Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 19 3 2025 07 21 303 306 Ruchee Khanna Department of Pathology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Karnataka, India Nithya Prem Department of Pathology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Karnataka, India Vishwapriya Godkhindi Department of Pathology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Karnataka, India Geetha V Department of Pathology, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Karnataka, India 2024 05 13 2024 11 02 Medulloblastoma is the most common primary CNS malignant neoplasm in the paediatric age group, accounting for 12 to 20 % of all childhood malignancies, but medulloblastoma in an adult is rare. We report a case of a 31-year-old male who presented with an inability to walk and episodic vomiting. MRI of the brain revealed a midline lesion involving the vermis and cerebellar hemispheres. Excision and immunohistochemistry confirmed the diagnosis of medulloblastoma, desmoplastic/nodular. After 10 months, he had a recurrence of the tumour and a redo surgery was attempted, followed by 6 # cycles of chemotherapy. The patient was lost to follow-up; 3 years later, PET-CT showed multiple metastases to the lung and cervical lymph node along with bicytopenia. The bone marrow study revealed interstitial infiltration by small round blue cells. Immunohistochemistry showed these cells were positive for synaptophysin, supporting a diagnosis of medulloblastoma metastasis to the bone marrow. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/2242 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/2242/1096