MESENCHYMAL TUMOURS OF THE GASTROINTESTINAL TRACT: THE IMPORTANCE AND USE OF IMMUNOHISTOCHEMISTRY IN CHARACTERIZING SPECIFIC TUMOUR ENTITIES.

Gabriel O. Ogun

Available online Jul 19, 2018.

[ Original ] Volume 24, Issue 2, 2015, Pages 150-154


Abstract

BACKGROUND
Mesenchymal Gastrointestinal (GI) tumours are heterogenous group of tumours. Prior to 2005, immunohistochemistry (IHC) was not
used in diagnostic pathology to characterize these tumours at our centre.
OBJECTIVES
To subclassify mesenchymal tumours in the GI tract and related locations into Gastrointestinal stromal tumour (GIST) and non-GIST
tumours using specific IHC antibody markers.
METHODS
Formalin Fixed Paraffin Embedded tumour tissue over the period 1991- 2004 were retrieved, from the files and records of the
Department of Pathology, University College Hospital, Ibadan, Nigeria. Haematoxylin and Eosin slides of such cases were reviewed.The
IHC expressions of c-Kit,CD 34,a-smooth muscle actin,desmin and S-100 were evaluated in these tumours.
RESULTS
Based on morphology and IHC staining pattern,24 of the 46 cases were identified as GIST by c-kit positivity. Nine of the cases were
smooth muscle tumours ( 4- leiomyoma and 5- leiomyosarcoma),8 cases of undifferentiated sarcomas,4 cases of desmoid and one case of
inflammatory myofibroblastic tumour.For GISTs :The male:female ratio is 1.2.The age range of the patients was 11-75 years with a mean
age of 55.1 years.Tumour size ranged from 7-32 cm with an average of 19.8cm and average mitotic count of 20 per 50 high power field.The
location of the GIST tumours were as follow- stomach- 9 cases (37.5% of the 24 GIST cases),colon and rectum -6 (25%),Abdominal cavity
(omentum/ mesentery)- 6 (25%),retroperitoneum-2(8.3%),small intestine-1 (4.2%).
CONCLUSION
The use of IHC in this study has helped to segregate and distinguish GI mesenchymal tumours into different sub-types, majority being
Gastrointestinal stromal tumours.


Keywords

Gastrointestinal tract, mesenchymal tumours, GIST, Immunohistochemistry, smooth muscle tumours, leiomyoma, leiomyosarcoma,