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Abstract
Renal cell carcinoma (RCC) is an unpredictable malignancy, with 25%–30% of patients developing metastatic disease. The most common sites of metastasis are the lung, bones, liver and brain, with small intestine metastasis being minimally reported in the literature. This report describes a case of small bowel obstruction caused by metastatic RCC in a male patient in his 60 s who had previously undergone a radical nephrectomy with adjuvant pembrolizumab therapy 6 years prior. The patient underwent a diagnostic laparoscopy converted to a laparotomy due to the complexity of the case. During surgical exploration, an enterectomy and end-to-end anastomosis were performed. This case emphasises the possibility of RCC metastasising to the small intestine, which may present with small bowel obstruction, while highlighting the importance of patient education for early detection to improve prognosis. Additionally, this report discusses treatment options for managing RCC metastasis to the small intestine.
- Small intestine cancer
- Renal medicine
- Gastrointestinal surgery
- Gastroenterology
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Background
Renal cell carcinoma (RCC) constitutes a majority of diagnosed primary renal neoplasms. Its occurrence is primarily observed in men between 50 and 70 years, with multiple associated risk factors, including hypertension, older age, polycystic kidney disease and hereditary diseases. Approximately 63 000 new incidences and 14 000 deaths are reported from RCC annually,1 with 25%–30% reporting metastatic disease at the time of diagnosis. The most commonly affected sites of metastasis include the lungs (45%), bones (30%), lymph nodes (22%), liver (20%) and brain (9%), while the involvement of the small bowel is exceedingly rare, with only a few published case reports available.2 3 However, metastasis to the small bowel may be more common than caseloads suggest, and the prognosis associated with metastatic RCC is grim. Median survival time typically ranges between 6 and 12 months, with a 2-year survival rate of 10%–20%.4 Therefore, educating the population on early recognition and evaluation is of utmost importance, particularly in the presence of risk factors, as stage 1 tumours have a 90% 5-year survival rate. Unfortunately, many early cases (25%) are asymptomatic, and the classic triad of flank pain, haematuria and palpable mass on physical examination is present in only 10% of individuals.1 Consequently, it is essential to emphasise patient education and enhance physician awareness to improve the prognosis for individuals at risk of developing this disease.
Case presentation
A man in his 60 s with a medical history significant for hypertension, iron deficiency anaemia treated with iron supplements and a past diagnosis of RCC followed by a right nephrectomy and adjuvant pembrolizumab chemotherapy 6 years prior presented to the emergency department with complaints of constipation and recurrent episodes of nausea and vomiting for the past week.
On examination, the patient exhibited hypertension, a blood pressure reading of 171/95 and tachycardia, with a heart rate of 109 beats per minute. Gastrointestinal examination findings revealed mild abdominal tenderness in all quadrants and mild distension. A CT scan revealed a small bowel obstruction likely caused by a stricture. A nasogastric tube was placed for gastric decompression. Subsequently, a small bowel series was conducted, but it failed to pass appropriately into the colon, indicating the necessity for surgical intervention. Following adequate resuscitation and correction of electrolyte imbalances, the patient was taken to the operating room for a diagnostic laparoscopy, where several centimetres of erythematous and woody small bowel were discovered as the source of the obstruction. Consequently, the laparoscopy was converted to a laparotomy, and a segment of the affected small bowel was surgically removed. A primary side-to-side anastomosis was then performed to reconnect the healthy portions of the bowel.
Investigations
The patient had been experiencing worsening constipation for several weeks following treatment with iron supplements for anaemia. He underwent an evaluation at an external institution due to similar concerns 6 days before the present visit. During that evaluation, he was prescribed lactulose, MiraLax and Senna to alleviate his constipation. An initial abdominal and pelvic CT scan revealed a mid to distal small bowel obstruction attributed to a stricture in the small bowel. The patient did not exhibit any signs of fever or leucocytosis at the time. Non-operative management was implemented, involving nasogastric tube decompression, intravenous fluids and treatment with piperacillin-tazobactam. His condition stabilised, and he was discharged in a stable state after 3 days, with the ability to tolerate oral intake.
However, 3 days later, he presented to our institution with worsening symptoms and sought evaluation in the emergency room for suspected small bowel obstruction. A comprehensive workup was conducted, including relevant laboratory tests that showed stable microcytic anaemia indicated by a haemoglobin of 10.4 and a haematocrit level of 34.3. CT imaging revealed a partial obstruction in the small bowel with a suspected transition point located centrally in the lower abdomen. After surgical consultation, nil per os status, nasogastric decompression, intravenous fluid resuscitation and a small bowel series were recommended. Following the completion of the small bowel series, which confirmed a complete obstruction, the decision was made to proceed with surgical intervention. The patient consented to a diagnostic laparoscopy with the possibility of a laparotomy.
Treatment
After the small bowel series failed to demonstrate the appropriate contrast passage into the colon within the expected timeframe, the patient provided informed consent for a diagnostic laparoscopy with the potential need for a laparotomy. Intraoperatively, no significant adhesions were encountered, and there were no indications of peritoneal, diaphragmatic or solid organ seeding. The small bowel was then run and exhibited a 50 cm erythematous, tortuous, thickened and woody segment. Consequently, the decision was made to convert to laparotomy to resect the affected portion of the small bowel. The bowel in question was brought extracorporeally. The involved distal jejunum, proximal ileum and bulky lymphadenopathy were resected pie-shaped, and a stapled side-to-side anastomosis was created. Incidentally, a Meckel’s diverticulum was appreciated and was left in place given no signs of appreciable disease. The patient was subsequently transferred to the surgical department for postoperative care.
Outcome and follow-up
The patient’s postoperative recovery proceeded without complications. Over the following days, he demonstrated bowel activity that led to removing his nasogastric tube. He successfully tolerated a diet and experienced a complete restoration of bowel function. As a result, he was discharged home on day 6 following the operation.
The resected specimen was sent to the pathology department for examination. Macroscopically, the small bowel exhibited a white-tan firm area, with a thickened wall measuring 10.3 cm in circumference (figure 1). This area appeared to involve the serosa, mucosa, submucosa, muscularis propria and attached mesenteric tissues. The pathology report revealed the presence of metastatic RCC (figure 2). The carcinoma displayed prominent necrosis, haemorrhage/thrombus and extensive sarcomatoid features involving the mucosa, submucosa, muscularis propria, subserosa and serosa. Extensive lymphovascular invasion was also observed. Peri-intestinal lymph nodes revealed metastatic RCC involving 10 of 13 lymph nodes. The portion of the metastatic RCC without sarcomatoid features present in the resected bowel specimen displayed morphological similarity to the patient’s previously diagnosed RCC from the right nephrectomy performed 6 years prior, as well as the lymph node biopsies taken from station 7 and station 4L 5 years ago.
Left: The postoperative specimen of the small bowel displays a white-tan firm area with a circumferential thickened wall. Right: The dissected postoperative specimen shows white-tan nodules involving the serosa, mucosa, muscularis propria and attached mesenteric fatty tissues.
The results of the histological examination were consistent with metastatic renal clear cell carcinoma showing neoplastic cells with clear cytoplasm arranged in nests with intervening blood vessels.
The patient attended a follow-up appointment at the clinic 5 weeks after the operation. A well-healing incision was noted, with a seroma at the distal incision site, measuring the size of a golf ball. However, there were no signs of erythema or drainage. After undergoing a positron emission tomography (PET) scan 7 weeks postoperation, the patient returned for another follow-up visit. The PET scan revealed positive metastasis in three lymph nodes without reported complaints during this visit. The patient was subsequently scheduled for further management with oncology.
Discussion
RCC originates from the renal cortex. The exact causes of RCC are not fully understood, although several risk factors have been identified, including advanced age, hypertension, nephrolithiasis and polycystic kidney disease. Hereditary diseases, such as tuberous sclerosis, Von Hippel-Lindau syndrome, Birt Hogg-Dube syndrome and exposure to certain occupational hazards like asbestos and herbicides, are also associated with an increased risk of RCC. However, most cases are sporadic and are found incidentally.1 Additional imaging, such as CT or MRI with intravenous contrast, is recommended for incidentally found indeterminate renal masses, with a specific approach determined based on the Bosniak Class.5
Treatment options for RCC are determined by the American Joint Committee on Cancer (AJCC) staging system (Eighth Edition, 2017). ‘For stage I renal cell cancer measuring less than 7 cm and confined to the kidney, nephrectomy or partial nephrectomy is the treatment of choice and is usually curative…For stage II renal cell cancer, laparoscopic radical nephrectomy is the treatment of choice. For stage III renal cell cancer, open radical nephrectomy is the standard of care. Adrenalectomy or extensive lymph node dissection is only recommended when abdominal CT shows evidence of adrenal or lymph node invasion. Stage IV renal cell cancer is not curable. Treatment is palliative…’.1
Our patient had undergone a right radical nephrectomy 6 years prior for a right renal mass that had invaded perinephric tissues. The final pathology report showed a multifocal clear RCC with a Fuhrman grade 3. Two masses measuring 7.0 and 9.0 cm, respectively, were excised. The primary tumour was classified as T3a NX. Treatment was appropriate per the AJCC staging system (Eighth Edition, 2017), as no definitive lymph nodes were found in the specimen, and extensive lymph node dissection was not indicated. At the current presentation, small bowel metastasis advanced the patient’s stage to IV.
RCC often remains asymptomatic in the earlier stages and exhibits non-specific signs. The management of RCC requires a multidisciplinary approach. Mortality rates have decreased due to improved detection and treatment strategies, underscoring the importance of patient education. The prognosis of RCC significantly improves when diagnosed at earlier stages, as the 5-year survival rate drops from over 90% to below 40% once lymph node involvement occurs.
Other sporadic RCCs metastasis to the small bowel cases have been reported, with patients presenting symptoms such as haematochezia and anaemia. In one such case, the patient had the affected bowel segment resected and was then placed on palliative radiation therapy due to metastasis to the bone and brain. The patient passed away from complications of coronary artery disease within a few months. In the second case, the patient had the affected bowel segments resected and was not put on any systemic therapy. The patient was then put on surveillance every 6 months. In the last such case, the patient was prescribed pembrolizumab due to brain metastasis 2 months after resection.2
The small bowel is difficult to evaluate through endoscopic and radiological techniques; the disease, if present, is often advanced at the time of examination. The optimal imaging strategy for small bowel assessment remains unclear. Enteroscopy, performed via oral and anal approaches, is recommended and should not be limited to the upper digestive tract. CT/MR enterography is the preferred diagnostic and staging modality, while PET-CT can aid in initial diagnosis and staging, although it is not routinely recommended. Small bowel video capsule endoscopy has limitations due to its inability to obtain tissue samples and its restricted use in cases of small bowel obstruction, with a reported false negative rate of up to 18.9%.6
RCC is staged through Tumour, Node, Metastasis (TNM) classification. It defines stage IV as T4 (invasion beyond Gerota’s fascia or involvement of the ipsilateral adrenal gland), any N (lymph node metastasis), M0 (no distant metastasis) or any staging with M1 (distant metastasis).7 Stage IV can be further categorised into oligometastatic disease. While definitions for oligometastatic state vary, it represents an intermediate stage between localised and widespread disease with limited metastatic growth potential, with various authors citing ≤5 metastatic lesions.8
Oligometastatic RCC management involves targeted local therapies like surgery or radiation, while polymetastatic disease requires systemic treatments. In managing oligometastatic RCC, stereotactic body radiotherapy (SBRT/SABR) has been used, particularly in poor surgical candidates, due to its non-invasive nature and modest morbidity profile. SBRT involves ablation of the target lesions while sparing surrounding tissue. Surgical intervention is preferred for lesions greater than 7–8 cm. It was theorised that locally ablative therapies targeting clinically evident metastatic disease sites could improve prognosis. However, data on the topic is limited, and such treatment’s efficacy remains controversial. There is emerging evidence that SBRT may be able to reverse antitumor immunity, although the underlying mechanisms are not yet fully understood.8 The RAPPORT trial prospectively evaluated SBRT and immunotherapy in patients with oligometastatic RCC. The trial demonstrated total metastatic ablation’s safety and local effectiveness using radiotherapy and pembrolizumab. However, further research is needed to explore the potential benefits of SBRT and immunomodulators in this context. Patients with limited disease and short disease-free intervals may be at risk of developing additional metastasis and potentially benefit from SABR. This field of research is continuously evolving, and more studies are required to investigate the role of immunomodulators in managing oligometastatic RCC.9
Learning points
Renal cell carcinoma is an unpredictable malignancy, and while the most common sites of metastasis are the lung, bone, liver and brain, it is essential not to overlook uncommon sites such as the small intestine. Metastasis can indicate a poor prognosis for this disease.
Ongoing surveillance following nephrectomy for renal cell carcinoma is crucial as a significant percentage of patients (20%–50%) can still develop metastatic disease.
Managing complicated cases, as in this case, requires a multidisciplinary approach involving various medical specialities. Collaborative decision making and treatment prioritisation are necessary to ensure optimal patient care.
Both the continuous education of healthcare providers and patient education play a role in patient care. Educating patients about the signs of the disease can lead to early detection, which is crucial in improving prognosis. Healthcare providers must also stay informed about the latest medical treatments and management strategies advancements.
Ethics statements
Patient consent for publication
Footnotes
Contributors DK and JL saw and treated the patient in the hospital. DK, GR and KKE collected data for the case report. DK, GR and KKE contributed to all portions of text including summary, background, case presentation, investigations, treatment and discussion. DK, GR and KKE looked up the literature and focused on discussion. JL served as the overall supervisor, providing guidance, editing the paper, and completing outcome and follow-up. He contributed additional information to discussion. All authors contributed to the learning points, revisions and final approval/submission of the paper. The following authors were responsible for drafting of the text, sourcing and editing of clinical images, investigation results, drawing original diagrams and algorithms, and critical revision for important intellectual content: DK, GR, KKE and JL. The following authors gave final approval of the manuscript: DK, GR, KKE and JL.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.