Value of enhanced computed tomography in differentiating small mesenchymal tumours of the gastrointestinal from smooth muscle tumours

BACKGROUND

Computed tomography (CT) technology has been gradually used in the differentiation of small mesenchymal tumors of the stomach and intestines from smooth muscle tumours.

AIM

To explore the value of enhanced CT in the differentiation of small mesenchymal tumors of the stomach and intestines from smooth muscle tumours.

METHODS

Clinical data of patients with gastric mesenchymal or gastric smooth muscle tumours who were treated in our hospital from May 2018 to April 2023 were retrospectively analysed. Patients were divided into the gastric mesenchymal tumor group and the gastric smooth muscle tumor group respectively (n = 50 cases per group). Clinical data of 50 healthy volunteers who received physical examinations in our hospital during the same period were selected and included in the control group. Serum levels of carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), carbohydrate antigen 19-9 (CA19-9), CA-125 and cytokeratin 19 fragment antigen 21-1 were compared among the three groups. The value of CEA and CA19-9 in the identification of gastric mesenchymal tumours was analysed using the receiver operating characteristic (ROC) curve. The Kappa statistic was used to analyse the consistency of the combined CEA and CA19-9 test in identifying gastric mesenchymal tumours.

RESULTS

CEA levels varied among the three groups in the following order: The gastric mesenchymal tumour group > the control group > the gastric smooth muscle tumour group. CA19-9 levels varied among the three groups in the following order: The gastric mesenchymal group > the gastric smooth muscle group > the control group, the difference was statistically significant (P < 0.05). ROC analysis showed that the area under the curve of CEA and CA19-9 was 0. 879 and 0. 782, respectively.

CONCLUSION

Enhanced CT has shown value in differentiating small mesenchymal tumors of the stomach and intestines from smooth muscle tumors.

Epstein-Barr Virus-Associated Smooth Muscle Tumour: A Case Series with a Significant Proportion of Tumours Showing Proclivity for Cutaneous Soft Tissues

Background

Epstein-Barr virus-associated smooth muscle tumours (EBV-SMTs) are rare neoplasms of uncertain biological potential. They are seen in the setting of immune suppression from a variety of causes, including HIV infection and post-transplant immunosuppression. Most of the literature pertaining to these neoplasms comprises case reports and small case series, with a dearth of documented cases from South Africa.

Objective

To expand on the literature of these rare neoplasms in the South African context, with an emphasis on a subset showing a predilection for the cutaneous soft tissues.

Method

Twenty-one EBV-SMTs from 19 consecutive patients were retrieved from the archives of the Division of Anatomical Pathology in the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, and the National Health Laboratory Service. Clinical and pathological characteristics of each case were recorded, including patient age, tumour site, H&E morphology, immunophenotypic features and the tumoural EBV status.

Results

The patients' ages ranged from 12 to 63 years, with a mean of 36 years. Thirteen (68%) of the patients in whom the HIV status was known were HIV-positive. Two of the 19 patients each had 2 tumours, thus accounting for the total of 21 neoplasms studied. Although 12 of the 21 tumours (57.1%) were from a variety of visceral organs, 9 (42.9%) originated in the dermis and superficial subcutaneous tissues, making the cutaneous soft tissues the most commonly affected site. Morphologically, all of the neoplasms were characterised by fascicles of myoid cells, admixed rounder tumour cells, scattered intratumoural lymphocytes and variable immunohistochemical staining with markers of smooth muscle differentiation. All 21 neoplasms were proven to harbour EBV DNA.

Conclusion

A significant proportion of EBV-SMTs may present in the cutaneous soft tissues. This neoplasm should, therefore, be included in the histopathological differential diagnosis of any cutaneous or superficial subcutaneous spindle cell tumour, especially in patients with a history of underlying immune suppression. Accurate diagnosis thereof and its distinction from other spindle cell neoplasms is important in view of management implications and the potential for multicentricity in some patients.