Small bowel malignancy (SBM)

Small bowel malignancy (SBM)

Abstract:

Background: Small bowel malignancy (SBM) is a relatively rare type of cancer when compared to other gastrointestinal diseases. The most common histologic subtype is adenocarcinoma (40%), and duodenum is the most commonly involved segment. Clinically, SBM presents with vague abdominal symptoms, which, along with the inaccessibility by Endoscope and lack of proper screening tools, makes its clinical detection a diagnostic challenge. The knowledge about the clinical characteristics, treatment options, or prognosis of patients with SBA, especially in Asians, has not been described in detail in the literature.

Case presentation: This is a case report of a 27-year-old male, who presented with non-specific gastrointestinal symptoms. He had multiple visits to the hospital for these symptoms. Later, he had been diagnosed with intussusception on a CT scan and underwent surgery for this. On exploration, he had an unpassable stricture in the jejunum, 1 foot from DJ. We did resection anastomosis of the jejunum, which later turned out to be adenocarcinoma. The patient refused any further treatment, and he is free of recurrence at a 6-month follow up.

Conclusion: the adenocarcinoma of the small bowel is a rare entity, and particularly in Pakistan, the literature available is limited. SBM should be included in the differentials of patients with vague abdominal symptoms. Future studies for the evaluation of new investigations and treatment modalities should be encouraged to improve the overall outcome of the patients.

Keywords: Small bowel malignancy, Intussusception, Rarity, Intestinal obstruction. Intestinal stricture.

Introduction:

Gastrointestinal malignancy is still the primary concern of health problems in Worldwide. However, small bowel malignancy (SBM) is a relatively rare type of cancer when compared to other gastrointestinal diseases, while having glaring similarities to the said malignancies. Despite it being rare, primarily of GI origin is 3-6%, with only 1-2% of malignant1,2. Most of the time is the incidental finding on histopathology. The most common histologic subtype is adenocarcinoma (40%), and duodenum is the most commonly involved segment, followed by jejunum and ileum3,4. Clinically, SBM presents with vague abdominal symptoms, which, along with the inaccessibility by Endoscope and lack of proper screening tools, leads to an average delay of 6–10 months in diagnosis5,6. There is little known about the clinical characteristics, treatment modalities, or prognosis of patients with SBA, especially in Asians7.

In this case report, we are presenting a 27-year-old patient, who initially underwent surgery for a preliminary diagnosis of intussusception of jejunum, which later turned out to be adenocarcinoma of the jejunum.

Case presentation:

A 27-year-old male patient presented with a 7-month history of non-specific gastrointestinal symptoms. He performed with vomiting, anorexia, right lower abdominal pain, and weight loss. These symptoms have been worsened, and he had multiple visits to the hospital for three months. He has been treated symptomatically in those visits. Apart from this, he has been well otherwise and has no past or family history for any systemic disease.

Upon his last visit, he was admitted to the inpatient department with a preliminary diagnosis of intestinal obstruction. On examination, the patient was thin, lean with a regular pulse of 96 bpm, BP of 110/70mmHg, R/R of 17/min, and body temperature of 98.6°F. He was pale, and his abdomen was distended with sluggish bowel sounds. There was a visible sausage-shaped gut impression on the anterior abdominal wall in the right lower region. His laboratory investigations were well within the normal range. There were multiple air-fluid levels on abdominal Xray. Abdominal ultrasound showed dilated gut loops with increased peristaltic activity and free fluid in the abdominopelvic cavity. His CT scan of the abdomen showed generalized dilatation of small bowel loops with prominent fold patterns along with the intussusception of a short segment of the small bowel. He has been diagnosed with intussusception, and he underwent a diagnostic laparoscopy followed by an exploratory laparotomy for this after informed consent. Per-operatively, there was an unpassable stricture in the jejunum, 1 foot from DJ, with marked dilation of proximal jejunum and stomach (fig.1). There were also enlarged mesenteric lymph nodes. Resection and primary anastomosis (fig.2) were done along with a mesenteric lymph node biopsy. The postoperative period was uneventful, and the patient was sent home on the 6th postoperative day after the commencement of the oral diet, which he tolerated well. The specimen was sent for histopathology, which later showed moderately differentiated adenocarcinoma of the jejunum (stage II – T3N0M0) and reactive lymphoid hyperplasia. The patient was discussed in an MDT, and he then underwent a metastatic workup, which was negative for any metastasis. He was advised for re-exploration for lymph node dissection and referral to a specialized oncology centre for adjuvant therapy, which, unfortunately, he refused. Nevertheless, he agreed to have a regular follow up on the OPD basis, and at a 6-month follow up, the patient was healthy and without any recurrence on radiological investigations.

Discussion:

Carcinoma of the small intestine is relatively rare as compared to other GI carcinomas. Although it is a significant portion of GI, covering 75% by length as well as 90% of the total mucosal surface, yet less than 2% of the whole GI carcinomas are from small intestine 8. The incidence has been recently increasing, with an annual frequency of 0.3–2.0 cases per 100,000 persons, with male predominance 7,9,10. It is common in 5th to 6th decade and incidence increases after the 4th decade. Though small bowel cancer commonly occurs in elderly patients, in this case, our patient was a young male guy.

Several risk factors predispose to small bowel cancer, including genetic, environmental, and medical conditions. Genetic risks include hereditary nonpolyposis colorectal cancer, familial adenomatous polyposis (FAP), and Peutz-Jegher syndrome 11. Whether environmental elements cause small bowel cancer is unknown. There is an increased risk of SBA in Alcoholics 12 and smokers 13. It is also common amongst the peoples who used sugar, carbohydrates, red meat and smoked food in large quantities. However, there is a reduced risk observed with higher intakes of coffee, fish, fruit, and vegetables 14,15. The industrialization has a higher occurrence rate for small bowel cancer though the underlying cause is unclear 16. Diseases like Crohn’s disease and Celiac disease may represent a subset of a pre-existing condition for small bowel cancer 17,18,19. However, in our patient, no such risk factor was found.

The clinical features and diagnosis of SBM are usually late. The initial symptoms are typically vague and include abdominal pain and discomfort 11. The common presentations include abdominal pain, abdominal distension, bleeding, and jaundice 20. Bowel obstruction is a common phenomenon in cases of the jejunal and ileal tumour but is less common in proximal duodenal tumours (47% vs 34%; p = 0.06) 21. SBM has usually presented as emergencies like occlusion (40%), bleeding (24%), perforation, and intussusception 11, which was also the case in our patient, who had emergency surgery for the suspicion of intussusception.

Earlier, vague clinical presentation along with the limited sensitivity of the contrast studies and abdominal X-rays for small bowel neoplasms had been the reason for delayed diagnosis. However, recent advancements in CT-Scan imaging, refinements in enteroscopy, and the invent of wireless capsule endoscopy have facilitated the diagnosis of small bowel adenocarcinoma 5. Different tools are widely available now for the determination of SBM, and they include; Small bowel follows through (sensitivity is 50%), CT scan (accuracy of 47%), capsule endoscopy (sensitivity is between 88.9% and 95%) and CT Enterocolysis 11,22,23. Studies have proven that CT Enterocolysis using spiral and multi-detector with an oral contrast has matched the radiographic test of choice for SBM, with the sensitivity of 100% 5,24.

According to the French guidelines, a CT scan of thoraco-abdominal and pelvic cavities to evaluate distant metastases, along with EGD and colonoscopy to exclude synchronous growths, are advised 25. CEA and CA 19-9 assay have a prognostic value, especially in advanced disease. 26. Testing for celiac disease, Crohn’s disease, and Lynch syndrome are also recommended in the backgroundof genetic predisposition 11. In this case, the patient underwent a CT scan abdomen preoperatively, which helped to make the diagnosis of intussusception. Later, he had a CT scan of the chest to rule out metastasis, which was normal.

Sadly, there had been no significant enhancements in consequences and survival in SBM in the last two decades, and the treating modalities have mainly continued unchanged 27. Although Surgical resection is the treatment of choice for SBM, Curative resection of the tumour is possible in only 40-65% of the cases as by the time when it is diagnosed; it is too late for cure 28. For localized SBM, Complete en-bloc removal of growth along with locoregional lymph node resection is associated with better outcomes. It is often required even in metastatic disease due to the high probability of obstruction or severe hemorrhage 7,11. For unresectable SBM, by-pass surgery as the palliative procedure is a suitable option. Recurrence, even after surgery, is high (40-60%), and it is mainly systemic 20. Also, until now, no effective adjuvant or palliative regimen has been recommended for SBM 7. Our patient had resection and anastomosis of the jejunum along with the lymph node biopsy. His histopathology confirms moderately differentiated adenocarcinoma with clear resection margins and reactive lymphoid hyperplasia without any signs of malignancy in the lymph node. Although our patient is doing fine at a 6-month follow-up, the prognosis of the SBM is poor and correlated to the tumour stage, with a 5-year overall survival rate ranging from 14% – 33% 29,30.

Conclusion:

The global prevalence of small intestine adenocarcinoma is rare, and particularly in Pakistan, the literature available is scarce. This report highlights the need that physicians should broaden their diagnostic vision for the suspicion index for these adenomas in patients with vague abdominal symptoms.