Gastric leiomyomas are rare benign tumors of the stomach that have an asymptomatic course in most cases, but anemia, bleeding, and gastric ulceration may be seen. They share numerous characteristics with gastrointestinal stromal tumors that can be malignant, which is why the diagnosis includes endoscopy, biopsy, and immunohistochemical staining. Treatment depends on the tumor diameter, but excision of the tumor is usually recommended, especially in symptomatic patients.
As mentioned, the vast majority of leiomyomas are asymptomatic, but the most common symptoms are anemia due to gastric ulceration and subsequent hemorrhage, together with pain that is nonspecific and occasional dyspepsia . Dysphagia, esophageal reflux, and retrosternal burning are scarcely reported. The tumor has a very long growth period and only tumors with a very large diameter are shown to cause symptoms.
To make the diagnosis of gastric leiomyoma, several steps in the workup should be made. Initial evaluation can be conducted through various imaging studies, such as computed tomography or abdominal ultrasonography that may reveal the presence of a subepithelial or intraluminal mass . Virtually all cases of upper gastrointestinal bleeding, however, should be evaluated through endoscopy, a minimally invasive procedure that provides a direct view into the esophageal and gastric mucosa . Because tumor differentiation cannot be made by macroscopic appearance, biopsy, and subsequent immunohistochemical staining is imperative in defining the type of the tumor. Leiomyomas have very similar microscopic characteristics compared to GISTs, but the vital distinguishing feature on immunohistochemistry is negative staining for c-Kit, a proto-oncogene that gives GISTs their malignant potential . Rare cases, however, have confirmed positive c-KIT staining in gastric leiomyoma , which is why other features, such as positive desmin and α-smooth muscle actin staining, together with negative s100 staining, are important in further differentiating the tumor. Once a definite diagnosis is made, appropriate treatment procedures may be initiated.
Before making an optimal treatment strategy, various factors have to be considered, including the tumor size, location, and presence of symptoms. Asymptomatic, smaller tumors do not require immediate surgical therapy and can be followed by periodic endoscopy examinations . On the other hand, larger tumors that are symptomatic necessitate excision. When possible, surgical excision through an endoscopic approach is favorable due to the fact that it is minimally invasive compared to laparoscopy and open surgery. One of the major limitations of endoscopic surgery is the risk of severe bleeding when leiomyomas are adjacent to the serosa and the adventitia, having in mind that they arise from the muscularis propria or the muscularis mucosae . Laparoscopic surgery provides significant benefit over open surgery due to reduced risks while being less invasive and most efficient approaches include laparoscopic wedge resection, intragastric resection, and gastrotomy with resection . In some cases, when particularly large tumors are located in tricky areas for operation, a combined approach may be necessary,
Leiomyomas of the stomach are benign, their malignant potential is minimal and adequate therapy can efficiently remove the tumor, all indicating a very good prognosis. Moreover, certain studies estimated that up to 90% of tumors remain asymptomatic throughout life , and the diagnosis can often be made incidentally.
Gastric leiomyoma stems from either the lamina muscularis mucosae when it is termed to be superficial, or it may arise from muscularis propria, in which case it is a deep tumor . The exact cause of tumor development remains unknown. In virtually all cases, this tumor appears as a small, solitary lesion and histological inspection reveals well-differentiated smooth muscles with eosinophilic cytoplasm, very scarce mitotic activity and myofibrillar absence . These features indicate that the tumor is almost exclusively benign, but the malignant transformation was reported in a few cases .
These benign tumors comprise approximately 2.5% of all gastric neoplasms, but they are one of the most common benign stomach tumors encountered . Because gastric leiomyomas are rarely encountered in practice, epidemiological data mainly rest on sporadic case reports. In fact, a crude incidence rate estimates that this tumor appears in approximately 3 per million individuals . It is somewhat more frequently seen in male individuals between 50-70 years , while ethnic predilection has not been established. The sixth decade of life is the period in which the highest incidence rates are observed, but patients of any age may be affected. The tumor may develop at any site in the stomach, but the corpus and antrum are shown to be the most common sites of occurrence .
Not much is known about the pathogenesis of gastric leiomyomas, apart from the fact that they arise as round, solitary lesions in the lamina muscularis mucosa and muscularis propria. The microscopic appearance that includes an abundance of hyperplastic smooth muscle cells with minimal mitotic activity and reduced expression of c-Kit have shown to be primary factors for its benign nature , but which mechanisms lead to is development remain unclear.
As the exact pathophysiological mechanism of development is unclear, current preventive strategies do not exist. Although wide-scale screening of elderly patients could be considered as a preventive measure, screening for this particulate tumor may not be necessary, as it causes very little harm to the patient due to its asymptomatic course and very little potential for malignant transformation.
Gastric leiomyomas are rare tumors of the stomach and comprise about 2.5% of all gastric neoplasms . These tumors originate either from the muscularis mucosae or the muscularis propria, based on which they can be classified as superficial and deep, respectively . Both macro- and microscopically, leiomyomas closely resemble gastrointestinal stromal tumors (GISTs) that develop from mesenchymal cells and have oncogenic potential. The main distinguishing characteristic is the expression of the tyrosine-protein kinase Kit or proto-oncogene gene c-Kit, a stem-cell growth factor that is present in GISTs , but not in leiomyomas, making this tumor almost universally benign. Epidemiology data is composed of scarce case reports and some rough estimates suggest that the incidence rate is approximately 3 per one million individuals . Certain studies have established that the sixth decade of life is the period in which tumor development is most common, but patients of any age may be affected . In terms of tumor localization, the corpus is a common site of occurrence, while the cardia and the antrum are reported as well  . An asymptomatic course is seen in most cases, whereas symptoms such as anemia due to mucosal ulceration and gastrointestinal hemorrhage may be seen in up to 50% of cases . To make the diagnosis, endoscopic ultrasonography (EUS) is the initial method choice that can identify the location and the extent of tissue involvement. The tumor appears as a homogenous and hypoechoic lesion with clear margins on EUS. Additional immunohistochemical staining, however, must be performed to distinguish it from GISTs. Positive staining for α-smooth muscle actin and desmin, with a negative staining s100 proteins, in addition to c-Kit, are criteria for the diagnosis of gastric leiomyoma. Treatment principles primarily depend on the size of the tumor, but complete surgical excision is the optimal treatment method. Endoscopic approach is performed, if possible because it is minimally invasive. For patients in whom the location and size of the tumor increase the chance of adverse effects, such as bleeding, a laparoscopic approach may be indicated . Gastric leiomyoma has a good prognosis, as the vast majority of these tumors are discovered incidentally and do not cause any symptoms, with a minimal potential for malignant transformation.
Gastric leiomyoma is a very rare tumor of smooth muscle cells located in the stomach and is established to occur in about 3 per one million individuals. The exact cause is not known, but it is most frequently diagnosed in elderly patients between 50-70 years of age. Although this tumor shares several characteristics with gastrointestinal stromal tumors (GISTs) that have significant potential for malignant transformation, it is considered to be universally benign, with very rare reports of progression into malignant neoplasms. It is estimated that the vast majority of individuals with this tumor are undiagnosed, as symptoms are rarely reported. However, in the case of larger tumors that cause ulceration of the gastric mucosa, anemia, bleeding, swallowing difficulties and pain may be reported. To make the diagnosis, initial imaging studies such as ultrasonography and computed tomography (CT scan) scan may identify a mass in the stomach. An endoscopic ultrasound, the diagnostic procedure of choice, includes insertion of an endoscope through the throat and into the stomach, can further distinguish between various types of tumors, but the definite diagnosis can be made after performing a biopsy. A specific method called immunohistochemistry is the ultimate diagnostic tool, identifies specific tumor molecules that can distinguish leiomyoma from other tumors, mainly GISTs. Once the diagnosis is made, treatment depends on the location and size of the tumor, as well as the severity of symptoms. The goal of treatment is to abolish symptoms, if present and remove the tumor from the stomach, which can be done by and endoscopic or laparoscopic surgery. Endoscopic surgery is the least invasive form of surgical therapy, but it may not always be carried out, as these tumors carry a high risk of bleeding when performing this procedure in some patients. For these reasons, laparoscopy and resection of the tumor are most frequently performed. Overall, patients with this tumor have a very good prognosis, as it very rarely causes symptoms and has little a potential for malignant transformation.