Safety and histopathologic yield of percutaneous CT-guided biopsies of the skull base, orbit, and calvarium.

PURPOSE: Although CT-guided biopsies of the calvarium, skull base, and orbit are commonly performed, the best approaches, efficacy, and safety of such procedures remain scantly described in the literature. This retrospective review of percutaneous biopsies illustrates several approaches to challenging biopsy targets and provides a review of procedural planning considerations and histopathologic yield. METHODS: A retrospective review of CT-guided biopsies of the skull base, calvarium, and orbit between 1/1/2010 and 10/30/2020 was conducted. Patient demographics and procedural factors were recorded, including lesion size and location, biopsy approach, and needle gauge. Outcomes were also noted, including CT dose length product, complications, and histopathologic yield. RESULTS: Sixty-one CT-guided biopsies were included in the final analysis: 34 skull base, 23 calvarial, and 4 orbital lesions. The initial diagnostic yield was 32/34 (94%) for skull base lesions, with one false-negative and one non-diagnostic sample. Twenty-one of twenty-three (91%) biopsies in the calvarium were initially diagnostic, with one false-negative and one non-diagnostic sample. In the orbit, 4/4 biopsies were diagnostic. The total complication rate for the cohort was 4/61 (6.6%). Three complications were reported in skull base procedures (2 immediate and 1 delayed). A single complication was reported in a calvarial biopsy, and no complications were reported in orbital biopsies. CONCLUSION: Percutaneous CT-guided core needle biopsies can be performed safely and with a high diagnostic yield for lesions in the skull base, calvarium, and orbit.

Ultrasound as a standalone tool for the management of pediatric calvarial dermoid cysts.

PURPOSE: Calvarial dermoid and epidermoid cysts are benign lesions common in pediatric neurosurgery. Diagnosis is primarily clinical, with frequent but inconsistent use of imaging. Dermoids have been shown to possess distinct sonographic features, but ultrasound (US) remains underutilized in their management. The purpose of this study is to investigate the independent reliability of US in managing pediatric calvarial dermoids and distinguishing them from other calvarial lesions. METHODS: A retrospective review of consecutive patients ≤ 21 years of age with surgically resected calvarial masses between 2017-2024 was performed. Demographic, clinical, and imaging data were analyzed. Pearson chi-squared tests were used for comparison of categorical variables and a binomial linear model was generated controlling for age, lesion tenderness, growth, and suture location. RESULTS: Fifty-nine patients with 61 lesions (31 in females; median age 13 months) were included. Dermoids were more common in younger patients (median age 12 months), along suture lines, and were less likely to present with tenderness (p < 0.001) or rapid growth (p = 0.003). Ultrasound was used in 83% of cases and was the sole imaging modality in 33%. On multivariate analysis, suture location was a significant positive predictor of a dermoid diagnosis (OR = 8.08, 95% CI = 1.67-44.18), while rapid growth was a significant negative predictor (OR = 0.08, 95% CI = 0.003-0.80). CONCLUSION: Ultrasound presents a sensitive and reliable method for the evaluation of most pediatric calvarial lesions, especially dermoid cysts, and warrants being part of standard workup. With appropriate patient selection, US obviates the need for additional imaging in pediatric patients.

Isolated infantile myofibroma of the calvarium: Report of a case with a literature review.

OBJECTIVE: Infantile myofibromatosis is a rare entity of childhood characterized by benign myofibroblastic tumors in the soft tissues, the bones, and occasionally the viscera. Solitary skeletal lesions are relatively uncommon. Calvarial involvement should be distinguished from more aggressive tumors for appropriate treatment. METHODS: We reviewed solitary infantile myofibroma of the calvarium and discussed the relevant computed tomography and magnetic resonance imaging findings along with differential diagnosis. A case study of the frontal bone in a 5-month-old girl was also presented. RESULTS: Fourteen cases were reviewed, including the current case. Of the 13 cases with known sex, eight were male and five female. The mean age was 3.03 with an age range of 0.41-9 years. Nine of the 14 tumors were in the frontal bone. The lesions were intradiploic with tabula interna and/or externa of the calvaria involvement. The mean largest diameter was 22.3 mm. Upon computed tomography, all the lesions were expansile and lytic, and hypoattenuated, isoattenuated or occasionally hyperatenuated. Calcification was not seen. On magnetic resonance imaging, most neoplasms were hypointense on T1-weighted and T2-weighted images. Neoplasms showed hypointense signal on diffusion-weighted imaging and hyperintense on apparent diffusion coefficient, without restricted diffusion in three cases. All lesions were intensely enhanced after gadolinium administration. Treatment was total surgical resection and recurrence was not observed during follow-up. CONCLUSIONS: Infantile myofibromas are rare, typically intradiploic expansile lytic lesions with tabula interna and/or externa involvement. Distinctive imaging features include the presence of hipointense signals on T2-weighted magnetic resonance images without restricted diffusion on diffusion-weighted imaging. A slow-growing, firm, painless, and nontender mass with supportive imaging findings should raise suspicion of the disease.

[Convexity hyperostotic meningioma en plaque: a systematic review]. / Ploskostnye giperostoticheskie meningiomy svoda cherepa. Sistematicheskii obzor literatury.

BACKGROUND: Planar hyperostotic meningiomas account for 2-9% of intracranial meningiomas. They are characterized by planar node following the contours of the inner surface of the skull. Hyperostosis is present in most cases. Timely diagnosis of skull base tumors is usually simple due to early involvement of the cranial nerves. However, convexity meningiomas en plaque usually reach large dimensions that complicates surgery and radiotherapy. OBJECTIVE: To analyze the current state of diagnosis, molecular biology and surgical treatment of hyperostotic meningiomas en plaque. MATERIAL AND METHODS: A systematic review was performed in accordance with the PRISMA guidelines. Searching for literature data included the following keywords: «planar meningioma¼, «hyperostotic meningioma¼, «meningioma en plaque¼, «infiltrative meningioma¼. We reviewed the PubMed and Google Scholar databases until May 2023 and enrolled only full-text Russian-, English- or French-language reports. RESULTS AND DISCUSSION: Among primary 332 reports, 35 references met the inclusion criteria. We found less severity or absence of focal neurological symptoms, comparable incidence of intracranial hypertension and no histological differences between planar and nodular meningiomas. Analysis of molecular biological features of planar meningiomas, including cell cultures, is feasible. There is no consensus regarding surgical treatment and radiotherapy. Most publications are case reports. CONCLUSION: The results of treatment of planar hyperostotic meningiomas, especially large and giant ones, are unsatisfactory. There is no a generally accepted algorithm for treating patients in the literature. This problem requires further research.

In vivo evaluation of bone regeneration using ZIF8-modified polypropylene membrane in rat calvarium defects.

AIM: The profound potential of zeolitic imidazolate framework 8 (ZIF8) thin film for inducing osteogenesis has been previously established under in vitro conditions. As the next step towards the clinical application of ZIF8-modified substrates in periodontology, this in vivo study aimed to evaluate the ability of the ZIF8 crystalline layer to induce bone regeneration in an animal model defect. MATERIALS AND METHODS: Following the mechanical characterization of the membranes and analysing the in vitro degradation of the ZIF8 layer, in vivo bone regeneration was evaluated in a critical-sized (5-mm) rat calvarial bone defect model. For each animal, one defect was randomly covered with either a polypropylene (PP) or a ZIF8-modified membrane (n = 7 per group), while the other defect was left untreated as a control. Eight weeks post surgery, bone formation was assessed by microcomputed tomography scanning, haematoxylin and eosin staining and immunohistochemical analysis. RESULTS: The ZIF8-modified membrane outperformed the PP membrane in terms of mechanical properties and revealed a trace Zn+2 release. Results of in vivo evaluation verified the superior barrier function of the ZIF8-coated membrane compared with pristine PP membrane. Compared with the limited marginal bone formation in the control and PP groups, the defect area was almost filled with mature bone in the ZIF8-coated membrane group. CONCLUSIONS: Our results support the effectiveness of the ZIF8-coated membrane as a promising material for improving clinical outcomes of guided bone regeneration procedures, without using biological components.

The Mechanical Characterization and Comparions of Male and Female Calvaria Under Four-Point Bending Impacts.

The circumstances in which we mechanically test and critically assess human calvarium tissue would find relevance under conditions encompassing real-world head impacts. These conditions include, among other variables, impact velocities, and strain rates. Compared to quasi-static loading on calvaria, there is less reporting on the impact loading of the calvaria and consequently, there are relatively fewer mechanical properties on calvaria at relevant impact loading rates available in the literature. The purpose of this work was to report on the mechanical response of 23 human calvarium specimens subjected to dynamic four-point bending impacts. Impacts were performed using a custom-built four-point impact apparatus at impact velocities of 0.86-0.89 m/s resulting in surface strain rates of 2-3/s-representative of strain rates observed in vehicle collisions and blunt impacts. The study revealed comparable effective bending moduli (11-15 GPa) to the limited work reported on the impact mechanics of calvaria in the literature, however, fracture bending stress (10-47 MPa) was relatively less. As expected, surface strains at fracture (0.21-0.25%) were less compared to studies that performed quasi-static bending. Moreover, the study revealed no significant differences in mechanical response between male and female calvaria. The findings presented in this work are relevant to many areas including validating surrogate skull fracture models in silico or laboratory during impact and optimizing protective devices used by civilians to reduce the risk of a serious head injury.

Pediatric focal calvarial lesions: an illustrated review.

Focal skull lesions in children can be diagnostically challenging with a wide variety of potential etiologies. Understanding the diverse pathologies and recognizing their associated clinical and imaging characteristics is crucial for accurate diagnosis and appropriate treatment planning. We review pertinent anatomy of the scalp and calvarium and review different pathologies that can present with focal skull lesions in pediatric patients. These include neoplastic, non-neoplastic tumor-like, congenital, post traumatic, and vascular-associated etiologies. We review the key clinical and imaging features associated with these pathologies and present teaching points to help make the correct diagnosis. It is important for radiologists to be aware of the common and rare etiologies of skull lesions as well as the clinical and imaging characteristics which can be used to develop an accurate differential to ensure a timely diagnosis and initiate appropriate management.

An algorithmic clinicoradiological approach to paediatric cranial vault lesions: distinguishing normal variants from pathologies.

Lesions of the paediatric cranial vault are diverse both in their presentation and aetiology. As such, they pose a diagnostic challenge to the paediatric neurosurgeon and neuroradiologist. In this article, we delineate the spectrum of paediatric calvarial pathology into four distinct groups: (1) lytic lesion(s); (2) focal sclerotic lesion(s); (3) diffuse cranial vault sclerosis; and (4) abnormal shape of the cranial vault. It is our aim that this more pragmatic, algorithmic approach may mitigate diagnostic uncertainty and aid the more accurate diagnosis of paediatric calvarial lesions.

Innumerable Meningiomas Arising in a Patient With Tuberous Sclerosis Complex Decades After Radiation Therapy.

Meningioma is the most common radiation-induced brain neoplasm, usually occurring after a latency of 20 - 35 years, with multiplicity in 10% of cases. Radiation-induced meningiomas (RIMs) have not previously been reported in patients with tuberous sclerosis complex (TSC), unlike their well-known occurrence in other familial tumor predisposition syndrome patients. We report a TSC patient who developed numerous intracranial meningiomas twenty five year after radiation therapy for subependymal giant cell astrocytoma (SEGA). Autopsy examination showed innumerable, coalescent, benign, meningothelial meningiomas, WHO grade 1, ranging in size from 0.2 cm to 3.3 cm. Autopsy also showed small residual SEGA, radiation-induced cerebral vasculopathy, and classic TSC features including several small subependymal nodules ("candle gutterings"), white matter radial heterotopia, facial angiofibromas, dental enamel pitting, one ash leaf spot, and multiple hepatic and renal angiomyolipomas. Next-generation sequencing analysis utilizing a 500+ gene cancer panel demonstrated chromosomal loss involving the majority of chromosome 22, including the NF2 gene locus, as well as a truncating nonsense mutation in TSC1 p. R509*. While TSC patients rarely require radiation therapy, this striking case suggests that patients with TSC should be monitored closely if cranial therapeutic radiation is administered.

Multimodality characteristics of multifocal choroid plexus carcinoma with bilateral calvarial defects in a dog.

An 8-year-old male intact miniature poodle presented for blindness, obtundation, tetraparesis, and vestibular signs. Magnetic resonance imaging, radiography, and ultrasound revealed a left piriform lobe lesion, right cerebellar and left brainstem lesions, and hydrocephalus and bilateral calvarial defects. Histopathology confirmed a choroid plexus carcinoma with meningeal and intraventricular metastases. The calvarial defect did not show evidence of necrosis, osteoclastic resorption, inflammation or neoplastic infiltration, reflecting a quiescent calvarial atrophy or dysplasia. These novel findings supported inclusion of bone atrophy secondary to chronic increased intracranial pressure as a differential diagnosis for large calvarial defects in dogs with choroid plexus carcinoma.

Relationship between bullet diameter and bullet defect diameter in human calvariums.

Existing literature on the relationship between bullet diameter and bullet defect diameter in the human calvarium is summarized and discussed. The hypothesis, derived from the literature, that bullet deformation influences bullet defect diameter was studied in a small controlled experiment. The mean defect size caused by non-deforming projectiles was found to be smaller than the mean defect size caused by deforming projectiles of equal original mass and size. The p value of the difference between the two means, measured in two different ways, was found to be 0.002 for both in a Mann-Whitney U test and was significant if the confidence level is set at 5%.

Treatment of scalp defects with a combination of trephination and platelet-rich plasma.

In cases of complete scalp loss where the calvarium is exposed and reconstruction cannot be achieved using replantation, or local or far flaps, using trephination to create holes to the depth of the spongeous layer followed by grafting once granulation has covered all defects is an important reconstruction alternative. However, growth of the granulation after trephination and waiting for the entire defect to be covered is a slow process. Since the introduction of platelet-rich plasma (PRP), several researchers have investigated the efficacy of different bone healing and grafting procedures. We present a case with full-thickness partial scalp defect in which we support the development of granulation through holes drilled to the spongeous layer by trephination with PRP.

Dental implants placed in severely atrophic jaws reconstructed with autogenous calvarium, bovine bone mineral, and collagen membranes: A 3- to 19-year retrospective follow-up study.

OBJECTIVES: To present the clinical, radiographic, and patient-related outcomes of patients presenting with severely resorbed ridges reconstructed with autogenous calvarial bone blocks and rehabilitated with implant-supported prostheses. MATERIAL AND METHODS: From 1998 to 2014, 72 patients presenting with severe bone defects were reconstructed with autogenous calvarial bone blocks covered with bovine bone mineral granules and collagen membranes. Four to 9 months later, 330 implants were placed and loaded 3-9 months later. The follow-up ranged from 3 to 19 years (mean: 8.1 years). The following parameters were recorded: (a) complication rate of the reconstructive procedure; (b) bone resorption before implant placement; (c) implant survival rate and implant-related complications; (d) peri-implant bone resorption; and (e) patient's satisfaction inquired with a dedicated questionnaire. RESULTS: No patients developed severe complications, such as complete loss or resorption of the grafts. A dehiscence occurred in six patients, which developed a mild graft resorption. The mean peri-implant bone resorption before implant placement was 0.13 mm (SD ± 0.71). All patients received the planned number of implants. Three patients were lost during the follow-up. The survival rate of implants at the end of the observation period was 98.5%. The mean peri-implant bone resorption ranged from 0.00 to 4.87 mm (mean: 1.11 mm). At last, 90% of the patients were very satisfied as regards the treatment received. CONCLUSIONS: Results from this study suggested that: (a) bone volume in the areas reconstructed with calvarial grafts was stable over time; (b) survival rates of implants were consistent with those reported for implants placed in native bone; (c) patient's satisfaction was high.

Spontaneous evacuation of hyperacute extradural hematoma: two illustrative case reports.

Spontaneous drainage of extradural hematoma (EDH) through a skull fracture is rare, with only 14 cases reported to date. Five of these belong to pediatric age group. The authors report two cases of spontaneous evacuation of acute EDH, in children, with two differing types of skull fractures, one being an elevated fracture. The context, in which the terminologies of "spontaneous evacuation" and "spontaneous resolution" to be used, is clarified.

CALVARIAL OSTEOSARCOMA WITH CEREBRAL COMPRESSION IN A FREE-RANGING POWERFUL OWL (NINOX STRENUA).

A free-ranging powerful owl (Ninox strenua) presented in a dull state with extensive bruising of the skin overlying the skull, due to suspected trauma. Supportive care was provided, which resulted in the return to a normal state, although intermittent subtle neurologic abnormalities remained. One month from original presentation, intermittent episodes of head turning and a possible seizure were noted, but behavior and appetite were otherwise normal. The owl was referred to Taronga Wildlife Hospital for evaluation. On presentation, the owl exhibited severe neurologic abnormalities, prompting euthanasia. At necropsy the dorsum of the skull exhibited marked osseous proliferation, extending ventrally and compressing the cerebrum. The skull was radiographed and submitted for histopathology. A diagnosis of osteoblastic osteosarcoma was made. This is the first report of a calvarial osteosarcoma in a powerful owl.

Parthenolide inhibits polyethylene particle-induced mouse calvarial osteolysis in vivo.

BACKGROUND: Periprosthetic osteolysis and aseptic loosening (AL) after joint arthroplasty are serious problems encountered after an implant surgery. AL is possibly caused by osteolysis or local bone resorption induced by implant-derived wear particles. However, effective treatments for osteoclastic bone resorption and AL mediated by wear particles have not been developed except surgical revision. Therefore, a new strategy should be developed to improve osteolysis associated with AL via pharmacologic intervention. MATERIALS AND METHODS: The effects of parthenolide (PTN), a nuclear factor-kappa B inhibitor and sesquiterpene lactone, on polyethylene particle-induced osteolysis in vivo were investigated using a mouse calvarial model. Bone volume/tissue volume (BV/TV, %), bone surface/bone volume (BS/BV, 1/mm), osteoclast number per bone perimeter (N.Oc/B.Pm, /mm), and eroded surface per bone surface (ES/BS, %) were determined by micro-computed tomography and histologic analyses. RESULTS: Severe bone resorption and rapid osteoclast formation were found in the cranium of the subjects after polyethylene particles were implanted. ES/BS (P < 0.001), N.Oc/B.Pm (group III, P < 0.05; group IV, P < 0.001), and BS/BV (P < 0.001) increased compared with those in group II; BS/BV (P < 0.001) decreased in group II but was improved in groups III and IV, which were treated with PTN. No significant difference in these parameters was observed among groups I, III, and IV. CONCLUSIONS: PTN possibly elicited therapeutic effects on osteolysis induced by wear particles, indicating that PTN could be used as a therapeutic agent of AL induced by wear particles.

The management of non-melanocytic skin malignancies of the scalp and calvarium.

BACKGROUND: The management of advanced cutaneous malignancies has been controversial. Thirteen patients with nonmelanoma skin neoplasias that had invaded the bone of the calvarium and scalp were treated in our centre. OBJECTIVE: The purpose of this study was to evaluate our experience in treating these malignancies with scalp resection and full or partial thickness cranium reconstruction. PATIENTS AND METHODS: From June 2008 to March 2012, thirteen patients with locally advanced tumours of the scalp invading the calvarium were treated with wide local excision of the scalp combined with an underlying craniectomy and dural resection if needed. RESULTS: Using histopathological diagnosis eleven patients were diagnosed with basal cell carcinoma and two patients with squamous cell carcinoma. A full thickness cranium resection was performed in seven patients and partial in six patients. CONCLUSION: These large cancers occasionally invade adjacent structures, as well as bone, presenting a challenging surgical problem. In general, giant rotational or island scalp flaps and free tissue transfers are needed to close the area. Finding clean margins are an important part of treating patients with bone involvement and can usually be attained using outer tabula curettage thus preventing unnecessary morbidity.

Comparing the effects of Bone+B® xenograft and InterOss® xenograft bone material on rabbit calvaria bone defect regeneration.

BACKGROUND: The bone regeneration therapy is often used in patients with inadequate bone support for implants, particularly following tooth extractions. Xenografts derived from animal tissues are effective bone reconstructive options that resist resorption and pose a low risk of transmitting disease. Therefore, these implants may be a good option for enhancing and stabilizing maxillary sinuses. The purpose of this study was to compare two xenografts, Bone+B® and InterOss®, for the reconstruction of rabbit calvaria defects. METHODS AND MATERIALS: The study involved seven male New Zealand white rabbits. In the surgical procedure, 21 spots were created on both sides of the midline calvarium by creating three 8-millimeter defects. A control group was used, as well as two treatment groups utilizing Bone+B® Grafts and InterOss® Grafts. After 3 months, the rabbits were euthanized, followed by pathological evaluation. Analysis of these samples focused on bone formation, xenograft remaining material, and inflammation levels, using Adobe Photoshop CS 8.0 and SPSS version 24. RESULTS: With the application of Bone+B® graft, bone formation ranged from 32% to 45%, with a mean of 37.80% (±5.63), and the remaining material ranged from 28% to 37%, with a mean of 32.60% (±3.65). Using InterOss® grafts, bone formation was 61% to 75%, the mean was 65.83% (±4.75), and the remaining material was 9% to 18%, with a mean of 13.17% (±3.06). The bone formation in the control group ranged from 10% to 25%, with a mean of 17.17% (±6.11). InterOss® had lower inflammation levels than other groups, but the difference was not statistically significant (p > .05). CONCLUSION: InterOss® bone powder is the best option for maxillofacial surgery and bone reconstruction. This is due to more bone formation, less remaining material, and a lower inflammation level. Compared to the control group, Bone+B® improves healing and bone quality, thus making it an alternative to InterOss®.

An Unusual Presentation of a Primary Chondrosarcoma of the Cranial Vault.

Chondrosarcomas are malignant cartilaginous tumors that usually affect the pelvic bone and long bones. Primary chondrosarcomas of the skull are rare, with the cranial vault being an even more unusual localization. We report a case of a 75-year-old man presenting with headaches and outgrowth of the parietal scalp. CT scan of the head showed an extracranial cystic well-rounded mass originating at the parietal suture and eroding through the adjacent parietal bone. The patient underwent an en bloc surgical resection of the mass, and histological examination confirmed a grade I chondrosarcoma.