The vermiform appendix is a tubular structure arising from the medial wall of the caecum.[2] Reginald Fitz was the first pathologist to describe acute appendicitis and suggested appendicectomy as the treatment of choice. Acute appendicitis is a common cause of acute abdomen.[3] In spite of the recent advancement clinical diagnosis of acute appendicitis is accurate in only 60-80% of cases. Therefore, histopathological examination remains the gold standard method for the confirmation of appendicitis. [1] Luminal blockage is the main factor in acute appendicitis, usually by fecolith or lymphoid hyperplasia. However other uncommon causes include parasites and tumors.

Neoplastic lesions are rare, often unnoticed and diagnosed as an incidental finding in appendicectomy performed for other reasons. They are rarely defined intraoperatively in 0.7 to 5% of patients.[4,5] Some low-grade lesions remain undetected and in advanced stages may mimic acute appendicitis.[3]

Adenocarcinoma may present as perforated appendicitis due to excessive mucous production, metastasizing to adjacent organs. The general treatment options have wider spectrum including complete surgical excision of appendix with or without right hemicolectomy to cytoreductive surgery depending on the appendicular pathology and type of neoplasia. Hence, histopathological evaluation of appendicular lesion is very important.

AIMS & OBJECTIVES

 To study spectrum of histopathologic diagnoses in all the appendectomy specimen received in view of better management and to estimate the incidence of unusual findings affecting the patients morbidity and mortality.

This is a retrospective study of 24 months in histopathology department at tertiary health care center. Total of 430 appendicectomy specimen received were assessed. Relevant clinical data along with radiological findings were retrieved. Gross findings were noted. Hematoxylin & eosin stained slides were reviewed and diagnoses proposed based on the data. Immunohistochemistry and special stained slides reviewed whenever needed.

Total 430 specimens were analyzed. 238 (55.35%) were males and 192(44.65%) were females. 11 to 20 years is the most common age group.

Table 1: Distribution of appendicular pathologies

Among all cases 425 (98.83%) cases were non-neoplastic, 5 (1.17%) cases were neoplastic origin.

Table 2: Distribution of neoplastic appendicular pathologies

Table 3: Histopathological diagnosis for 430 appendicular cases

Historically, the most popular theory regarding the pathogenesis of acute "nonspecific appendicitis has been that of obstruction of the appendiceal lumen. Advocates of this theory argue that obstruction (by fecolith, adhesions, tumor, lymphoid hyperplasia, etc.) leads to increased intraluminal pressure and that the resulting secretions under pressure impair the resistance of the mucosa to invasion by microorganisms.[2]

Controversy persists however, and detractors from the obstruction theory point out that evidence of obstruction is found in only a minority of appendices resected for acute appendicitis. Other theories include compromise of the extramural vascular supply, mucosal ulceration (possibly secondary to viral infection) with superimposed bacterial infection, and low-fiber diets resulting in retention of stool and resultant susceptibility to infection. It is fair to say that no single theory explains all cases of acute nonspecific appendicitis and that multiple factors may lead to mucosal ulceration and invasion of the wall by enteric bacteria.{2}

Table 4: Comparison with other studies

Table 5: Comparison of Neoplastic Lesions

The current study was done for a period of 24 months and shows the histopathological findings of 430 appendicectomy specimens received in the Department of Pathology at tertiary health care center.

Acute appendicitis is the most common inflammatory pathology of appendix and affect especially young people.[9,10] In current study maximum number of patients who underwent appendicectomy diagnosed as acute appendicitis belonged to the age group of 11-20 years, which is concordant with the study done by AP Punnoose et al.[6] which also showed that most of the appendicectomies (60%) were done in the age group of 11-30 yrs.

In terms of gender variability lifetime risk of acute appendicitis is 8.6% in females and 6.7% in males.[11] In current study number of appendicectomies performed were more in males (55%) as compared to females (45%) which were concordant with findings by AP Punnoose et al.[6] who studied 576 cases of appendicectomies , in which, 338 (58.7%) were males and 238 (41.3%) were females.

Amongst 430 appendicectomy specimens, 425 (98.83%) were found to be non- neoplastic lesions and only 05 (1.17%) cases were diagnosed as neoplastic lesions. In a study by AP Punnoose et al.[6] it was reported that 99% of appendicectomy cases were non-neoplastic lesions and 1% were neoplastic which was concordant with our study.

In the current study, acute appendicitis accounted for the most common histopathological lesion for which appendicectomy was done and was seen in 191 cases (44.42%) of patients. These findings are concordant with the study done by R. Sujatha et al.[1] in which acute appendicitis accounted for 46.5%.[1]

Acute suppurative appendicitis constituted for second most common finding accounting for 109 cases (25.35%) which are discordant with any of the studies. Chronic appendicitis constituted 71 cases (16.51%) which are concordant with study done by AP Punoose et al. accounting for 10.06%.[6] Perforated appendicitis constituted 38 cases (8.84%), concordant with Elfaedy et al. study which is 5.1%.[8]

This study included 03 cases (0.7%) of eosinophilic appendicitis. Eosinophilic appendicitis is characterized by lack of neutrophils, there is eosinophilic infiltrate in muscularis layer. Eosinophilic appendicitis is reported in study by R. Sujatha et al.[1] and AP Punoosse et al.[6]The findings of tubercular appendicitis were reported in 03 (0.7%) cases, similar results are seen in AP Punoose et al. study (0.69%).[6]

Other important incidental findings diagnosed were 2 cases of adenocarcinoma which accounted for 0.47% of total cases, concordant with the study done by Meryem et al.{7} 3 case of well differentiated neuroendocrine tumor accounting for 0.7 % similar results are seen in R. Sujatha et al. study.[1] In mucinous neoplasm, especially adenocarcinoma appendix may perforate due to excessive mucin production presenting as perforated appendicitis, spreading to adjacent organs.

 In summary, present study shows most common age group of 11-20 years, with male to female ratio of 1.2:1. Most common non neoplastic histopathology diagnosis of Acute appendicitis. Neoplastic lesions accounting for 1.17% Neuroendocrine tumor and Adenocarcinoma.

Our study showed appendicectomy cases, in which diagnosis of tubercular appendicitis, carcinoid and adenocarcinoma of appendix was more alarming for prognosis and management, which were missed clinically or intraoperatively.

Present study concludes that important incidental diagnoses and the increasing trend of malignancies globally, mandates for routine histopathological examinations in all appendicectomy specimens.

1. Sujatha R, Anushree CN, Singh N. Histopathological spectrum of appendicectomy specimens- a prospective study. Indian J Pathol Oncol. 2017 Oct;4(4):638-42.
2. Goldblum JR, Lamps LW, McKenny JK, MyersJL. Rosai and ackerman’s surgical pathology 11th edition. Elsevier 2017.
3. Constantin, Marian, Livia Petrescu, Cristina Mătanie, Corneliu Ovidiu Vrancianu, Adelina-Gabriela Niculescu, Octavian Andronic, and Alexandra Bolocan. 2023. "The Vermiform Appendix and Its Pathologies" Cancers 15, no. 15: 3872.
4. Young S, Sueda SK, Hotta M, et al. Surgical management of appendiceal mucinous neoplasm: Is appendectomy sufficient?. J Surg Oncol. 2020;122:1173
5. Deans GT, Spence RA. Neoplastic lesions of the appendix. Br J Surg. 1995;82:299-306.
6. Punnoose AP, Joseph E, Joseph D, et al. Histopathological evaluation of lesions of appendix - a cross sectional study. J Evid Based Med Healthc 2021;8(34):3187- 3192. DOI: 10.18410/jebmh/2021/580
7. Maryam Adam Mohamed Ali, Sameer Ahmed A.H Ansari, Khalid Al Sindi et.al. Routine histopathological examination of appendix: the practice that cannot be ignored. Int J Health Sci Res. 2021; 11(4): 48-54. DOI: https://doi.org/10.52403/ ijhsr.20210406
8. Elfaedy O, Benkhadoura M, Elshaikhy A, et al. Impact of routine histopathological examination of appendectomy specimens on patient management: a study of 4012 appendectomy specimens. Turk J Surg 2019;35(3):196- 201
9. Deshmukh, S.; Verde, F.; Johnson, P.T.; Fishman, E.K.; Macura, K.J. Anatomical variants and pathologies of the vermix. Emerg. Radiol. 2014, 21, 543–552.
10. Nikolaidis, P.; Hwang, C.M.; Miller, F.H.; Papanicolaou, N. The nonvisualized appendix: Incidence of acute appendicitis when secondary inflammatory changes are absent. AJR Am. J. Roentgenol. 2004, 183, 889–892.
11. Krzyzak, M.; Mulrooney, S.M. Acute appendicitis review: Background, epidemiology, diagnosis, and treatment. Cureus 2020, 12, e8562.