Special Issue "Machine Learning Applications in Bioinformatics and Biomedicine: 3rd Edition".

Chronic subdural hematoma is a common condition affecting patients undergoing neurosurgery and is particularly prevalent among older adults. Burr-hole drainage has become the preferred treatment for CSDH, as it is a relatively simple, minimally invasive procedure with a generally good safety profile. Secondary intracranial fungal infection following CSDH surgery is exceedingly rare. Fungal infections of the central nervous system (CNS) are among the diseases with the highest global morbidity and mortality, but are relatively uncommon, accounting for less than 5% of all CNS infections []. In several retrospective cohorts, Aspergillus species were identified as a leading cause of fungal CNS infections [, ], and they are the primary pathogens associated with infections following neurosurgical procedures—particularly transsphenoidal surgery—potentially from Aspergillus contamination of the paranasal sinuses []. Morioka et al. previously reported a case of cerebral aspergillosis occurring 2.5 years after burr-hole drainage for CSDH, with a clinical course resembling a brain tumor []. parapsilosis is an important non-albicans species that has been increasingly reported as a cause of infections among immunocompromised patients, neonates, and patients with indwelling devices in recent years []. This species has a particular affinity for artificial materials and can form biofilms on plastic surfaces, making it a significant cause of device-associated infections []. C. parapsilosis has been found to cause CNS infections, including meningitis, ventriculitis, and brain abscesses [, ]. Device-related CNS infections caused by C. parapsilosis have been reported in both infants and adults, with amphotericin B or fluconazole comprising standard treatment regimens for affected patients []. To the best of our knowledge, no previous report has described intracranial C. parapsilosis infection occurring years after burr-hole surgery for CSDH. Here, we present such a case, diagnosed 2 years postoperatively. Diagnosis was established through pathological examination of the organized hematoma membrane obtained during the second surgery and subsequent CSF culture. This case report and associated literature review aim to detail the clinical characteristics, diagnostic pitfalls, and treatment strategies for this rare but serious complication. The patient was a 66-year-old male with a history of hypertension and schizophrenia. He had no history of immunodeficiency disorders and had not received glucocorticoids or immunosuppressive agents. Two years prior to presentation, he underwent bilateral burr-hole drainage at another hospital for management of bilateral frontotemporoparietal CSDH. Intraoperative drainage was limited, and his postoperative course was uneventful, with no fever incidence. The drain was removed 48 h post-surgery, and good wound healing was observed, with eventual discharge after symptomatic improvement. Over the 2 years following this procedure, the patient experienced recurrent, progressively worsening headaches, accompanied by involuntary tongue protrusion and limb shaking. His body temperature remained normal. Ten days before admission to our hospital, he suffered a generalized tonic-clonic seizure that resolved spontaneously after approximately two minutes. Review of computed tomography (CT) scans performed at the other hospital before and after the initial surgery 2 years earlier revealed persistent bilateral hematomas (). Upon admission, cranial CT revealed bilateral frontotemporoparietal CSDH of inhomogeneous density, including hyperdense areas, and a significant mass effect (). These hyperdense areas were suspected to represent the organization of the chronic hematoma. Given the patient’s progressive symptoms, which were attributed to persistent brain compression caused by the organized hematoma, it was concluded after discussion that burr-hole drainage or conservative management would not effectively drain the hematoma or relieve brain compression. Preoperative evaluation revealed no surgical contraindications, with serum immunoglobulin levels (IgG, IgA, IgM) that were within normal ranges. After appropriate preoperative preparation, the patient underwent bilateral frontotemporoparietal craniotomy for hematoma evacuation under general anesthesia. Intraoperatively, the hematoma membrane was found to be abnormally thickened and organized, measuring up to 1 cm at its thickest point, with a leathery, tough consistency. The cavity contained a small amount of yellowish fluid and abundant organized material with a “sandy” appearance (). These intraoperative findings differed from a typical CSDH case such that the hematoma membrane and its contents were sent for postoperative pathological examination. Craniotomy achieved substantial removal of the membrane and cavity contents.