Solitary Skull Metastasis as Initial Manifestation of Hepatocellular Carcinoma – A Case Report

Metastatic spread of tumors to the skull is quite unusual and often represents diagnostic and therapeutic issues. Skull involvement can be observed in various neoplasms of epithelial origin and are most often due to lung, breast, thyroid, kidney and prostate cancers. However, skull metastases from hepatocellular carcinoma (HCC) have been rarely reported. The prognosis for patients with hepatocellular carcinoma is so poor that treatment of such distant metastatic lesion cannot be achieved before death occurs due to the primary malignancy. Therefore, the clinical manifestations of cranial metastasis prior to that of primary hepatocellular carcinoma have rarely been reported. This case illustrates a rare case of skull metastasis as an initial manifestation of hepatocellular carcinoma. Although a solitary skull metastasis prior to the diagnosis of HCC demonstrates rare metastatic behavior for HCC, especially in Asia, skull metastases from HCC should be included in the differential diagnosis of skull tumors, even if the patient is asymptomatic of liver cirrhosis.

MRI-Based Proton Treatment Planning for Base of Skull Tumors

Purpose: To introduce a novel, deep-learning method to generate synthetic computed tomography (SCT) scans for proton treatment planning and evaluate its efficacy. Materials and Methods: 50 Patients with base of skull tumors were divided into 2 nonoverlapping training and study cohorts. Computed tomography and magnetic resonance imaging pairs for patients in the training cohort were used for training our novel 3-dimensional generative adversarial network (cycleGAN) algorithm. Upon completion of the training phase, SCT scans for patients in the study cohort were predicted based on their magnetic resonance images only. The SCT scans obtained were compared against the corresponding original planning computed tomography scans as the ground truth, and mean absolute errors (in Hounsfield units [HU]) and normalized cross-correlations were calculated. Proton plans of 45 Gy in 25 fractions with 2 beams per plan were generated for the patients based on their planning computed tomographies and recalculated on SCT scans. Dose-volume histogram endpoints were compared. A γ-index analysis along 3 cardinal planes intercepting at the isocenter was performed. Proton distal range along each beam was calculated. Results: Image quality metrics show agreement between the generated SCT scans and the ground truth with mean absolute error values ranging from 38.65 to 65.12 HU and an average of 54.55 ± 6.81 HU and a normalized cross-correlation average of 0.96 ± 0.01. The dosimetric evaluation showed no statistically significant differences (p > 0.05) within planning target volumes for dose-volume histogram endpoints and other metrics studied, with the exception of the dose covering 95% of the target volume, with a relative difference of 0.47%. The γ-index analysis showed an average passing rate of 98% with a 10% threshold and 2% and 2-mm criteria. Proton ranges of 48 of 50 beams (96%) in this study were within clinical tolerance adopted by 4 institutions. Conclusions: This study shows our method is capable of generating SCT scans with acceptable image quality, dose distribution agreement, and proton distal range compared with the ground truth. Our results set a promising approach for magnetic resonance imaging–based proton treatment planning.

Schedule feasibility and workflow for additive manufacturing of titanium plates for cranioplasty reconstruction in canine skull tumors

Additive manufacturing has allowed for the creation of a patient-specific custom solution that can resolve many of the limitations previously reported for canine cranioplasty. The purpose of this pilot study was to determine the schedule feasibility and workflow in manufacturing patient-specific titanium implants for canines undergoing cranioplasty immediately following craniectomy. Computed tomography scans from patients with tumors of the skull were considered and 3 cases were selected. Images were imported into OsiriX MD image processing software and tumor margins were determined based on agreement between a board-certified veterinary radiologist and veterinary surgical oncologist. Virtual surgical planning was performed and a 5mm bone margin was selected. A defect was created to simulate the intraoperative defect. Stereolithography format files of the skulls were imported into Renishaw Additive-manufacture for Design-led Efficient Patient Treatment (ADEPT) software. In collaboration with medical solution center, Additive Design in Surgical Solutions (ADEISS), a custom titanium plate was designed with the input of an applications engineer and veterinary surgical oncologist. Plates were printed in titanium and postprocessed at ADEISS. Total planning time was approximately 2 hours with a manufacturing time of 2 weeks. Based on the findings of this study, with access to an advanced 3D metal printing medical solution center that can provide advanced software and printing, patient-specific additive manufactured titanium implants can be planned, created, processed, shipped and sterilized for patient use within a 3-week turnaround.

Schedule feasibility and workflow for additive manufacturing of titanium plates for cranioplasty reconstruction in canine skull tumors

Additive manufacturing has allowed for the creation of a patient-specific custom solution that can resolve many of the limitations previously reported for canine cranioplasty. The purpose of this pilot study was to determine the schedule feasibility and workflow in manufacturing patient-specific titanium implants for canines undergoing cranioplasty immediately following craniectomy. Computed tomography scans from patients with tumors of the skull were considered and 3 cases were selected. Images were imported into OsiriX MD image processing software and tumor margins were determined based on agreement between a board-certified veterinary radiologist and veterinary surgical oncologist. Virtual surgical planning was performed and a 5mm bone margin was selected. A defect was created to simulate the intraoperative defect. Stereolithography format files of the skulls were imported into Renishaw Additive-manufacture for Design-led Efficient Patient Treatment (ADEPT) software. In collaboration with medical solution center, Additive Design in Surgical Solutions (ADEISS), a custom titanium plate was designed with the input of an applications engineer and veterinary surgical oncologist. Plates were printed in titanium and postprocessed at ADEISS. Total planning time was approximately 2 hours with a manufacturing time of 2 weeks. Based on the findings of this study, with access to an advanced 3D metal printing medical solution center that can provide advanced software and printing, patient-specific additive manufactured titanium implants can be planned, created, processed, shipped and sterilized for patient use within a 3-week turnaround.

Skull Tumors

The diagnostic and treatment approach for patients with skull lesions begins with a thorough history and physical and careful attention to anatomic localization. The patient’s history and exam findings can inform a preliminary differential diagnosis, which may be broadly divided into benign and malignant processes. Based on a preliminary assessment, appropriate neuro-imaging involving magnetic resonance, computed tomograph, and/or vascular modalities may be pursued. Characteristic image findings may further refine a differential. While conservative management may be indicated for the most assuredly benign lesions, surgery is appropriate for cases involving compression of neural structures, deformity, pain or when a tissue diagnosis is required.