceal diverticulums, leading to the diagnosis of perforated appendiceal diverticulitis associated with ANF. Although he developed a remnant abscess, he recovered with the conservative treatments of antibiotics and drainage. This case suggests that appendiceal diverticulitis might be a complication of appendiceal involvement of NF-1, and that it occasionally ruptures in the absence of intense abdominal pain. Clinicians should recognize that NF-1 can cause various abdominal manifestations.

Low-grade mucinous neoplasia in a cecal diverticulum: A case report

INTRODUCTION

Low-grade mucinous neoplasia is an uncommon benign tumor that develops in the appendix. The development of mucocele disease has never been reported in a colonic diverticulum. We present a case developing low-grade mucinous neoplasia in a cecal diverticulum.

PRESENTATION OF CASE

A tumor in the ileocecal region was found during a medical examination of a 66-year-old woman. Three months later, the tumor was still present and the patient developed abdominal pain. Laparoscopic ileocecal resection with D2 lymph node dissection was performed. Histopathological examination revealed a low-grade mucinous neoplasm in a cecal diverticulum.

DISCUSSION

Colonic mucoceles reportedly originate from the appendix. There are no previous reports of mucocele disease in a colonic diverticulum worldwide. This report reviews and discusses the management of the appendiceal mucoceles.

CONCLUSION

The incidence of colonic diverticula has recently begun to increase in Japan. The possibility of a mucocele within a colonic diverticulum should be considered in patients with submucosal colonic tumors.

Appendiceal diverticulitis clinically masquerading as an appendiceal carcinoma

Appendiceal diverticulosis is a rare condition. Herein reported is a case of appendiceal diverticulosis and diverticulitis clinically masquerading as appendiceal carcinoma. A 62-year-old woman presented with abdominal pain. US and CT showed a tumor measuring 5 × 4 × 4 cm in vermiform appendix. Colon endoscopy showed mucosal elevation and irregularity in the orifice of vermiform appendix. A biopsy of the appendiceal mucosa showed no significant changes. Clinical diagnosis was appendiceal carcinoma and wide excision of terminal ileum, appendix, cecum, and ascending colon was performed. Grossly, the appendix showed a tumor measuring 5 × 3 × 4 cm. The appendiceal lumen was opened, and the appendiceal mucosa was elevated and irregular. The periappendiceal tissue showed thickening. Microscopically, the lesion was multiple appendiceal diverticula. The diverticula were penetrating the muscle layer. The mucosa showed erosions in places. Much fibrosis, abscess formations, and lymphocytic infiltration were seen in the subserosa. Abscesses were also seen in the diverticular lumens. Some diverticula penetrated into the subserosa. The pathologic diagnosis was appendiceal diverticulitis. When they encounter an appendiceal mass, clinicians should consider appendiceal diverticulitis as a differential diagnosis.

Clinical implications of diverticular disease of the appendix. Experience over the past 10 years

BACKGROUND

Diverticular disease of the appendix is an uncommon condition, with an incidence from 0.004 to 2.1%. It usually occurs between the fourth or fifth decades of life, does not present gastrointestinal symptoms but only insidious abdominal pain. Patients usually delay consultation, leading to increased morbidity and mortality. The aim of this study was to determine the clinical features of diverticular disease of the appendix.

METHODS

A retrospective study of all patients undergoing appendectomy in a tertiary hospital between September 2003 and September 2013 was performed.

RESULTS

During this period, 7,044 appendectomies were performed, and 42 cases of diverticular disease of the appendix were found, which represents an incidence of 0.59%. A total of 27 patients were male. The mean age was 46.6±21 years. The average hospital stay was 4.5 days. A perforated appendix was identified in 46% of patients. In 80% of the cases, a complementary imaging test was performed. The incidence of neoplastic disease with diverticulum of the appendix was 7.1%.

CONCLUSIONS

Diverticular disease of the appendix is an incidental finding. In its acute phase, it presents as an acute appendicitis. The treatment of choice is appendectomy. It presents a higher risk of developing neoplastic disease of the appendix.

[Peritoneal pseudomyxoma: an overview emphasizing pathological assessment and therapeutic strategies]

Pseudomyxoma peritonei is a clinical entity characterized by a gelatinous ascite associated with mucinous tumor deposits spreading on peritoneal surface and potentially invading abdominal organs. It is considered as a tumor process linked, in most of cases, to a mucinous appendiceal neoplasm. Pseudomyxoma peritonei may benefit from a therapeutic strategy combining cytoreductive surgery and intra-peritoneal chemotherapy, which has led to a major prognosis improvement. Different classifications are available and the last one corresponds to the WHO 2010 version, which individualizes pseudomyxoma peritonei in two classes: low grade and high grade mucinous carcinoma. The very low frequency of this entity and its specific therapeutic strategy need specific health care centres, as well as physicians and pathologists collaborating through dedicated networks. The aim of this article is to summarize the pathology, causes, mechanisms and therapeutic approaches of pseudomyxoma peritonei, as well as their interfaces with dedicated networks.

Clinicopathological study of 25 cases of diverticular disease of the appendix: experience from farwaniya hospital

Background. Diverticular disease of the appendix (DDA) is a rare disease and it has been shown to be associated with locoregional neoplasms. This study was conducted to characterize clinicopathological features and to investigate its association with appendiceal neoplasms. Methods. We searched the records of the Department of Pathology at Farwaniya Hospital for cases of diverticular disease of the appendix between 2003 and 2011. Histological slides and patient charts were reviewed for relevant information. Consecutive cases of acute appendicitis were selected as a control group. Results. We identified 25 cases of DDA, 24 of which occurred in men. Mean age of DDA patients was 35 ± 10.1 years and was significantly greater than that of appendicitis patients (P = 0.027). The mean temperature of cases (37.9°) was significantly higher (P = 0.012) than that of the controls (37.3°). The cases had lower white blood cell (WBC) counts compared to controls (13.6 versus 16.7, P = 0.04). Pathological diagnosis identified 4 cases of diverticulosis, 5 cases of diverticulitis, 6 cases of diverticulosis with acute appendicitis, and 10 cases of diverticulitis and appendicitis. None of the cases was associated with any type of neoplasm. Conclusions. DDA is a rare disease, and clinicians and radiologists should be aware of it. Male sex and adult age seem to be risk factors associated with DDA. The disease may not have any direct association with any neoplasm.

Appendiceal Mucosal Schwann Cell Proliferation

Recognition of an appendiceal diverticulum is important because of its association with an appendiceal neoplasm. The incidence of mucosal Schwann cell proliferation in 24 cases of appendiceal diverticular disease, 17 serrated polyps, 4 cases of mucosal hyperplasia, and 45 normal appendices was determined. Ten (42%) of 24 cases with diverticula, 2 (50%) of 4 cases of mucosal hyperplasia with concurrent surface low-grade dysplasia, and 9 (20%) of 45 cases of normal appendices showed mucosal Schwann cell proliferation. It was not seen within the 17 cases of serrated polyps. Mucosal Schwann cell proliferation is common in appendiceal diverticular disease and may serve as a histologic marker for the presence of an appendiceal diverticulum. Thus, when routine histologic sections of a removed appendix demonstrate Schwann cell proliferation, further examination of the specimen may detect possible coexisting diverticular disease, which in turn may be associated with appendiceal neoplasms and epithelial dysplasia.