THE SURGICAL PATHOLOGY OF THE VERMIFORM APPENDIX IN NIGERIANS: A REVIEW OF THE HISTOPATHOLOGICAL FINDINGS IN APPENDECTOMY SPECIMENS

Abstract
Background: The vermiform appendix is a cause of significant morbidity
and at times mortality, and a frequent surgical specimen, not only because
most surgeons feel it is a vestigial but potentially troublesome organ that
should be extirpated even when ‘quiet’. Although acute appendicitis is the
most common lesion diagnosed in appendix specimens, it is clear that there
is more to appendiceal disease than acute appendicitis. A lot of authors have
published studies touching on various aspects of appendiceal disease as seen
in Nigeria but there is a dearth of literature on multi-centre studies, carried
out with a view to comparing the surgical pathology of the appendix in
different geographical zones of the country. The justification for this being
that Nigeria represents an amalgamation not only of diverse ethnic
nationalities but also of diverse geographical characteristics; all of which
have a bearing on the development of appendiceal disease.
Method: We retrospectively reviewed all appendectomy specimens received
over a 7 year period, between January, 2001 and December, 2007, in 2
teaching hospitals representing the southwest and southeast zones of
Nigeria; the Obafemi Awolowo University Teaching Hospitals Complex, Ile
Ife (OAUTH) and University of Nigeria Teaching Hospital, Enugu
(UNTH). Details of data on patients’ age, sex, diagnosis at presentation and
the gross and microscopic characteristics of the specimens were retrieved
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from the archives of the morbid anatomy departments of the respective
institutions.
Results: A total of 378 and 82 appendectomy specimens in OAUTH and
UNTH respectively were seen in this study. A variety of histological lesions
were seen, comprising acute appendicitis, chronic non specific appendicitis,
granulomatous appendicitis, eosinophilic appendicitis, follicular hyperplasia,
carcinoid tumour, mucinous cystadenoma and inflammatory pseudotumour.
Acute appendicitis accounted for majority of cases diagnosed, representing
297 cases or 78.6% in OAUTH, 35 cases or 42.7% in UNTH, and 332 cases
or 72.2% overall. The negative appendectomy rate was 6.9% in OAUTH;
41.5% in UNTH and 13% overall. The mean age was 25.7 years in OAUTH
and 27.4 years in UNTH; while the peak age frequency was in the 21 – 30
years age group in both cohorts. The male to female ratio was 1.2:1 and 1:1
in OAUTH and UNTH respectively.
Conclusion: Acute appendicitis was the most frequently diagnosed lesion of
the appendix, with a peak incidence in young adults. There was significant
concordance between the gross and microscopic features of acute
appendicitis. There was also a preponderance of features associated with
severity in a majority of the cases reviewed in both centres, cutting across
gender and all age groups. Therefore clinical factors such as late presentation
rather than age or gender may be the key determinant of severity in acute
appendicitis. One major drawback experienced in this study was the lack of
consensus in diagnostic criteria for the determinants of the subsets in acute
appendicitis and diagnosis of contentious lesions such as chronic
appendicitis and follicular hyperplasia. It is hoped therefore that the findings
from this study will give impetus to the development of a minimum data set
for the reporting of appendix specimens so that inter and intra observer
variations will be minimized.

THE SURGICAL PATHOLOGY OF THE VERMIFORM APPENDIX IN NIGERIANS: A REVIEW OF THE HISTOPATHOLOGICAL FINDINGS IN APPENDECTOMY SPECIMENS