Calcified chronic subdural hematoma or ossified chronic subdural hematoma (CSDH), characterized by slowly progressing neurological symptoms, is a rarely seen entity that may remain asymptomatic for many years.

Incidence of calcified or ossified CSDH is high in certain countries, including the USA, Japan and Turkey, with a steady increase in recent years ¹⁾.

They should be considered in the differential diagnosis at the time when we encounter because of its infrequency and variable clinical manifestation, following shunting in children or head trauma in adults ²⁾.

Calcified epidural hematoma, calcified empyema, meningioma, calcified arachnoid cyst, and calcified convexity of the dura mater with acute epidural hematoma should be considered for the differential diagnosis ³⁾.

Management of CSDH has improved dramatically in recent years thanks to advances in diagnostic tools, but there is still some controversy regarding the optimal treatment strategy.

In a systematic review, PRISMA guidelines were followed to query existing online databases between January 1930 and December 2018. We found a total of 88 articles containing 114 cases of calcified or ossified CSDH, 83 patients operated and 31 ones not operated.

There were 78 males and 29 females (7 with unreported gender) from 25 countries, ages ranging from 4 months to 86 years (mean 33.7 years), with etiologies of head trauma in 33.3%, shunting for hydrocephalus in 27.2%, or following cranial surgery in 4.4%. The duration of symptoms ranged from acute onset to 20 years, with a mean of 24.1 months. Imaging techniques such as X-ray, computed tomography, and magnetic resonance imaging were used with pathological confirmation of CSDH and complete recovery in 56.4% of patients.

Incidence of calcified or ossified CSDH is high in certain countries, including the USA, Japan and Turkey, with a steady increase in recent years. Therapy of choice is surgery in these patients and it should be considered in the differential diagnosis at the time when we encounter because of its infrequency and variable clinical manifestation, following shunting in children or head trauma in adults ⁴⁾.

Yang X, Qian Z, Qiu Y, Li X. Diagnosis and Management of Ossified Chronic Subdural Hematoma. J Craniofac Surg. 2015 Sep;26(6):e550-1. doi: 10.1097/SCS.0000000000002025. PubMed PMID: 26352368.

A 59-year-old man presented with epileptic seizures interpreted as episodic syncope in the past 3 years and the patient had a history of head trauma about 4 years ago. Computed tomography revealed an ossified chronic subdural hematoma involving the right frontotemporoparietal region, which was totally resected using microsurgical technique. Postoperatively, weakness developed in the right arm and magnetic resonance imaging revealed a bilateral tension pneumocephalus, which was immediately treated by a left frontal burr hole trepanation, and the patient was discharged uneventfully ⁵⁾.

A 46-year-old man with a history of alcohol abuse and a right frontotemporoparietal and left frontal ossified CSH that was diagnosed 2 years previously presented with headache and memory loss over 6 days. The patient was being followed with serial imaging, which showed the static state of the mass and no other lesions 7 months before admission. He underwent right frontotemporoparietal craniectomy to remove the ossified CSH and tumor. When the bone was lifted and the thin dura was opened, a hard, thick, ossified capsule was observed. No apparent tumor invasion was noted in the skull or epidural space. Despite refusing further chemotherapy and radiation therapy, the patient has been disease-free and working for 5 years.

Based on reported cases and relevant literature, large B-cell lymphoma may be associated with ossified CSH ⁶⁾.

A 81-year-old woman with calcified chronic subdural hematoma. The patient underwent an osteoplastic left craniotomy, evacuation of chronic subdural mass with careful dissection and successful removal of the inner and outer membrane. Postoperative CT scan showed removal of subdural hematoma, a decrease of the left shift of median line and good brain re-expansion. The postoperative period was without any serious complications.

The subdural hematoma was successfully removed, resulting in a good recovery with complete resolution of patient’s symptoms. They highly recommend surgical treatment in cases of chronic symptomatic calcified subdural hematomas ⁷⁾.

A Giant Ossified Chronic Subdural Hematoma ⁸⁾.

Fang et al. reported a case of ossified chronic subdural hematoma in a 7-year-old female child, with a literature review ⁹⁾.

Siddiqui et al. reported one case with diabetes insipidus ¹⁰⁾.

A young girl affected by a syndromal hydrocephalus who developed a bilateral ossified chronic subdural hematoma with the typical radiological appearance of “the armored brain”. Bilateral calcified chronic subdural hematoma is a rare complication of ventriculoperitoneal shunt. There is controversy in the treatment, but most published literature discourages a surgical intervention to remove the calcifications ¹¹⁾.

Turgut et al. published one Ossified chronic subdural hematoma ¹²⁾.

A 22-year-old male who had presented with severe headache consequent to brain compression caused by bifronto-parieto-temporal ossified subdural hematoma. We evaluated our method and surgical intervention in the light of the literature. The question whether the ossified membrane should be excised or not excised in these cases is a matter of controversy. They think that an ossified membrane causing an armored brain appearance should be excised in symptomatic, young patients with prominent cerebral compression. During this dissection, the relatively thickened arachnoid mater provides a safe border ¹³⁾.

A 67-year-old man presented with headache, dysphasia, and left-sided hemiparesis. Routine skull x-ray showed a huge calcification extending from the frontal to the parietal regions in the right side. CT and MRI scan revealed a huge ossified SDH covering the right hemisphere. Right frontoparietal craniotomy was performed and the ossified SDH was completely removed. Severe adhesion was noticed between the pia mater and the inner surface of the ossified mass. The subdural mass had ossified hard outer and inner rims and a soft central part. The postoperative course was uneventful and 3 months after the operation, the patient was neurologically intact. The authors report the successful treatment of a patient with a huge ossified SDH covering the right hemisphere. Careful dissection and total removal are needed in such symptomatic cases to avoid cortical injury and to improve results ¹⁴⁾.

A 24-year-old man with a history of tonic-clonic convulsions since 7 months of age was admitted because of increasing frequency and duration of seizures. Computed tomography and magnetic resonance imaging demonstrated a fusiform extra-axial lesion just above the tentorium and adjacent to the cerebral falx. A calcified and ossified chronic subdural hematoma was noted and was almost completely removed by craniotomy. Better seizure control was achieved by the removal of the calcified chronic subdural hematoma. Calcified subdural hematoma, calcified epidural hematoma, calcified empyema, meningioma, calcified arachnoid cyst, and calcified convexity of the dura mater with acute epidural hematoma should be considered for the differential diagnosis of an extra-axial calcified lesion ¹⁵⁾.

Turgut et al. reported the successful removal of an ossified crust-like chronic subdural hematoma (SDH) covering the hemisphere in a 16-year-old boy. In this article, the importance of the surgical approach is stressed, and the rarity of this condition in the neurosurgical literature is also outlined ¹⁶⁾.

A case of ossified chronic subdural hematoma is presented in a 13-year-old male in whom the mass was surgically removed. His neurological deficits continued afterward but were less severe ¹⁷⁾.