A 24-year-old female with KMS was referred to our hospital with a subdural hematoma. Persistent, severe headache and neck pain began 10 days earlier, and she had a negative history of trauma. She had migraine without aura, psoriasis, and KMS. KMS was diagnosed at another medical center. Her general physical examination showed large cutaneous hemangiomas in her extremities, with left side predominance. Two fingers on her left hand had been amputated. Her neurological examination was normal. Blood analysis findings were thrombocytopenia (platelet count: 87 x 109/L), hypofibrinogenemia, and a high D-dimer level (5000 ng/ mL [normal: 147 ng /mL]). The fibrinogen level was 40 mg /dL (normal range: 175-400 mg/ dL). Other hemogram parameters (hemoglobin level: 12.6 g/dl, white blood cell count: 6.1 x 109/L, hematocrit level: 36.1 %) and laboratory findings were normal. Cranial MRI showed a bilateral subacute subdural hematoma in the frontotemporoparietal region and subacute hemorrhage in the right tentorial region (Figure A-C). Fresh frozen plasma (3 units) was administered to treat hypofibrinogenemia within 3 days after admission, and the patient was given bed rest with head elevated for 15 days.Amitriptyline and analgesic drugs were initiated from the first day of admission. Two months later after discharge from hospital, she did not state any complaints and cranial CT showed a reduction in the size of the subdural hematoma.