PURPOSE:The number of leptomeningeal metastasis (LM) patients has increased in recent years, as the cancer survival rates increased. An optimal prediction of prognosis is essential for selecting an appropriate treatment. The European Association of Neuro-Oncology-European Society for Medical Oncology (EANO-ESMO) guidelines for LM proposed a classification based on the cerebrospinal fluid cytological findings and contrast-enhanced magnetic resonance imaging (MRI) pattern. However, few studies have validated the utility of this classification. This study aimed to investigate the prognostic factors of LM, including the radiological and cytological types. METHODS:We retrospectively analyzed the data of 240 adult patients with suspected LM who had undergone lumbar puncture between April 2014 and September 2021. RESULTS:The most common primary cancer types were non-small-cell lung cancer (NSCLC) (143 (60%)) and breast cancer (27 (11%)). Positive cytology results and the presence of leptomeningeal lesions on contrast-enhanced MRI correlated with decreased survival in all patients. Nodular lesions detected on contrast-enhanced magnetic resonance were a poor prognostic factor in cytology-negative patients, while contrast-enhanced patterns had no prognostic significance in cytology-positive patients. Systemic therapy using cytotoxic agents and molecular-targeted therapy after LM diagnosis correlated with prolonged survival, regardless of the cytology results. Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor treatment and systemic chemotherapy after LM improved the survival of EGFR-mutated and wild-type NSCLC patients with positive cytology results. CONCLUSIONS:This study validated the efficacy of prognostication according to the EANO-ESMO guidelines for LM. Systemic therapy after LM diagnosis improves the survival of NSCLC patients.

BACKGROUND:Meningeal carcinomatosis is a very rare metastatic site of gastric cancer and meningeal carcinomatosis without other metastatic sites is much extremely rare. Herein, we report our experience with a very rare case of meningeal carcinomatosis which was difficult to diagnose the recurrence by general systemic examination and was found due to the deafness despite the sustained high tumor markers. CASE PRESENTATION:A 68-year-old man consulted a hospital with vomiting and hematemesis. Laboratory tests revealed severe anemia. He was referred to our hospital and underwent an emergency gastroscopy, which revealed Borrman type 3 tumor and oozing of blood. Biopsy specimen showed gastric cancer. After several examinations, total gastrectomy was performed and tegafur-gimeracil-oteracil potassium (S-1) was initiated as adjuvant chemotherapy one month after surgery. Tumor marker levels (CEA and CA19-9) remained high for three months after surgery. S-1 was continued while shortening the imaging study follow-up period. Nine months after surgery, he noticed difficulty in hearing with facial paralysis, dizziness, tinnitus, and appetite loss. He was diagnosed with meningeal carcinomatosis and bilateral internal auditory canal metastasis. He died approximately two months later. CONCLUSION:Meningeal carcinomatosis should be considered if bilateral deafness and vestibulopathy develop after gastrectomy, even if no recurrence is apparent in the abdominal cavity.

A 66-year-old Japanese male patient was referred to Saitama Medical University International Medical Center for treatment of bladder cancer (clinical stage T2 or higher without metastasis), and underwent radical cystectomy with pelvic lymphadenectomy. The histopathological diagnosis was high-grade urothelial carcinoma (pathological stage T2bN2, ly1, v0) and 2 cycles of adjuvant systemic chemotherapy (gemcitabine plus cisplatin) were administered. At 15 months after the operation, mediastinal and lung hilar lymph nodes and multiple bone metastases were identified on computed tomography imaging. After 3 cycles of the previous regimen as salvage systemic chemotherapy, the lymph node metastases had shrunk and the bone metastases were stable; therefore, further chemotherapy was planned. At 26 days after the initiation of the 4th cycle, the patient felt nausea and lower limb weakness. Spinal and brain magnetic resonance imaging with contrast medium revealed diffuse enhancement at the surface of the spinal cord and brain. In addition, abnormal signal intensity in the subarachnoid space was observed on fluid-attenuated inversion recovery imaging; therefore, the patient was diagnosed with meningeal carcinomatosis (MC). Treatment, including whole-brain radiotherapy, was planned for MC; however, the patient's condition rapidly worsened and he succumbed to the disease 14 days after the diagnosis of MC. The definitive diagnosis of MC was confirmed at autopsy.