Leptomeningeal carcinomatosis in a young patient with obstructive colorectal signet- ring cell adenocarcinoma.

We present the case report of a twenty-five-year-old Moroccan male patient who suffered from leptomeningeal carcinomatosis related to a signet-ring cell carcinoma of the rectum. He presented to the emergency department with abdominal pain, constipation, weight loss and rectal bleeding. The rectal examination showed a rectal tumor and a CT scan revealed a large bowel obstruction due to rectal diffuse thickening. An emergency transverse colostomy was performed, with a rectal biopsy and a cytological sample collection. The pathology analysis showed a signet-ring cell carcinoma from the rectum. The staging evaluation was completed and neoadjuvant chemotherapy and radiotherapy were offered to the patient. Two months later, he developed neurological signs of leptomeningeal involvement which was confirmed by a lumbar puncture. Then, the patient received systemic and intrathecal chemotherapy but later died. This case shows the tendency of colorectal signet-ring cell carcinomas to cause leptomeningeal metastasis, even in young patients.