Changing trends in appendiceal pathology: a 16-year retrospective extension study of surgically removed appendices in a tropical teaching hospital.

A total of one thousand four hundred sixty-seven (1,467) appendicectomy samples were obtained and processed during the study period. There were 746 males and 721 females, resulting in a male-to-female ratio of 1.03:1. The patients’ ages ranged from 4 days to 94 years, with a mean age of 24.3 ± 17.6 years. The highest proportion of patients was in the 10–19-year age group (22.8%), followed closely by those under the age of 10 (22.6%) and the 20–29-year age group (21.1%). (Table  1 ). Table 1 Sociodemographic characteristics Age group (Years) Frequency (n = 1467) Percentage  < 10 331 22.6 10–19 334 22.8 20–29 309 21.1 30–39 217 14.8 40–49 214 8.5 50–59 84 5.7 60–69 43 2.9  ≥ 70 25 1.7 Mean ± SD 24.25 ± 17.6 Sex Male 746 50.9 Female 721 49.1 Appendectomy type Emergency 1056 72.0 Incidental 399 27.0 Interval 12 0.8 Sociodemographic characteristics The annual frequency of appendectomies performed between 2008 and 2023 showed year-to-year variation, with peaks in 2013, 2017, and 2019. Histologically confirmed AA was the predominant diagnosis across all years, and the total number of appendectomies was closely tracked. The number of patients with no pathological diagnosis remained consistently low throughout the study period. Between 2020 and 2023, both the total number of appendectomies and the number of confirmed AA cases declined. (Fig.  1 ). Fig. 1 Frequency of Appendectomy Outcomes over Time Frequency of Appendectomy Outcomes over Time Table 2 compares the histological findings from the appendectomy samples in the current and previous studies. AA remained the most common diagnosis, although there was a 10% decrease in its proportion (from 62.5% to 52.5%) (Fig.  2 ). There was also a decrease in the total proportion of histologically normal appendices by 4.8% (from 12.4% to 7.6%). However, the number of Lymphoid hyperplasia cases increased by 10% (from 19.4% to 29.4%). The rates of extra-appendiceal peritonitis and granulomatous inflammation remained similar. Chronic appendicitis and fibrous obliteration appeared only in the current study. Neoplastic lesions slightly increased by 0.8% (from 1.0% to 1.8%). (Table  2 ). Table 2 Pathologic findings in current and previous studies Histological Diagnosis Present study Previous study Acute appendicitis 770(52.5) 187(62.5) Appendix with hyperplasia 432(29.4) 58(19.4) Extra-appendiceal peritonitis 51(3.5) 11(3.7) Normal appendix 112(7.6) 37(12.4) Granulomatous inflammation 12(0.8) 3(1.0) Chronic appendicitis 16(1.1) 0 Fibrous obliteration 38(2.6) 0 Neoplastic Lesions 27(1.8) 3(1.0) Others 9(0.6) 0 1467 299 Fig. 2 Comparison of histopathologic findings in the current and previous study Pathologic findings in current and previous studies Comparison of histopathologic findings in the current and previous study Among all the appendectomy cases reviewed during the study period, 770 (52.5%) were histologically confirmed as AA (Table  2 ), comprising 428 males and 342 females (male-to-female ratio of 1.25:1). Perforation or rupture was most frequently observed in the 10–19 years age group (26.6% of males and 26.0% of females), followed by the 20–29 years age group. The incidence of perforation decreased with increasing age, with only 1.4% of males and 0.9% of females aged 70 years or older affected. Overall, 17.4% of the confirmed AA patients presented evidence of perforation (Table  3 ). A total of 112 patients (7.6%) had no histopathological evidence of appendiceal inflammation, indicating a negative appendectomy. These included 59 males and 53 females, with the highest proportion seen in children under 10 years of age. A greater percentage of female subjects in the active reproductive age group had a normal appendix histologic diagnosis (20–29 years, 17% versus 4.5%, and 30–39 years, 17% versus 3.4%) (Table  4 ). Table 3 Subjects with acute appendicitis Age group (Years) Male ( n  = 428) Female ( n  = 342) Total Number with Perforation/rupture  < 10 75(17.5) 59(17.3) 134(17.4) 43(20.9) 10–19 114(26.6) 89(26.0)  203(26.4) 59(28.6) 20–29 88(20.6) 100(29.2) 188(24.4) 37(18.0) 30–39 80(18.7) 49(14.3) 129(16.8)  29(14.1) 40–49 38(8.9) 20(5.8) 58(7.5) 13(6.3) 50–59 21(4.9) 15(4.4) 36(4,7)  12(5.8) 60–69 6(1.4) 7(2.0) 13(1.7) 9(4.4)  ≥ 70 6(1.4) 3(0.9)  9(1.2) 4(1.9) Table 4 Subjects with normal histology Age group (Years) Male ( n  = 59) Female ( n  = 53) Total  < 10 24(40.7) 10(18.9) 34(30.4) 10–19 3(5.1) 2(3.8) 5(4.5) 20–29 5(8.5) 13(17.0) 18(16.1) 30–39 2(3.4) 9(17.0) 11(9.8) 40–49 9(15.9) 7(13.2) 16(14.3) 50–59 9(15.3) 3(5.7) 12(10.7) 60–69 5(8.5) 4(7.5) 9(8.0)  ≥ 70 2(3.4) 5(9.4) 7(6.4) Subjects with acute appendicitis Subjects with normal histology Among the 770 patients with histologically confirmed AA, the majority were in the 10–19 years (26.4%) and 20–29 years (24.4%) age groups, followed by the 30–39 years (16.8%) age group. The incidence of cases decreased with increasing age, with only 1.2% of cases occurring in patients aged 70 years or older. Males accounted for a slightly greater proportion of confirmed cases (55.6%) than females (44.4%). There was a relatively greater burden of AA in children under 10 years of age (17.4%) (Table  5 ). Table 5 Age and sex distributions of acute appendicitis patients in current and previous studies Present study Previous study Age group (Years)  < 10 134(17.4) 10(5.3) 10–19 203(26.4) 46(24.6) 20–29 188(24.4) 54(28.9) 30–39 129(16.8) 41(21.9) 40–49 58(7.5) 14(21.9) 50–59 36(4.7) 8(4.3) 60–69 13(1.7) 0(0.0)  ≥ 70 9(1.2) 1(0.5) Sex Male 428(55.6) 123(65.8) Female 342(44.4) 64(34.2) Age and sex distributions of acute appendicitis patients in current and previous studies After AA (Fig.  3 ), Lymphoid hyperplasia was the next most common condition, affecting 29.4% of the total population, with a greater prevalence in females (34.7%) than in males (24.4%). Extra-appendiceal peritonitis was observed in 3.5% of the patients, which was slightly more common in males (3.8%) than in females (3.2%). Granulomatous inflammation (Fig.  4 ) was less common, occurring in 0.8% of the patients. Other notable findings include fibrous obliteration (2.6%), aganglionosis, endometriosis, and neoplasms (1.8%). Notably, females presented a greater percentage of neoplasms (2.5%) than males did (1.2%) (Fig.  5 ). There were a few patients with no pathological diagnosis, representing a negative appendectomy rate (NAR) of 7.6%. (Table  6 ). Fig. 3 Medium power photomicrograph showing Acute Appendicitis (H&E, × 100) and polymorphs extension to the serosa [inset, H&E, × 400] Fig. 4 Low power photomicrograph showing Schistosomal Appendicitis (H&E, × 40) and calcified S.haematobium ova [inset, H&E, × 400] Fig. 5 Medium power photomicrograph showing Adenocarcinoma of the appendix (H&E, × 100), inset show tumour cells in high power [H&E, × 400] Table 6 Distribution of pathological findings in male and female appendicitis patients Male ( n  = 746) Female ( n  = 721) Total Acute appendicitis 428(57.4) 342(47.4) 770(52.5) Chronic appendicitis 11(1.5) 5(0.7) 16(1.1) Extra appendiceal peritonitis 28(3.8) 23(3.2) 51(3.5) Fibrous obliteration 19(2.5) 19(2.6) 38(2.6) Lymphoid hyperplasia 182(24.4) 250(34.7) 432(29.4) No pathological diagnosis 59(7.9) 53(7.4) 112(7.6) Others 3(0.4) 6(7.4) 9(0.6) Neoplasm 9(1.2) 18(2.5) 27(1.8) Granulomatous inflammation 7(0.9) 5(0.7) 12(0.8) Medium power photomicrograph showing Acute Appendicitis (H&E, × 100) and polymorphs extension to the serosa [inset, H&E, × 400] Low power photomicrograph showing Schistosomal Appendicitis (H&E, × 40) and calcified S.haematobium ova [inset, H&E, × 400] Medium power photomicrograph showing Adenocarcinoma of the appendix (H&E, × 100), inset show tumour cells in high power [H&E, × 400] Distribution of pathological findings in male and female appendicitis patients

The vermiform appendix, which is often overlooked, is susceptible to an array of diseases ranging from common acute appendicitis (AA) to rare congenital and neoplastic conditions, highlighting its clinical significance beyond its size [ 1 , 2 ]. Acute appendicitis is often caused by luminal obstruction from fecaliths, lymphoid hyperplasia, or adhesions. [ 3 ] Vascular compromise and increased luminal pressure can cause ischemia, ulceration, and eventual bacterial infection [ 5 ]. Varadhan et al.’s meta-analysis revealed that, despite antibiotics being an option for some uncomplicated cases, appendectomy remains the gold standard for treating AA [ 6 ]. While AA remains the leading indication for appendectomy globally, many appendiceal pathologies are only diagnosed histologically, particularly in cases where clinical signs are nonspecific or mimic other intra-abdominal conditions [ 1 , 7 ]. Previous studies have established that the burden of AA has historically been greater among Caucasian populations and in industrialized nations. However, more recent epidemiological data suggest a shifting trend, with increasing incidence rates reported in developing countries, including Nigeria [ 8 ]. The incidence in these countries is generally lower in rural communities and has significant geographic variation. [ 9 ] For example, the incidence rates of AA in Nigeria vary by region and population, ranging from 2.6 to 5.7 per 100,000, with higher rates in low-income populations (LIPs) [ 10 ]. AA accounts for 15–40% of emergency laparotomies in tertiary centers across Nigeria [ 11 ]. Appendectomy continues to be the cornerstone treatment for AA. However, accurate clinical diagnosis remains challenging and relies heavily on patient history, physical examination, and a limited range of ancillary investigations [ 11 , 12 ]. This diagnostic ambiguity increases the incidence of negative appendectomies; wherein histopathological analysis reveals a normal appendix despite clinical indications pointing toward appendicitis. Such occurrences have been documented in as many as 25% of cases, particularly in settings where advanced imaging techniques are unavailable or underutilized [ 13 , 14 ]. The inherent risks associated with surgical procedures raise critical concerns about performing appendectomies in the absence of clear pathology. However, prompt diagnosis of AA is essential, as delays can result in appendiceal perforation [ 15 ]. Negative appendectomy (NAR) rates have declined significantly over the last two decades. These rates currently average between 6 and 8% in institutions where computed tomography (CT) and diagnostic laparoscopy are standard practices [ 16 – 18 ]. Nonetheless, these imaging modalities have inherent limitations, and their availability and impact on clinical outcomes in low-resource settings remain insufficient [ 16 , 19 ]. Histopathological examination is the gold standard for confirming appendicitis and is essential in surgical pathology [ 20 , 21 ]. A study conducted by Abdulkareem et al. revealed that histological analysis verified AA in 70.3% of patients with clinically suspected cases and revealed a range of other pathological conditions, such as parasitic granulomatous inflammation, neoplastic lesions, and reactive lymphoid hyperplasia- entities that could easily evade detection without microscopic assessment. [ 22 ] Despite the lack of standardized protocols that mandate routine histopathological evaluation of all appendectomy samples, the implications of these findings highlight their critical diagnostic and clinical significance. Notably, appendices that may appear macroscopically normal during surgical procedures can still exhibit clinically pertinent microscopic anomalies [ 23 ]. Consequently, adherence to routine histopathological review ensures diagnostic precision and promotes the prompt identification of unforeseen findings that could markedly impact patient management. Given this evidence, all removed appendices should be sent for histological examination, which is the best practice in surgical care [ 24 , 25 ]. Abdulkareem et al. previously conducted an institutional review and reported that the diagnostic accuracy, perforation rates, and incidence of negative appendectomies in Lagos were consistent with global standards. The current study builds upon that foundational research. Changes in the pathology of surgically removed appendix tissue over 16 years at Lagos University Teaching Hospital were investigated, establishing temporal trends in the incidence of appendicitis to determine whether findings regarding appendiceal pathology hold over time.

This 16-year analysis revealed trends in appendiceal pathology at a tropical tertiary center, with younger demographics, reduced sex disparity, a decrease in incidence during the COVID pandemic, and fluctuating, yearly temporal trends, as well as improved diagnostic accuracy reflected by a low negative appendectomy rate. Unexpected histopathological findings, such as lymphoid hyperplasia and neoplasms, highlight the importance of routine histological examination.

Appendicectomy is a common procedure across all ages. In this study, patient ages ranged from 4 days to 94 years (mean 24.3 years). The highest incidence occurred in the 10–19 years age group (22.8%), followed closely by those under 10 years (22.6%) and the 20–29 years age group (21.1%). Previous studies, including Abdulkareem et al. (mean age of 24.2 years), reported similar trends [ 3 , 8 , 11 , 23 , 26 , 27 ]. The findings indicate that appendicitis primarily affects young adults and children, with the UK study reporting a mean age of 32 years [ 9 , 28 ]. The current study revealed a male-to-female ratio of 1.25:1 for AA, which was lower than that reported in previous data from our centre (1.86:1) but consistent with Ajani et al.'s findings (1.2:1) [ 22 , 26 ]. In contrast, Alegbeleye and Adisa reported a female predominance with a 1:1.5 ratio [ 9 ], a trend consistent with similar studies conducted in Abuja (Duduyemi et al.), Maiduguri (Ali et al.), and Canada (Blair et al.) [ 29 – 31 ]. This demographic shift could be because more female patients with atypical presentation are diagnosed with AA as a result of better diagnostic protocols and increased access to healthcare. There was a notable decrease in appendectomies and confirmed cases of AA from 2020–2023, likely due to the COVID-19 pandemic's indirect effects, such as delayed health-seeking behavior and reduced number of elective surgeries. This trend reflects a global decline in surgical volume during the pandemic, highlighting a significant shift in healthcare delivery [ 32 ]. In our retrospective study, 52.5% of the appendectomy samples were confirmed as AA, which is lower than the 62.5% reported by Abdulkareem et al., a 10% decline [ 22 ]. This difference may reflect changes in clinical practice, particularly an increase in the medical management of suspected AA cases, which could result in fewer surgical specimens being available for histological confirmation. Additionally, the years following the previous study have witnessed a substantial expansion in healthcare infrastructure in Lagos, marked by the establishment of more hospitals and pathology laboratories, both in the public and private sectors. This broader access to diagnostic facilities may have influenced the patterns of case identification and reporting. There is also a lot of self-medication/antibiotic use without a prescription arising from the fear of surgical treatment and the cost of surgery. Finally, there was a notable rise in the number of cases presenting with lymphoid hyperplasia, especially among female patients (Tables 2 and 6 ). This trend may partly explain the reduction in histologically confirmed AA, as lymphoid hyperplasia can clinically mimic appendicitis. Al-Omran et al. also reported a 5.1% decrease in the incidence of AA over eight years. Diagnostic accuracies vary globally, with reports ranging from 64.6% to 86.9% in various regions, including Africa, the Middle East, and the UK [ 9 , 11 , 21 , 29 , 33 , 34 ]. Negative appendectomy rates (NAR) not only incur unnecessary costs and risks (including anesthetics) but also vary significantly depending on imaging use, scoring systems, and definitions, which can significantly alter reported rates. This highlights the importance of a standardized definition when comparing the NAR across different studies or institutions [ 16 ]. Our NAR was 7.6%, notably lower than Abdulkareem et al.'s 12.4%, indicating improved diagnostic accuracy. Compared with male subjects, female subjects in the reproductive age groups had more normal appendix diagnoses, with the NAR decreasing from 15.6% to 7.4% in females and from 9.8% to 7.9% in males. Comparable rates are found in Nigeria, Cameroon, and Saudi Arabia globally [ 7 , 9 , 16 , 21 , 31 , 35 ], which aligns with contemporary literature, is typically 10–20% [ 36 ]. In one study, the NAR was reported to have decreased to as low as 1.7% [ 37 ]. In the UK, advancements in imaging, particularly CT scans, have significantly reduced the NAR, with one study showing a decrease from 22.09% to 7.25% [ 38 ]. While some researchers, counterintuitively, accept a higher NAR to avoid missed cases, our low rate may reflect strong surgical expertise and clinical approaches. Bag et al. highlighted the challenges in diagnosing appendicitis in young females due to overlapping symptoms and limited imaging, leading to negative appendectomies [ 36 , 39 ]. A clinical rule was developed to differentiate pelvic inflammatory disease from acute appendicitis in women of childbearing age, achieving 99% sensitivity [ 40 ] The Alvarado score (AS) and Pediatric Appendicitis score (PAS) are established diagnostic tools, with the AS being validated for adults and showing high sensitivity at a lower cutoff. Nevertheless, it should not be the sole basis for management decisions [ 12 , 14 , 41 ]. Others have advocated improved access to diagnostic tools (ultrasound and CT scans) and minimally invasive procedures (laparoscopy), especially for females [ 11 , 16 , 36 , 42 ]. Despite advancements in imaging techniques, Flum et al. reported a 1% annual increase in the misdiagnosis of appendicitis among women of reproductive age [ 43 ]. Ma et al. reported that preoperative imaging did not significantly reduce NAR or perforation rates, emphasizing the importance of thorough physical examinations [ 7 ]. Although imaging helps reduce unnecessary appendectomies, it does not necessarily improve the diagnosis of other appendiceal problems [ 16 , 42 ] A balanced approach is key. Combining clinical judgment with imaging and striving for more efficient diagnostic strategies are important. Over the study period, the percentage of children under 10 years of age with AA increased, increasing from 5.3% to 17.4%. There were 134 children with a male-to-female ratio of 1.27:1. Among these children, 43 (20.9%) had perforation, and 30.4% presented with a normal appendix. This is quite high compared with results from other studies. A one-year retrospective study reported a NAR value of 11.3% in children. [ 44 ] Diagnosing appendicitis in children remains challenging due to ambiguous clinical presentations, necessitating careful assessment and observation before surgical intervention [ 13 , 44 ]. In our study, 17.4% of the histologically confirmed AA cases presented perforation, which was lower than the 30.5% reported in a previous study at our center. [ 22 ] The highest perforation rate of 28.6% occurred in the 10–19-year age group, which is consistent with the findings of Yasmin et al. and Al-Omran et al. [ 8 , 29 ]. Similarly, Chamisa's study reported a perforation rate of 34.0%, highlighting comparable trends in disease progression. These findings suggest delayed hospital presentation, especially in pediatric patients, despite lower rates reported in other studies [ 25 , 30 ]. Marudanayagam et al. reported a perforation rate of 13.9% in the UK, which was particularly high in patients aged 70 years and above [ 38 ]. In contrast, our study revealed a reduction from 28.6% in adolescents to under 2% in older patients, highlighting the impact of healthcare access and management strategies [ 25 ]. These findings suggest that age-related variations in the immune response and disease progression, alongside more cautious management strategies for elderly patients, may contribute to these differences. In this study, AA was the primary diagnosis at 52.5%, notably lower than Abdulkareem et al.'s findings of 62.5%, with a male predominance of 55.6% versus 65.8%. This finding reinforces the persistent trend in gender distribution observed under these conditions. [ 22 ]. Lymphoid hyperplasia was the second most prevalent finding in our cohort, occurring in 29.4% of the specimens. This figure is significantly higher than the 13.1% reported by Abdulkareem et al. and the 4.4% reported by Alegbeleye and Adisa [ 9 , 22 ]. This suggests an increase in immune-mediated changes in the appendices. The female subgroup had a greater prevalence (34.7% vs. 24.4% in males), potentially due to sex-based immunological differences or overlapping gynecological issues. Fibrous obliteration, which was observed in 2.6% of our patients, represents a chronic nonspecific pathology. This incidence was not reported in an earlier study at our center but is similar to findings from Yasmin et al. (2.1%) and Yilmaz et al. (2.84%) [ 45 ] These figures may differ primarily in terms of varying histopathological diagnostic criteria or genuine differences in chronic inflammatory patterns across geographic regions. Unusual findings in appendectomy samples increased to 3.2%, compared with 2.0% earlier, and are comparable with the findings of Dincel et al. (3%), Abudu et al. (4.2%), and Alegbeleye et al. (13.1%) [ 9 , 22 , 46 , 47 ]. While Swank et al. noted rare unexpected findings, they advised continuing histopathological examinations until more reliable data were available, despite suggestions that routine checks may be unnecessary. [48]. Granulomatous inflammation was identified in 0.8% of the patients, which is comparable to the findings of Abdulkareem et al. (1%) and other studies in Nigeria [ 22 , 28 , 35 ]. This included 4 tuberculosis and 6 schistosomiasis cases, which were consistent with the regional data. A study in Saudi Arabia revealed a greater incidence of schistosomiasis in Egyptian males (15.6%) than in other groups [ 29 ]. This aligns with the high incidence of schistosomiasis in Egypt. In contrast, Western cohorts reported Crohn’s disease and Yersinia as primary causes [ 49 , 50 ]. Some studies have questioned the prevalence of Crohn’s disease, suggesting that Yersinia may mimic its histological and clinical features. [ 15 , 51 , 52 ] It is important to consider other causes of granulomatous appendicitis before diagnosing Crohn’s disease [ 5 ]. Three cases (0.4%) of appendiceal endometriosis were observed, including one from suspected AA and two incidental findings during gynecological procedures. (ovariectomy and myomectomy). Appendiceal endometriosis is a rare condition. [ 53 ] In a categorized systematic review across 10 studies, Allahqoli et al. reported that appendiceal endometriosis presenting as AA had an overall prevalence of 2.7% (ranging from 0.3- 23%). [ 54 ] The diagnosis of appendiceal endometriosis is challenging, often requiring histopathological confirmation postoperatively, as preoperative imaging is frequently inconclusive. Neoplasms were identified in 1.8% of our patients, with a higher incidence among females (2.5%) than among males (1.2%). This finding exceeds the 1.1% reported by Abdulkareem et al. and the following rates: Omiyale et al. (1.7%), Yasmin et al. (0.27%), Hof et al. (0.47%), and Marudanayagam et al. (0.6%) [ 28 , 29 , 38 ]. A systematic review revealed that the incidence of appendiceal tumors in 1% of appendectomies increased to 10–29%, with an increase in the incidence of inflammatory masses, supporting the use of interval appendectomy for early detection and improved outcomes [ 51 ]. There were 3 premalignant lesions (flat adenomas and tubulo-villous adenomatous polyps with high-grade dysplasia). The malignant neoplasms identified in our study included lymphomas (2 cases), carcinoid tumors (1 case), low-grade appendiceal neoplasms (1 case), carcinomas (2 primary and 15 metastatic cases) and mucocele (1 case). The two lymphoma cases were observed in a 7-year-old male and a 49-year-old female. Appendiceal lymphomas are essentially rare [ 55 ]. Lymphomas represent 1–4% of gastrointestinal malignancies, with appendiceal lymphomas being exceedingly rare [ 56 , 57 ]. A review of 46 cases by Pasquale et al. revealed an average age of 25.7 years [ 58 ]. Our patients’ ages seem to support the variability in the age of presentation and suggest that appendiceal lymphomas might not be restricted to a specific age group. Mucocele, an uncommon finding (20-year-old female, 0.1%), is defined as a dilated appendix filled with mucin and accounts for 0.2–0.7% of appendiceal neoplasms. Mucinous cystadenocarcinoma, which is more prevalent in females, typically presents between the ages of 62 and 66 years [ 59 , 60 ]. Pseudomyxoma peritonei (PMP), a severe complication associated with appendiceal neoplasms, significantly worsens prognosis and may result from perforation of a malignant appendix. One patient, a 65-year-old woman, underwent an incidental appendectomy post-hysterectomy. Additionally, Appendiceal Carcinoid Tumors (ACTs) can mimic acute appendicitis, with 36% of reported gastrointestinal carcinoids located in the appendix [ 61 ]. The literature generally shows a female predominance [ 62 ]. The prognosis for ACT is generally favorable, particularly for tumors < 1 cm, necessitating screening for colorectal carcinoma due to elevated incidence rates [ 62 ]. The submission of appendectomy samples for histopathological evaluation lacks universal consensus, yet many studies advocate for routine examination owing to its benefits. Abdulkareem et al. emphasized that selective histology based on gross appearance risks overlooking significant diagnoses such as neoplasms, chronic infections, endometriosis, and inflammatory bowel disease. While Matthyssens et al. argue for histopathological assessment only in cases of macroscopic concern, evidence indicates an increase in atypical findings, including more than 50% of appendiceal tumors detected through pathology. The decision should reflect clinical judgment and institutional protocols, as routine examination enhances early diagnosis and management, improving patient outcomes and avoiding complications [ 7 – 9 , 22 ]. The unicentric and retrospective design of this study limits generalizability, as the data are derived from a single urban hospital. Over time, several other pathology laboratories have been established in the same geographic vicinity, which means that our patient population is more hospital-based than population-based compared with the baseline previous study. The lack of data on environmental, dietary, and sociopsychological factors hinders the generation of etiological insights. Further prospective research in a larger multicenter setting with broader data collection will strengthen these findings.

This retrospective, cohort, descriptive study was conducted on appendectomy specimens received by the department from January 2008 to December 2023. Two authors independently extracted data from the departmental electronic database, including sociodemographic information (patient age and sex) and clinical and histopathological diagnoses. The study encompasses all emergency, incidental, and interval appendectomies performed on patients, irrespective of age or sex, at Lagos University Teaching Hospital (LUTH), Nigeria. The exclusion criteria for patients were incomplete demographic data/incomplete medical records, or missing histopathology reports. This is an audit-based extension study; therefore, all records of appendectomy samples from appendectomies conducted at our hospital over 16 years that met the above-stated criteria. Histopathological examinations were performed in the Department of Anatomic and Molecular Pathology, LUTH. Histopathological examinations at LUTH involved formalin fixation, macroscopic assessment, and paraffin embedding of the appendectomy samples. Sections were stained with hematoxylin and eosin and then examined microscopically to confirm the presence of appendicitis or identify alternative diagnoses. Ancillary stains, such as the Gram, Ziehl–Neelsen, and silver methenamine stains, are used in unusual cases to detect Actinomyces, acid-fast bacilli, or fungi, ensuring a comprehensive pathological evaluation. The data were checked, coded, entered, and analyzed via SPSS software (IBM SPSS Statistics Version 24; SPSS Inc., Chicago, IL, USA), and the results are presented in tables and figures.

Supplementary Material 1. Supplementary Material 1.