Following the surgery, adjuvant chemotherapy consisting of fluorouracil (425 mg/m²) plus folinic acid (20 mg/m2) for 5 days every 4 weeks was started. After the 3^rd cycle, pelvic chemo-radiotherapy was given, and then he received 3 more cycles, making a total of 6 cycles of chemotherapy.

Almost a year after the completion of adjuvant therapy, bilateral multiple pulmonary metastatic nodules appeared. The combination of fluorouracil and folinic acid was tried again, but the metastatic lesions did not respond.

One month later, he developed diplopia on looking to the left, deviation of the mouth to the left and a hearing loss together with tinnitus. On the neurological examination, the left eye was unable to turn up and outward down and there was a left-sided peripheral facial paralysis and hearing loss on the same side, making the diagnosis of left 4^th, 6^th, 7^th and 8^th cranial nerve palsies. The head and neck examination was normal. There was no mass in the nasopharyngeal area. Magnetic resonance imaging demonstrated multiple metastatic lesions in the right lateral bulbus, anterior pons, in the left trigon and in the 4^th ventricle.

Dexamethasone 4x4 mg P.O. was started immediately and palliative radiotherapy at a total dose of 3000 cGy in 10 fractions was instituted. Diplopia regressed after the 7^th fraction. Irinotecan 100 mg/m² once a week for 28 days with a 15-day rest was started following a 10-day rest after the radiotherapy. He died suddenly one month after discharge from the hospital.

In colorectal cancer, the most common sites of metastasis are liver and lungs. Although the liver is the primary site of metastasis, rectal adenocarcinoma may develop extra-abdominal dissemination in 4% of cases skipping it due to inferior rectal vein collaterals[3,4]. As proposed for some other tumors, the extra-abdominal metastasis of rectal carcinoma including CNS may be through Batson plexus, which has rich collaterals from the pelvis up to the skull[5].

In one study, the majority of the patients with brain metastasis have concomitant extracerebral metastasis especially in the lung as in our case[6]. Once CNS involvement occurs, life expectancy dramatically diminishes: Only 16% of patients live longer than a year[6]. Infratentorial localisation and multiple lesions define poorer prognosis[7]. Whenever possible metastatectomy with or without radiotherapy seems to be the best treatment option prolonging the survival up to 6 months or more[6,7].

In our case, CNS involvement was both infratentorial and multiple. Surgical removal was impossible. As expected, his fate was grave. Although the presentation with multiple cranial nerve palsies is rare, it must be remembered that the clinical picture may herald brainstem metastasis and resultant possible cerebellar herniation. Therefore, corticosteroids and palliative radiotherapy must be started immediately.

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2) DeAngelis LM, Posner JB. Cancer of the central nervous system and pituitary gland. In: Lenhard RE, Osteen RT, Gansler T, editors. Clinical Oncology, 1st ed. Malden: Blackwell Science Inc, 2001;653-703.

3) Penfold JC, Mann CV. An unusual metastasis of carcinoma of rectum. Br J Surg 1973;60:325.

4) Araki K, Kobayashi M, Ogata T, et al. Colorectal carcinoma metastatic to skeletal muscle. Hepato-Gastroenterol 1994;41:405-8.

5) Geldof AA. Models for cancer skeletal metastasis: A reappraisal of Batson's plexus. Anticancer Res 1997;17:1535-9.

6) Farnell GF, Buckner JC, Cascino TL, et al. Brain metastasis from colorectal carcinoma, the long-term survivors. Cancer 1996;78:711-6.

7) Wroński M, Arbit E. Resection of brain metastasis from colorectal carcinoma in 73 patients. Cancer 1999;85:1677-85.