The overall incidence of cerebral metastases continues to increase due to a variety of factors. Suggested reasons include the increasing length of survival of cancer patients due to improved treatment and management of systemic cancers, as well as earlier diagnosis due to the easy availability of imaging modalities. Other proposed reasons include the fact that many chemotherapeutic agents do not cross the blood-brain barrier (BBB), thereby making the brain a haven for metastases, and paradoxically, some chemotherapeutic agents may transiently weaken the BBB, allowing CNS seeding with tumor.
Intraventricular or choroid plexus metastases, particularly of colorectal origin, are a very rare occurrence. However, as the prevalence of systemic cancers continues to rise, there will likely be a corresponding increase in their diagnosis over time. Metastases from cancers of the gastrointestinal tract have not only been described in the brain, but also in head and neck regions such as the scalp. A recent systematic review by Paolino et al noted gastrointestinal cancers account for 24.4% of scalp metastases, five cases of which were secondary to rectal carcinoma. To our knowledge, there have only been four reported cases of intraventricular or choroid plexus metastases from a colon cancer origin, and no prior reports of one from a primary rectal cancer up to this point (Table 1)[1,3–5]. All the cases described in this study or others have been secondary to the histologic diagnosis of adenocarcinoma. Patient age, sex, number of lesions and time from initial diagnosis to intraventricular metastasis was reported in all but one of the four published cases of intraventricular or choroid plexus metastases from a colon cancer origin. The male to female ratio was 2 to 1. The mean age at diagnosis was 58, younger than our patient who was 72 years old at diagnosis. The mean time from initial diagnosis of colon cancer to intraventricular metastases was 4.7 years, while the patient in this study presented with concurrent primary rectal cancer and intraventricular metastases. The most common location of metastasis is the lateral ventricle, with only one prior case involving multiple ventricles. MRI of the brain revealed several enhanced intraventricular lesions within the right lateral ventricle, the fourth ventricle and bilateral foramen of Luschka (Fig. 2), making this case the second published report of multi-ventricular metastasis of colorectal origin, as well as the first published report of intraventricular metastasis from rectal cancer.
Case Author (year) Age (year)/
Primary tumor origin No. of
Diagnosis to metastasis (year) Histologic
1 Kohno et al (1996) 45/M Trigone of L lateral ventricle Sigmoid colon Solitary 3 Adenocarcinoma 2 Al-Anazi et al (2000) 81/M All ventricles Colon Multiple 8 Adenocarcinoma 3 Kitajima et al (2003) 48/F Inferior horn of R lateral ventricle Colon Solitary 3 Adenocarcinoma 4 Hassaneen et al (2010) NR Lateral ventricle Colon NR NR Adenocarcinoma Current Omofoye et al (2020) 72/M All ventricles Rectal Multiple 0 Adenocarcinoma F: female; L: left; M: male; NR: not reported; R: right.
Table 1. Reported cases of intraventricular metastases from colorectal cancer
Differences in the metastatic profile of colon and rectal cancer have been reported in the literature. Qiu et al queried the Surveillance, Epidemiology and End Results Program database for colorectal cancer, and noted a higher incidence of liver metastasis from colon cancer than from rectal cancer, while rectal cancer has a higher incidence of lung and bone metastases than colon cancer. Even though their study showed no difference in the rate of brain metastases from colon or rectal cancer, other studies have reported a higher risk of brain metastases in patients with primary rectal cancer. This difference has been explained by the venous drainage of the rectum which bypasses the liver and goes directly into the inferior vena cava. Lynch syndrome is most frequently caused by mutations in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2, leading to microsatellite instability. This patient's loss of two of these genes is consistent with a diagnosis of Lynch syndrome. However, his diagnosis of a WHO grade AB thymoma is not classically seen in Lynch syndrome, which is more commonly associated with colorectal cancer, gastric cancer, transitional carcinoma of the ureter and renal pelvis, glioblastoma, and in females, endometrial and ovarian cancers. Interestingly, there has been one published report of a stage IB malignant thymoma in a Lynch syndrome patient with three synchronous adenocarcinomas of the colon and multiple other cancers. Thymomas have been associated with other tumor types, most notably gastrointestinal cancers. It is unclear whether its occurrence in a Lynch syndrome patient such as this case, or as described by Tampellini et al, is directly or indirectly secondary to the same genomic instability mechanism responsible for their correlative colorectal cancers.
As the management of patients with systemic cancers continues to improve with medical discoveries and technological innovation, progressively older patients will have to be managed with therapies, often currently considered too aggressive for them. Surgical and anesthetic management will have to be modified to accommodate patients that have been classically considered non-surgical candidates. Due to this patient's thymoma and compression of his airway, he was deemed as an unsuitable candidate for intubation and general anesthesia for a more invasive resective surgery. After an intraventricular biopsy was considered, it was decided to proceed with an awake placement of Ommaya reservoir. This provided a strategy not only for diagnosis via CSF sampling, but also for possible treatment with intrathecal chemotherapy and CSF access if hydrocephalus were to develop. Awake neurological surgeries such as craniotomies for tumor resection and deep brain stimulation are well-established surgical modalities. But there have been few reports of Ommaya reservoir placements under local anesthesia. This report demonstrates that awake placement of Ommaya reservoir with AxiEM electromagnetic neuronavigation is a viable alternative for selected oncologic patients with intraventricular malignancy or metastases, who may not be candidates for general anesthesia or resective surgery.
Intraventricular or choroid plexus metastases are a very rare occurrence, particularly from primary colorectal cancer. Although rare, this diagnosis should always be considered in the differential for solitary or multiple intraventricular lesions. CSF sampling is a useful alternative to intraventricular biopsy for diagnosis of intraventricular metastases. Awake placement of Ommaya reservoir is a safe option in the management of patients with intraventricular metastases, especially those who cannot undergo general anesthesia.
Intraventricular metastases from rectal carcinoma: case report and literature review
- Received Date: 2018-12-25
- Accepted Date: 2019-06-04
- Rev Recd Date: 2019-05-01
- Available Online: 2019-08-28
- Publish Date: 2020-07-01
- cerebral metastasis /
- colorectal cancer /
- cerebrospinal fluid sampling /
- intraventricular tumors /
- Ommaya reservoir
Abstract: Intraventricular metastases are a rare occurrence, particularly from a primary colorectal malignancy. To our knowledge, this is the first report of intraventricular metastasis from rectal cancer. A 72-year-old male presented with a new diagnosis of multiple intraventricular lesions, an anterior mediastinal mass and a rectal mass. His workup revealed rectal adenocarcinoma with intraventricular metastases and an incidental thymoma. Ommaya reservoir placement was performed via an awake procedure rather than under general anesthesia due to airway concerns. Cerebrospinal fluid (CSF) cytology was positive for malignancy and consistent with adenocarcinoma. Two weeks postoperatively, the patient underwent whole brain radiation. Although rare, this diagnosis should always be considered in the differential for solitary or multiple intraventricular lesions. CSF sampling is a useful alternative to intraventricular biopsy for diagnosis of intraventricular metastases. Awake placement of Ommaya reservoir is a safe option in the management of patients with intraventricular metastases, especially those who cannot undergo general anesthesia.
|Citation:||Oluwaseun A. Omofoye, Emanuela Binello. Intraventricular metastases from rectal carcinoma: case report and literature review[J]. The Journal of Biomedical Research, 2020, 34(4): 318-322. doi: 10.7555/JBR.33.20180133|