| Abstract|| |
Background: Gastrointestinal (GI) smooth muscle tumors are a group of intramural GI tumors formerly known as leiomyoma and leiomyosarcoma. This retrospective study was made to review our experience in surgical management of GI smooth muscle tumors. Methods: The clinical records for patients with GI smooth muscle tumors during 1993-1999 were reviewed. Results: Ten tumors were located in stomach. Abdominal pain was the main presenting symptom followed by GI bleeding. The preoperative diagnosis was made by enhanced computerized tomography (CT) on eleven patients out of thirteen, while upper GI endoscopy with biopsy identified six tumors out of thirteen patients had the test. Tumors were treated by conservative excision in four and radical excision in fourteen. Histology was leiomyoma in six patients (with mitotic figures <4 per 10 high power field) and leiomyosarcoma was found in twelve patients (with mitotic figures >4 per 10 high power field). Median follow-up was 4 years. There was one recurrence for leiomyoma (size: 6cm). All patients with leiomyosarcoma presented later with metastasis and died. Conclusion: Size and mitotic activity of tumors are the main determinant factors. Enhanced CT remains the proper diagnostic tool.
Keywords: Gastrointestinal (GI), smooth muscle tumors, leiomyomas, leiomyosarcomas.
|How to cite this article:|
Al Salamah SM, El Keyali AY. Management of gastrointestinal smooth muscle tumors: Seven years experience of a teaching hospital in Saudi Arabia. Saudi J Gastroenterol 2000;6:153-6
|How to cite this URL:|
Al Salamah SM, El Keyali AY. Management of gastrointestinal smooth muscle tumors: Seven years experience of a teaching hospital in Saudi Arabia. Saudi J Gastroenterol [serial online] 2000 [cited 2020 Feb 27];6:153-6. Available from: http://www.saudijgastro.com/text.asp?2000/6/3/153/33477
Smooth muscle tumors of GI tract are uncommon. They are classified as benign leiomyoma, malignant leiomyosarcoma or low malignant potential  . The criteria for malignancy are so unreliable that sometimes only in retrospect can the tumor be called benign or malignant based on its behavior years subsequent to resection , .
Patients with these tumors may remain asymptomatic or manifest symptoms referable to tumor size, growth pattern and location. GI bleeding manifested by haematemesis, melena or iron deficiency anaemia has been the most frequent presenting symptom  .
While size and mitotic activity of these tumors have been the most important determinant factors, surgical resection remain the only method of managemen  .
The present retrospective analysis was undertaken therefore to analyze our experience with GI smooth muscle tumors with particular reference to their clinical presentation, diagnosis, treatment and prognosis.
| Patients and Methods|| |
We retrospectively reviewed the clinical records of 18 patients at our hospital during 1993 -1999 with diagnosis of GI smooth muscle tumors.
Data obtained patient sex, age, symptoms and physical findings leading to work-up, preoperative diagnostic evaluation and operative findings such as location and morphology of the tumor. Pathology reports and treatment were reviewed as well. Further follow-up information was obtained in some of them. The distinction between leiomyoma and leiomyosarcoma was based on the mitotic rate. Leiomyoma was considered, if mitotic rate was 4 or less per 10 high power field. High-grade leiomyosarcoma was diagnosed when mitotic rate is 10 or more per 10 high-power fields, while lowgrade leiomyosarcoma, mitotic rate was between 5-9 per 10 high-power fields.
| Results|| |
Eighteen patients with GI stromal tumors were seen during the seven years period. The median age at time of diagnosis was 54 years (range 28-76 years) with a male predominance (2:1).
As illustrated in [Table - 1], the majority of tumors (55%) were located in the stomach. Other site in order of decreasing frequency, were the small intestine (39%) and oesophagus (6%). Seven patients with gastric tumors and five patients with small bowel tumors were presented with epigastric abdominal pain. Upper GI bleeding was the presentation in six patients with gastric tumors, while mechanical obstruction was the presentation in two small bowel tumors. One oesophageal tumor and two gastric tumors were primarily causing dysphagia. A considerable weight loss was seen in ten patients. One small bowel tumor presented with peritonitis.
Upper GI endoscopy and biopsy identified five gastric lesions out of ten who had the test and one oesophageal lesion. Contrast studies diagnosed one small bowel lesion out of three patients who had the test. CT was diagnostic in seven out of eight gastric lesions [Figure - 1],[Figure - 2] and in three out of four small bowel tumors in patients who were evaluated.
Three tumors in small bowel were diagnosed intra-operatively [Figure - 3] two were presented with intestinal obstruction and one with peritonitis (perforated tumor).
According to histopathology results, six had leiomyoma (five in stomach and one small bowel), three low-grade leiomyosarcoma (small bowel lesions) and nine high-grade leiomyosarcoma (five in stomach, three small bowel and one oesophagus).
In general, GI leiomyosarcoma were larger than leiomyoma. The average diameter of benign smooth muscle tumor was 4.5cm (range 3-6cm) while that of malignant tumor was 11.4cm (range 6-17cm).
All patients underwent tumor excision [Table - 2]. Excision with margin greater than 5cm considered as radical excision and excision with margins less than 4cm was considered as conservative local excision. Four leiomyomas were treated by conservative excision while other two leiomyomas were treated by radical excision because of its location. Eleven low and high-grade leiomyosarcomas were treated with radical excision while one low-grade leiomyosarcoma had conservative resection.
Follow-up was available for thirteen patients (72%). Median follow-up was four years with minimum follow was six months. Only one of the five patients followed up for 1-5 years had recurrence. Size of tumor that recurred was 6cm who died two years after excision of the recurrence. All eight patients with leiomyosarcomas had local and hepatic metastasis. Six of them died within two years after excision of the tumor.
| Discussion|| |
Smooth muscle tumors including leiomyomas and leiomyosarcomas are relatively uncommon. With regard to the position of the neoplasm, three growth patterns have been identified: intramural, extramural or bi-directional. In small intestine the most common type is extramural followed by intramural  . Usually it is quite difficult to determine preoperatively whether the lesion is malignant or not as the tumor is sub-mucosal  .
Patients with smooth muscle tumors of GI tract may be entirely asymptomatic or may manifest symptoms referable to tumor size, growth patterns and location. Our review is similar to Bruneton's series  , in which the main clinical presentation was abdominal pain, there was no significant difference in clinical presentation between leiomyomas and leiomyosarcomas except that a palpable mass was encountered in the majority of leiomyosarcomas (eight), presumably due to their larger size.
Our report confirms the distribution by site of GI smooth muscle tumors as reported in other series with the stomach is the most common site , . Preoperative detection of these GI tumors is very difficult. However, CT can assist in determining the benign or malignant nature of some lesions ,, . CT appearance both before and after contrast enhancement suggests that the malignant lesions are larger, less uniform in shape and non-homogenous , . Contrast studies may define a well-circumscribed luminal defect. Endoscopy may show ulcerated or raised mucosa overlying a tumor mass .
In our series CT Scan was diagnostic in eleven (84%) out of thirteen who had this test while upper GI endoscopy with biopsy diagnosed six out of eleven who had the test. Histologically the distinction between benign and malignant tumors is difficult to make and the classification of malignancy is often unreliable , . However two of the strongest pathologic predictors of malignant behavior are size (general >5cm) and mitotic count (generally >5 mitoses per 10 high power field) ,.
Surgical excision is the only treatment for smooth muscle tumors as they are usually radio-resistant and insensitive to chemotherapeutic agents. Conservative resection for leiomyoma is suggested in literature by Morgan et al who reported 103 cases of leiomyoma and found no recurrence with complete tumor resection regardless the width of resection margin  . Also, Evans found no statistical relationship between the extent of surgical excision and survival . Local recurrence rates have been reported to be high for malignant tumors  .
In our series, eight patients who had follow-up with leiomyosarcoma, had local recurrence and liver metastasis and six of them died; five with leiomyoma who had follow-up, there was only one local recurrence.
Liver and peritoneum is the most common site of metastasis. Metastasis to local lymph nodes doesn't occur. Thus there is no need for routine regional lymph nodes dissection ,, .
In conclusion, enhanced CT scan becomes the most accurate test. The size and mitotic activity of these tumors are the main determinant factors. Finally there is a widespread agreement that wide resection of the lesion is the appropriate treatment for patient with smooth muscle tumors of the GI tract.
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Saleh M Al Salamah
Consultant General Surgeon, University Unit, Riyadh Medical Complex, P.O. Box 31168, Riyadh 11497
Source of Support: None, Conflict of Interest: None
[Figure - 1], [Figure - 2], [Figure - 3]
[Table - 1], [Table - 2]