Small intestinal tumors are relatively rare, accounting for approximately 5% of all gastrointestinal tumors. Due to the nonspecific symptoms associated with these tumors, diagnosis can be challenging.
Common benign tumors of the small intestine include adenomas and leiomyomas. Other types, such as lipomas, fibromas, and hemangiomas, are less frequently encountered. Malignant tumors commonly include small intestinal stromal tumors, neuroendocrine tumors, adenocarcinomas, malignant lymphomas, and leiomyosarcomas. Metastatic tumors to the small intestine are also observed in some cases.
Clinical Manifestations
The symptoms of small intestinal tumors are typically nonspecific and may include one or more of the following:
Abdominal Pain
Abdominal pain is the most common symptom and may present as dull or distending pain. In cases of intestinal obstruction, the pain tends to be severe.
Intestinal Bleeding
Bleeding is often intermittent, manifesting as melena or hematochezia, though massive bleeding may occur in some cases. Chronic anemia can result from long-term occult bleeding.
Intestinal Obstruction
The most frequent cause of acute intestinal obstruction is secondary intussusception. Tumor-induced intestinal lumen narrowing and compression of adjacent bowel loops can also lead to obstruction. Intestinal volvulus may occur in some cases.
Abdominal Mass
Abdominal masses associated with small intestinal tumors often exhibit significant mobility and are typically located in indeterminate positions.
Intestinal Perforation
Intestinal perforation is more commonly seen in malignant small intestinal tumors. Acute perforations lead to peritonitis, whereas chronic perforations may result in enteric fistulas.
Carcinoid Syndrome
Carcinoid syndrome is typically observed in patients with neuroendocrine tumors accompanied by liver metastases. The most common symptoms are diarrhea and facial flushing.
Diagnosis
Small intestinal tumors are often insidious in onset and characterized by nonspecific clinical symptoms. The absence of early physical signs or effective diagnostic methods can lead to delayed diagnosis. Patients presenting with one or more of the aforementioned symptoms should be evaluated for the possibility of small intestinal tumors through further diagnostic testing.
Imaging studies, including abdominal CT and CT enterography (CTE), are useful for diagnosing small intestinal tumors and for assessing their extent of invasion or metastasis. Small bowel air-barium imaging can help localize the tumor, while angiography can assist in pinpointing the site of tumor-related bleeding. MRI or PET-CT may be performed when necessary.
Diagnostic endoscopic procedures, including duodenoscopy, enteroscopy, and capsule endoscopy, can improve the accuracy of diagnosis.
In certain cases, laparoscopy or exploratory laparotomy may be utilized for definitive evaluation.
Treatment
The treatment of small intestinal tumors depends largely on the type, location, and stage of the tumor.
Small or pedunculated benign tumors may be excised locally, including the surrounding intestinal wall tissue. Larger or locally multifocal benign tumors may require segmental intestinal resection and anastomosis. Malignant tumors often necessitate radical resection, including excision of the affected segment along with the mesentery and regional lymph nodes. Postoperative treatment, such as chemotherapy, may be indicated depending on the tumor stage.
In cases where the tumor has infiltrated surrounding tissues and become fixed, thus rendering resection unfeasible, palliative bypass surgery may be performed to alleviate obstruction.