Anatomical variants and pathologies of the vermix

Left-sided appendicitis managed laparoscopically: a case report

BACKGROUND

Appendicitis is one of the most common causes of acute abdominal pain and remains the most common abdominal-related emergency seen in emergency room that needs urgent surgery (Yang et al. in J Emerg Med 43:980-2, 2012. 10.1016/j.jemermed.2010.11.056, Wickramasinghe et al. in World J Surg 45:1999-2008, 2021. 10.1007/s00268-021-06077-5). The characteristic presentation is a vague epigastric or periumbilical discomfort or pain that migrates to the lower right quadrant in 50% of cases. Other related symptoms, such as nausea, anorexia, vomiting, and change in bowel habits, occur in varying percentages. The diagnosis is usually reached through comprehensive history, physical examination, laboratory tests, and radiological investigations as needed. Nowadays, computed tomography of the abdomen and pelvis is considered the modality of choice for definitive assessment of patients being evaluated for possible appendicitis. Anatomical variations or an ectopic appendix are rarely reported or highlighted in literature.

CASE PRESENTATION

Left-sided appendicitis is a rare (Hu et al. in Front Surg 2022. 10.3389/fsurg.2022.896116) and atypical presentation and has rarely been reported. The majority of these cases are associated with congenital midgut malrotation, situs inversus, or an extremely long appendix (Akbulut et al. in World J Gastroenterol 16:5598-5602, 2010. 10.3748/wjg.v16.i44.5598). This case is of significance to raise awareness regarding an anatomical variation of the appendix that might delay or mislead diagnosis of appendicitis and to confirm safety of a laparoscopic approach in dealing with a left-sided appendicitis case (Yang et al. in J Emerg Med 43:980-2, 2012. 10.1016/j.jemermed.2010.11.056). We report a case of left-sided appendicitis in a 12-year-old child managed successfully via a laparoscopic approach.

CONCLUSION

Appendicitis remains the most common abdominal-related emergency that needs urgent surgery (Akbulut et al. in World J Gastroenterol 16:5598-5602, 2010. 10.3748/wjg.v16.i44.5598). Left-sided appendicitis is a rare (Hu et al. in Front Surg 2022. 10.3389/fsurg.2022.896116, Hu et al. in Front Surg 9:896116, 2022. 10.3389/fsurg.2022.896116) and atypical presentation and has rarely been reported. Awareness regarding an anatomical variation of the appendix and diagnostic modalities on a computed tomography scan help avoid delay in diagnosis and management of such a rare entity (Vieira et al. in J Coloproctol 39(03):279-287, 2019. 10.1016/j.jcol.2019.04.003). A laparoscopic approach is a safe approach for management of left-sided appendicitis (Yang et al. in J Emerg Med 43:980-2, 2012. 10.1016/j.jemermed.2010.11.056, Hu et al. in Front Surg 9:896116, 2022. 10.3389/fsurg.2022.896116).

Computed tomography evaluation of variations in positions and measurements of appendix in patients with non-appendicular symptoms: time to revise the diagnostic criteria for appendicitis

Purpose

To estimate the frequency distribution of different anatomical positions, and to measure the diameter, wall thickness, and length of appendix in patients with non-appendicular symptoms.

Material and methods

This retrospective observational study was conducted among 1,575 patients, who had undergone computed tomography (CT) scan of abdomen for various non-appendicular signs and symptoms. Frequency of distribution of different anatomic locations and measurements of various morphologic parameters were recorded.

Results

The most common location of appendix was retrocecal, followed by sub-cecal, post-ileal, and pelvic locations. The mean length of appendix was 66.7 mm (range, 6.3-123 mm), and the diameter was 6.3 mm (range, 2.8-11.3 mm). Diameter of > 6 mm was noted in 48.12% patients. The mean wall thickness was 2.37 mm, ranging 1.2-4.2 mm. The most common intra-luminal content was air-mixed with hypodense or hyperdense material observed in 70.5% of cases.

Conclusions

Although an appendix with diameter less than 6 mm may be considered normal, a diameter above 6 mm has an overlap between a normal and inflamed appendix. Therefore, it should be considered in association with clinical and secondary findings to avoid overdiagnosis and unnecessary appendicectomies. We strongly recommend that diameter-based CT criteria to diagnose appendicitis should be revised and standardized.

The Vermiform Appendix and Its Pathologies

The vermiform appendix is a muscular cylindrical structure originating near the junction of the cecum and ileum, averaging 9 cm (5-35 cm) in size. As the most mobile viscera, it can adopt several positions, the most common being the retrocecal position. Perceived as an atavistic organ lacking physiological relevance, the vermiform appendix appears to be involved in immune function, serving in the maturation of B lymphocytes and the production of immunoglobulin A, in endocrine function, excreting amines and hormones in the 2-3 mL of mucus secreted daily, and in digestive function, by storing beneficial bacteria from where they can recolonize the colon. With a lumen of about 6 mm, the vermiform appendix has a reduced storage capacity, so any blockage of the appendix with fecoliths (fecaliths), seeds derailed from the colon, or enlarged lymph nodes prevents drainage and intraluminal accumulation of secreted mucus. Unable to relax, the appendix wall severely limits its intraluminal volume, so mucus accumulation leads to inflammation of the appendix, known generically as appendicitis. In addition, the vermiform appendix may be the site of the development of neoplastic processes, which may or may not involve mucus production, some of which can significantly affect the standard of living and ultimately lead to death. In general, mucinous tumors may have a better prognosis than non-mucinous tumors. This review takes a comprehensive path, starting by describing the anatomy and embryology of the vermiform appendix and further detailing its inflammatory pathologies, pathologies related to congenital anomalies, and appendix tumors, thus creating an up-to-date framework for better understanding, diagnosis, and treatment of these health problems.

Landscape of Genetic Mutations in Appendiceal Cancers

In appendiceal cancers, the most frequently mutated genes are (i) KRAS, which, when reactivated, restores signal transduction via the RAS-RAF-MEK-ERK signaling pathway and stimulates cell proliferation in the early stages of tumor transformation, and then angiogenesis; (ii) TP53, whose inactivation leads to the inhibition of programmed cell death; (iii) GNAS, which, when reactivated, links the cAMP pathway to the RAS-RAF-MEK-ERK signaling pathway, stimulating cell proliferation and angiogenesis; (iv) SMAD4, exhibiting typical tumor-suppressive activity, blocking the transmission of oncogenic TGFB signals via the SMAD2/SMAD3 heterodimer; and (v) BRAF, which is part of the RAS-RAF-MEK-ERK signaling pathway. Diverse mutations are reported in other genes, which are part of secondary or less critical signaling pathways for tumor progression, but which amplify the phenotypic diversity of appendiceal cancers. In this review, we will present the main genetic mutations involved in appendix tumors and their roles in cell proliferation and survival, and in tumor invasiveness, angiogenesis, and acquired resistance to anti-growth signals.

Variant anatomy of non-recurrent laryngeal nerve: when and how should it be taught in surgical residency?

INTRODUCTION

While the performance of a thyroidectomy is generally associated with a low risk of injury to the recurrent laryngeal nerve (RLN), the presence of a non-recurrent nerve (NRLN) increases the risk of this complication. Generally, the intraoperative detection via visual appreciation of variant anatomy of the RLN has been regarded as poor, possibly due to a lack of knowledge of both the normal and aberrant anatomy of the RLN.

MATERIALS AND METHODS

Articles for the review were searched through PubMed using the search terms and their combinations: "non-recurrent laryngeal nerve," "thyroidectomy," "injury," "palsy," "variant anatomy," and "residency," from January 1, 2000, to December 2022. Papers considered for the review were the articles published in English, with additional classic and articles of surgical importance retrieved from the reference list of papers. Only papers relevant to the scope of the review were considered for this review.

FINDINGS

The NRLN has been found to be associated with concurrent vascular abnormalities, such as the presence of an aberrant right subclavian artery (ARSA) or an arteria lusoria originating from the aortic arch. However, it seems that both the normal as well as aberrant anatomy of the RLN is currently not emphasized enough during postgraduate surgical training. With the increased use of intraoperative neuromonitoring (IONM), detection of NRLN has become possible through appropriate neural mapping during thyroid surgery, besides other pointers such as visualization during surgery, computerised tomography, and duplex ultrasound scans to visualize the variant vascular anatomy. There is also a possible role for cadaveric courses, either during medical school or in a post-graduate setting-adapted to the student's level to teach the variant anatomy. With the development of newer techniques such as artificial intelligence, there are potential new options for teaching and training anatomy in the near future.

CONCLUSIONS AND RELEVANCE

Adequate knowledge of the normal and aberrant anatomy of the RLN remains essential for the best outcomes in thyroid surgery, even in the era of the IONM. Moving forward, the knowledge of (aberrant) anatomy should be made an integral part of the core competencies of both medical students and surgical trainees. It is imperative that leaders of the different field work closely together to combine their knowledge towards providing their trainees with the best possible training options.

A peculiar appendix: A case report

Introduction and importance

Acute appendicitis is a clinical diagnosis with marked variations in the clinical presentation, the latter resultant of varied anatomical positions of the appendix.

Presentation of case

Here we present the first documented case of the vermiform appendix located in the ascending colon of a young South Asian male who presented with right upper abdominal pain. The ultrasound scan of the abdomen failed to visualise the appendix in the right iliac fossa. Persistent symptoms despite conservative therapy and elevated inflammatory markers warranted an open laparotomy. The histology further confirmed acute appendicitis.

Clinical discussion

Atypical locations and congenital anomalies of the appendix are relatively rare entities. Appendicular duplication and hypoplasia are the predominant varieties of congenital anomalies. Caecal diverticula might mimic acute appendicitis despite the relative rarity and absence of all three layers of intestinal wall, which could be of use in distinguishing an abnormally located appendix.

Conclusion

Such deviations from the norm lead to atypical clinical and imaging findings where operative interventions might be required in place of non-operative care, especially in instances of persistent symptomatology.

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Human appendix has a variable course although congenital anomalies related to its position are rare

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Unusual anatomical positions lead to atypical presentations and negative/abnormal findings in appendicular pathology.

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Hypoplasia, agenesis, duplication, triplication and diverticular formation are rare congenital anomalies of the appendix.

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Appendix located in the ascending colon has never been reported in the English literature so far.

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

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

Appendiceal neoplasms and histological involvement of the mesoappendix: A case series

Introduction

Acute appendicitis is a common presentation to surgical departments, typically resulting in appendicectomy. Appendiceal tumours may not be visible intraoperatively, and are present in roughly 0.5–1% of specimens. Routine resection of the mesoappendix is not universally practiced, despite the mesoappendix being commonly involved in appendiceal tumours.

This is a case series of the histological findings of 21 patients with appendiceal tumours, with consideration to tumour within the resected mesoappendix.

Methods

We reviewed the histology of 1344 patients undergoing laparoscopic appendicectomy over a 6-year period assessing for the presence of appendiceal tumours and resected mesoappendix.

Results

Twenty-one patients were found to have appendiceal tumours, with a mean maximum tumour dimension of 7.2 mm. Sixteen of these patients had simultaneous mesoappendix resection, of whom six (38%) were found to have direct or indirect tumour tissue within the mesoappendix.

Conclusion

Further evidence for routine removal of the mesoappendix, and the need for larger prospective studies to investigate for any survival benefit. We note the worrying trend of conservative management of acute appendicitis.

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The mesoappendix is a key site of appendiceal tumour spread, directly & indirectly.

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Routine mesoappendix resection may reduce the need for reoperation.

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Conservative management of appendicitis may delay diagnosis of appendiceal tumours.

Ureteral substitution with appendix

OBJECTIVE

To study the long-term results of ureteral reconstruction with the appendix in patients with long ureteral strictures.

METHODS

From 1998 to 2019, 26 patients were operated with substitution of extended defects of the ureter with the appendix. There were 22 women and four men (mean age 44.7 ± 11.3 years). One patient had stricture of the lumbar ureter because of a gunshot wound. He underwent substitution of the upper third of the right ureter with the appendix. In the other cases, we carried out substitution of the pelvis part of the ureter with appendix, in four cases from the left side. In the last 22 cases, a novel surgical technique for better appendicovesical anastomosis was carried out: a flap was dissected from the dome of the cecum to increase the diameter of anastomosis.

RESULTS

The postoperative follow-up period was from 1 to 21 years. A stricture of uretero-appendical anastomosis developed in four patients (15.4%). Resection of stricture and re-anastomosis was carried out in one case. In another two cases associated with similar complications, endoureterotomy and ureteral stenting were carried out. One patient was managed with percutaneous nephrostomy. Kidney function was restored in all patients. Good short-term results were achieved in 22 patients (84.6%) and long-term (from 1 to 21 years) results in 25 patients (96.2%).

CONCLUSIONS

In patients with long ureteral stricture, the use of the appendix can help to restore the function of the upper urinary tract.

AppendiXNet: Deep Learning for Diagnosis of Appendicitis from A Small Dataset of CT Exams Using Video Pretraining

The development of deep learning algorithms for complex tasks in digital medicine has relied on the availability of large labeled training datasets, usually containing hundreds of thousands of examples. The purpose of this study was to develop a 3D deep learning model, AppendiXNet, to detect appendicitis, one of the most common life-threatening abdominal emergencies, using a small training dataset of less than 500 training CT exams. We explored whether pretraining the model on a large collection of natural videos would improve the performance of the model over training the model from scratch. AppendiXNet was pretrained on a large collection of YouTube videos called Kinetics, consisting of approximately 500,000 video clips and annotated for one of 600 human action classes, and then fine-tuned on a small dataset of 438 CT scans annotated for appendicitis. We found that pretraining the 3D model on natural videos significantly improved the performance of the model from an AUC of 0.724 (95% CI 0.625, 0.823) to 0.810 (95% CI 0.725, 0.895). The application of deep learning to detect abnormalities on CT examinations using video pretraining could generalize effectively to other challenging cross-sectional medical imaging tasks when training data is limited.

Variations and morphometric features of the vermiform appendix: A systematic review and meta-analysis of 114,080 subjects with clinical implications

Determining the true and indisputable data regarding the vermiform appendix (VA) morphology is of a great clinical interest. The aim of this study was to provide the best evidence-based anatomical overview of the variations in location and size of VA using a systematic and meta-analytical approach. A systematic review with meta-analysis was performed of studies reporting variants of the location and morphometric data regarding the VA. The MEDLINE/PubMed, ScienceDirect, EMBASE, BIOSIS, SciELO, and Web of Science databases were thoroughly searched throughout June 2018. The reported locations of the body of the VA were re-classified into a new, standardized classification system divided into nine categories. The AQUA tool was used to assess the quality of included studies. The research was conducted following PRISMA guidelines and registered at PROPSERO database. Our meta-analysis included 242 studies (n = 114,080). Overall, the VA was most commonly found in the retrocecal location (32.1%, 95%CI: 29.2-35.1), followed by the pelvic (28.5%, 95%CI: 26.7-30.4) and ileal (14.5%, 95%CI: 11.8-17.7) locations. Subjects without known appendiceal pathologies had significantly smaller VA outer diameters (5.84 mm, 95%CI: 5.68-5.99) than patients diagnosed with acute appendicitis (10.64 mm, 95%CI: 10.14-11.15). The overall pooled mean length of the VA was 80.29 mm (95%CI: 76.68-83.89). Significant differences were found in size of the VA between imaging modalities. The results obtained from this evidence-based anatomy study will improve the clinical understanding of the VA anatomy, which in turn will have major implications for clinical practice. Clin. Anat. 32:85-98, 2019. © 2019 Wiley Periodicals, Inc.

A pictorial essay of the most atypical variants of the vermiform appendix position in computed tomography with their possible clinical implications

Purpose

The tip of the appendix may be located in various areas of the abdominal cavity due to its variable length and/or the changeable position of the caecum. Although in the case of an atypical position the tip is usually located behind the caecum, there are possible locations that occur very rarely. Therefore, in the case of appendicitis the symptoms may lead to the wrong diagnosis. The aim of this study is to present the most atypical locations of the tip of the appendix found on CT (computed tomography) scans and thus help to avoid misdiagnoses.

Imaging findings

The most unusual locations of the tip of the appendix found in healthy subjects included: left inferior quadrant, along the lower edge of the liver near the gallbladder and the right kidney, the tip touching the duodenum, the rectum or appendages, and a long appendix located in the scrotum as the content of a hernia. In these positions, appendicitis may mimic acute diverticulitis, cholecystitis, duodenal ulcer, duodenitis, enteritis, or adnexal or testis pathologies.

Conclusions

It is important to be aware of atypical locations of the appendix because appendicitis in an unusual area may mimic other acute abdominal diseases and delay the proper treatment.

Imaging Findings of the Unusual Presentations, Associations and Clinical Mimics of Acute Appendicitis

There are many kinds of unusual presentations or associations and clinical mimics of acute appendicitis, and definitive diagnosis requires knowledge of the imaging findings in some cases. The unusual presentations and associations of acute appendicitis included in this study are perforated appendicitis, acute appendicitis occurring in hernias, acute appendicitis with cystic endosalpingiosis, intussusception of appendix, and acute appendicitis with pregnancy. We also present uncommon gastrointestinal, urinary and gynecologic clinical mimics of acute appendicitis including anomalous congenital band, duplication cysts, giant Meckel's diverticulitis, inflammatory fibroid polyp, renal artery thrombosis, spontaneous urinary extravasation and OHVIRA syndrome. Familiarity with these entities may improve diagnostic accuracy and enable the quickest and most appropriate clinical management.

Neoplasms of the Appendix: Pictorial Review with Clinical and Pathologic Correlation

Appendiceal neoplasms are uncommon tumors of the gastrointestinal tract that may manifest with symptoms of appendicitis, right lower quadrant pain, or palpable mass, leading to imaging or surgical intervention. The majority of appendiceal masses consist of primary epithelial neoplasms and neuroendocrine tumors (NETs). Epithelial neoplasms-mucinous and nonmucinous types-are more often detected at imaging than NETs due to their larger size and propensity for peritoneal spread and metastatic disease. Epithelial mucinous neoplasms are defined by the presence of mucin, detected at radiologic and pathologic examination. A mucocele or pseudomyxoma peritonei from epithelial mucinous tumors are the two most common cross-sectional imaging findings of appendiceal mucinous neoplasms. Nonmucinous epithelial tumors are less common and manifest as masses similar to colonic-type malignancies. NETs are often discovered incidentally at appendectomy due to their small size and nonaggressive behavior. Imaging findings of primary appendiceal tumors may overlap with those of acute appendicitis. Additionally, an appendiceal mass may cause acute appendicitis, obscuring the underlying mass. Other neoplasms including lymphoma, sarcoma, mesenchymal and nerve sheath tumors, or secondary malignant involvement of the appendix are rare. Treatment depends on the histologic subtype and extent of disease. Detailed description of organ, nodal, and peritoneal involvement informs surgical management with the goal of complete cytoreduction. Novel treatments such as hyperthermic intraperitoneal chemotherapy have increased survival for patients with mucinous tumors. ^©RSNA, 2017.

Mimicry of Appendicitis Symptomatology in Congenital Anomalies and Diseases of the Genitourinary System and Pregnancy

INTRODUCTION

Appendicitis is a prevailing cause of acute abdomen, but is often difficult to diagnose due to its wide range of symptoms, anatomical variations, and developmental abnormalities. Urological disorders of the genitourinary tract may be closely related to appendicitis due to the close proximity of the appendix to the genitourinary tract. This review provides a summary of the urological complications and simulations of appendicitis. Both typical and urological symptoms of appendicitis are discussed, as well as recommended diagnostic and treatment methods.

METHODS

Medline searches were conducted via PubMed in order to incorporate data from the recent and early literature.

RESULTS

Urological manifestations of appendicitis affect the adrenal glands, kidney, retroperitoneum, ureter, bladder, prostate, scrotum, and penis. Appendicitis in pregnancy is difficult to diagnose due to variations in appendiceal position and trimester-specific symptoms. Ultrasound, CT, and MRI are used in diagnosis of appendicitis and its complications. Treatment of appendicitis may be done via open appendectomy or laparoscopic appendectomy. In some cases, other surgeries are required to treat urological complications, though surgery may be avoided completely in other cases.

CONCLUSION

Clinical presentation and complications of appendicitis vary among patients, especially when the genitourinary tract is involved. Appendicitis may mimic urological disorders and vice versa. Awareness of differential diagnosis and proper diagnostic techniques is important in preventing delayed diagnosis and possible complications. MRI is recommended for diagnosis of pregnant patients. Ultrasound is preferred in patients exhibiting typical symptoms.

Perforated Appendicitis: Assessment With Multidetector Computed Tomography

Appendicitis is one of the most common abdominal surgical emergencies. In some cases, the correct diagnosis may be challenging, owing to different conditions that can mimic this pathology. In this context, abdominal computed tomography (CT) is the imaging modality of choice, leading to an accurate diagnosis and to a reduction in unnecessary laparotomies. The diagnosis of perforated appendix is crucial, but the detection of the perforation signs by CT may not be so simple in the early process. The aim of this article is to review the multiple detector CT signs of perforated appendicitis.

Challenges in magnetic resonance imaging for suspected acute appendicitis in pregnant patients

The assessment of a gravid patient with abdominal pain is a clinical challenge, as one must consider not only the common etiologies for abdominal pain but also etiologies resulting from the pregnancy. Further complicating the assessment is the altered anatomy and physiology that result from the enlarged uterus displacing and compressing normal anatomical structures. This alteration of anatomy makes the symptoms of appendicitis more variable and thus the diagnosis more difficult. Appropriate and timely imaging can result in better patient outcomes, and when appendicitis is suspected, imaging investigation should not be delayed. This article reviews some of the challenges of magnetic resonance imaging in gravid patients with suspected appendicitis and presents strategies for imaging this population.