Calvarial and skull base metastases: expanding the clinical utility of Gamma Knife surgery

Practical Guideline for Prevention of Patchy Hair Loss following CyberKnife Stereotactic Radiosurgery for Calvarial or Scalp Tumors: Retrospective Analysis of a Single Institution Experience

INTRODUCTION

Patchy alopecia is a common adverse effect of stereotactic radiosurgery (SRS) on the calvarium and/or scalp, yet no guidelines exist for its prevention. This study aims to investigate the incidence and outcomes of patchy alopecia following SRS for patients with calvarial or scalp lesions and establish preventive guidelines.

METHODS

The study included 20 patients who underwent CyberKnife SRS for calvarial or scalp lesions, resulting in a total of 30 treated lesions. SRS was administered as a single fraction for 8 lesions and hypofractionated for 22 lesions. The median SRS target volume was 9.85 cc (range: 0.81-110.7 cc), and the median prescription dose was 27 Gy (range: 16-40 Gy), delivered in 1-5 fractions (median: 3). The median follow-up was 15 months.

RESULTS

Among the 30 treated lesions, 11 led to patchy alopecia, while 19 did not. All cases of alopecia resolved within 12 months, and no patients experienced other adverse radiation effects. Lesions resulting in alopecia exhibited significantly higher biologically effective dose (BED) and single-fraction equivalent dose (SFED) on the overlying scalp compared to those without alopecia. Patients with BED and SFED exceeding 60 Gy and 20 Gy, respectively, were 9.3 times more likely to experience patchy alopecia than those with lower doses. The 1-year local tumor control rate for the treated lesions was 93.3%. Chemotherapy was administered for 26 lesions, with 11 lesions receiving radiosensitizing agents. However, no statistically significant difference was found.

CONCLUSION

In summary, SRS is a safe and effective treatment for patients with calvarial/scalp masses regarding patchy alopecia near the treated area. Limiting the BED under 60 Gy and SFED under 20 Gy for the overlying scalp can help prevent patchy alopecia during SRS treatment of the calvarial/scalp mass. Clinicians can use this information to inform patients about the risk of alopecia and the contributing factors.

Revisiting the Role of Surgical Resection for Brain Metastasis

Brain metastasis (BM) is the most common type of brain tumor in adults. The contemporary management of BM remains challenging. Advancements in systemic cancer treatment have increased the survival of patients with cancer. Although the treatment of BM is still complicated, advances in radiotherapy, including stereotactic radiosurgery and chemotherapy, have improved treatment outcomes. Surgical resection is the traditional treatment for BM and its role in the surgical resection of BM has been well established. However, refinement of the surgical resection technique and strategy for BM is needed. Herein, we discuss the evolving role of surgery in patients with BM and the future of BM treatment.

Gamma Knife Radiosurgery as a Salvage Treatment for Nasopharyngeal Carcinoma with Skull Base and Intracranial Invasion (T4b)

It is usually difficult to achieve good outcomes with salvage treatment for recurrent nasopharyngeal carcinoma (NPC) because of its deep-seated location, surrounding critical structures, and patient history of high-dose irradiation. Gamma Knife radiosurgery (GKS) is a treatment option for malignancies with skull base and intracranial invasion. We conducted a retrospective, observational, single-center study including 15 patients with recurrent NPC (stage T4b) involving the skull base and intracranial invasion, who underwent GKS as a salvage treatment. Patients were enrolled over 12 years. Per a previous study, the TNM classification T4b was subclassified into T4b1 and T4b2, defined as the involvement of the skull base or cavernous sinus with an intracranial extension of <5 mm and >5 mm, respectively. The effect of prognostic factors, including age, sex, survival period, magnetic resonance imaging (MRI) presentation, presence of other distant metastases, tumor volume, marginal dose, maximal dose, and Karnofsky Performance Status (KPS), on outcomes was analyzed. The patients with T4b1 NPC (p = 0.041), small tumor volume (p = 0.012), higher KPS (p < 0.001), and no other metastasis (p = 0.007) had better outcomes after GKS treatment, suggesting that it is a viable treatment modality for NPC. We also suggest that detailed brain imaging studies may enable the early detection of intracranial invasion.

Skull metastases and osseous venous malformations: The role of diffusion-weighted and dynamic contrast-enhanced MRI

BACKGROUND AND PURPOSE

Skull metastasis (SM) is a common secondary malignancy. We evaluated the diagnostic performance of diffusion-weighted imaging (DWI) and dynamic contrast-enhanced magnetic resonance imaging (MRI) in differentiating SM from osseous venous malformations and SM of various origins.

METHODS

This study included 31 patients with SM (median age, 64 years; range, 41-87 years; 29 women; 24 and 7 patients with breast and non-small cell lung cancer, respectively) and 16 with osseous venous malformations (median age, 68 years; range, 20-81 years; 10 women) who underwent both DWI and dynamic contrast-enhanced MRI between January 2015 and October 2021. Normalized mean apparent diffusion coefficients (ADCs) and dynamic contrast-enhanced MRI parameters were compared between SM and osseous venous malformations, and between breast cancer and non-small cell lung cancer. Multivariate stepwise logistic regression analyses were performed to identify statistically significant parameters.

RESULTS

Plasma volume and time-to-maximum enhancement were the most statistically significant parameters for differentiating SM from osseous venous malformations, with an area under the receiver operating characteristic curve of 0.962. The normalized mean ADC and peak enhancement values were the most statistically significant parameters for differentiating breast cancer from non-small cell lung cancer, with an area under the curve of 0.924.

CONCLUSIONS

Our results highlight the efficacious diagnostic performance of DWI and dynamic contrast-enhanced MRI in distinguishing SM from osseous venous malformations and differentiating SM of various origins.

Varied Clinical Presentation and Management of Calvarial Metastases

Calvarium and skull base can be affected by a variety of benign, tumor-like, and malignant processes. Skull metastases (SMs) may be located in any layer of the skull and may be incidental or present with neurological symptoms during the diagnostic workup. In the present study, we discuss the occurrence of SMs from various index malignancies and their myriad clinical presentation. This data-based study includes patients of bone metastases between June 2018 and July 2020. Patients with skull bone metastases were recognized, and location of primary site, their clinical presentation, and management strategy were noted. Ten patients with skull bone metastases were identified during this period. Four patients had skull base location with clinical manifestation as syndromes. Six patients had primary from breast cancer, three from Ewing's sarcoma, and one from lung cancer. Management varied according to the primary site and symptoms of each patient. SM, though not rare, is often diagnosed incidentally but presents diagnostic and management challenges in the patient with cancer.

Full-Thickness Craniodural Metastasis with Leptomeningeal Infiltration of Salivary Origin: A Radiological Lesson and a Technical Remark

Calvarial metastases are a relatively rare entity, with an overall incidence of 3-4%. Among these cases, metastases arising from salivary gland cancers are even rarer; in fact, large studies regarding salivary gland tumors showed that brain metastases are observed in 0.8% of the cases. Generally, bone metastases have been described in proximity to primary tumors, while bloodstream-disseminated lesions are often located inside the brain parenchyma. During every surgical step, traction on lower-lying infiltrated tissues must be avoided in order to successfully remove the lesion. This case report presents the first ever case of a 67-year-old woman affected by submandibular gland undifferentiated adenocarcinoma metastasis with a full-thickness involvement of the calvarium, pachy- and leptomeninges.

A rare case of calvarial tuberculosis from the Avar Age (8th century CE) cemetery of Kaba-Bitózug (Hajdú-Bihar county, Hungary) - Pathogenesis and differential diagnostic aspects

The aim of our paper is to present and discuss in detail the bony changes indicative of tuberculosis (TB) that were identified in a skeleton (KB67), unearthed from grave 67 of the 8th-century-CE cemetery of Kaba-Bitózug (Hungary). Furthermore, to provide the differential diagnoses of the observed alterations, with special attention to the cranial osteolytic lesions. During the macro- and micromorphological examinations of KB67, the skull revealed three small, well-circumscribed, punched-out osteolytic lesions accompanied by endocranial granular impressions, abnormal blood vessel impressions, periosteal appositions, and cortical erosion. The postcranial skeleton exhibited osteolytic lesions, cortical remodelling and erosion, and signs of hypervascularisation in the spine. Based on the differential diagnosis of the cranial osteolytic lesions and their co-occurrence with endocranial and vertebral bony changes indicative of TB, they most likely resulted from tuberculous involvement of the frontal and left parietal bones. The morphologically established diagnosis was confirmed by a PCR analysis that provided evidence for the presence of Mycobacterium tuberculosis DNA in KB67. KB67, the first reported archaeological case with calvarial TB from the present-day territory of Hungary, gives us a unique insight into the occurrence of a rare manifestation of TB in the Avar Age of the Great Plain.

Skull Base Metastasis from Hepatocellular Carcinoma: Clinical Presentation and Efficacy of Radiotherapy

Purpose

Skull base metastasis (SBM) from hepatocellular carcinoma (HCC) presents detrimental survival outcomes with cranial nerve symptoms; however, they have received little attention. This study aimed to investigate the clinical presentation and efficacy of radiation therapy (RT) in patients with SBM from HCC.

Patients and Methods

We identified patients with SBM from HCC in Yonsei Cancer Center from 2005 to 2019. Image evaluations and SBM-related symptoms were reviewed. Overall survival was calculated using the Kaplan–Meier method and compared through the Log rank test. The oligometastasis group included patients with less than five foci of tumors, while the extensive metastasis group presented five or more sites.

Results

The incidence of SBM from HCC was 1.5% (58/3793 patients), commonly found in the middle cranial fossa. SBM associated symptoms presented in 51 patients, and the most common were head and neck area pain, and orbital symptoms, The palliation rate after RT was 65% (24/39 patients) for overall symptoms and 83.3% (20/24 patients) for cranial nerve symptoms. In whole cohort, overall survival was analyzed, and the median overall survival of patients with oligometastasis was better than extensive metastasis (23.7 months vs 1.8 months, p < 0.001). In subgroup who received RT (39 patients), the median overall survival was 23.7 and 2.7 months for patients with oligo and extensive metastasis, respectively (p < 0.001).

Conclusion

This study confirmed clinical features of SBM from HCC. Overall survival was generally poor, but patients presenting oligometastasis seemed to have possibility of relative long-term survival. Although radiation was effective in SBM-induced symptom relief, dose–response relationship in local control rate and overall survival needs further studies with larger number of patients.

Solitary Calvarial Metastasis As the First Presentation of Urothelial Bladder Cancer

The most common sites of metastasis from urothelial carcinoma of the bladder include the lymph nodes, bones, lungs, liver, and peritoneum. Bladder carcinoma metastases of the head are uncommon. In the English literature, only a few cases of bladder carcinoma metastasis to the skull base have been reported, and no cases of metastasis to the calvaria have been reported previously. We present the first case of calvarial metastasis from bladder carcinoma that preceded the diagnosis of the primary tumor. Bladder calvarial metastasis as the first evidence of a primary tumor is a rare event and a sign of an advanced stage of the disease. Therefore, adequate staging is essential to ensure appropriate treatment. Surgical treatment of calvarial injuries is usually secure.

Calvarial lesions: overview of imaging features and neurosurgical management

Calvarial lesions are rare and can present as a variety of different diseases. The lesions can be palpable on the skin and cause local pain and paraesthesia and, depending on the location, neurological deficits can also occur. This research aims to present an overview of typical imaging features as well as neurosurgical management. We examined the charts of patients who underwent surgery on a calvarial lesion in our department between 2004 and 2017 (n=133). Retrospectively, the pre-, intra-, and postoperative data were analyzed with morphological and histological findings and compared with each other. Pain, swelling, cosmetically disturbing, and neurological deficits were the main complaints. Seventy-seven lesions were limited to the bone, while another 56 lesions showed an infiltrating growth in the adjacent tissue. Depending on the clinical signs and suspected diagnosis, a biopsy, a partial removal, or a complete resection was performed. Histiocytosis (n=20), meningiomas (n=20), metastases (n=19), and osteomas (n=16) were the most common lesions. Fibrous dysplasia (n=6) and intraosseous hemangioma (n=9) were less common; other lesions were present only in isolated cases. Imaging features may suggest the lesion to be benign or malignant, but the diagnosis can be only confirmed by histological examination. The surgical strategy depends on the complaints, location of the lesion, and suspected diagnosis. Adjuvant treatment should be initiated according to the histological findings.

Cranial nerve palsy caused by metastasis to the skull base in patients with castration-resistant prostate cancer: Three case reports

INTRODUCTION

Skull base metastasis of prostate cancer associated with cranial nerve palsy is rare. We observed three patients with aggressive prostate cancer who experienced cranial nerve palsy.

CASE PRESENTATION

Case 1 was a 53-year-old patient who was treated with carboplatin and etoposide. He noticed sensory abnormalities on his left mouth edge. Head magnetic resonance imaging revealed skull base metastasis. Case 2 was a 50-year-old patient who received docetaxel. This patient exhibited ptosis of the left eye. Skull base metastasis was detected by magnetic resonance imaging. External beam radiation therapy was performed. Case 3 was a 64-year-old patient who was treated with docetaxel. He experienced ptosis of the right eye and diplopia. He was also treated with external beam radiation therapy.

CONCLUSION

External beam radiation therapy exhibited some efficacy against the symptoms, but skull base metastasis of treatment-resistant prostate cancer has poor prognosis. Three patients died within 3 months after symptoms occurred with or without external beam radiation therapy.

Skull Base Metastasis of Breast Cancer With Oculomotor and Trochlear Nerve Palsy

Skull base metastatic tumors are rare. Breast cancer in particular can cause bone metastases after a long period of time. A 70-year-old woman presented with multiple cranial nerve palsy. Magnetic resonance imaging revealed a lesion that extended from the orbit to the base of the skull, and the patient was referred to our department. Ophthalmological evaluation showed left visual acuity impairment, left oculomotor nerve palsy, and left trochlear nerve palsy. Endoscopic biopsy performed 5 years after the completion of breast cancer treatment revealed skull base metastases. In unilateral multiple cranial nerve palsy, the possibility of skull base metastases should be considered.

Bone metastases in thyroid cancer

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Osseous metastases (OMs) occur in only 4% of all thyroid cancer patients but are associated with greatly increased morbidity and mortality.

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OMs are about twice as frequent in follicular, hurthle cell, and medullary thyroid cancers as compared to papillary thyroid cancers.

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OMs are often lytic, triggered via activation of osteoclasts by tumor cells in a “vicious cycle”.

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OMs are often initially asymptomatic, but associated with eventual skeletal related events in >75%.

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Early identification of OMs, preemptive treatment with antiresorptive agents, and aggressive treatment of focal lesions before crisis are key.

Whereas preemptive screening for the presence of lymph node and lung metastases is standard-of-care in thyroid cancer patients, bone metastases are less well studied and are often neglected in thyroid cancer patient surveillance. Bone metastases in thyroid cancer are, however, independently associated with poor/worse prognosis with a median overall survival from detection of only 4 years despite an otherwise excellent prognosis for the vast majority of thyroid cancer patients. In this review we summarize the state of current knowledge as pertinent to bony metastatic disease in thyroid cancer, including clinical implications, impacts on patient function and quality of life, pathogenesis, and therapeutic opportunities, proposing approaches to patient care accordingly. In particular, bone metastasis pathogenesis appears to reflect cooperatively between cancer and the bone microenvironment creating a “vicious cycle” of bone destruction rather than due exclusively to tumor invasion into bone. Additionally, bone metastases are more frequent in follicular and medullary thyroid cancers, requiring closer bone surveillance in patients with these histologies. Emerging data also suggest that treatments such as multikinase inhibitors (MKIs) can be less effective in controlling bone, as opposed to other (e.g. lung), metastases in thyroid cancers, making special attention to bone critical even in the setting of active MKI therapy. Although locoregional therapies including surgery, radiotherapy and ablation play important roles in palliation, antiresorptive agents including bisphosphonates and denosumab appear individually to delay and/or lessen skeletal morbidity and complications, with dosing frequency of every 3 months appearing optimal; their early application should therefore be strongly considered.

Successful Treatment of Anal Canal Cancer Metastasis to the Cranial Bones: A Case Report and Literature Review

Single metastasis to the cranial bone represents a very uncommon occurrence that can arise from an anal canal cancer. No cases of cranial bone metastasis from anal canal carcinoma are available in the literature. Herein, we present a case of a unique metastatic lesion to the right parietal bone that occurred after curative chemoradiotherapy of primary squamous cell anal canal carcinoma. The patient received radiotherapy and systemic platinum-based chemotherapy, with optimal local control, high compliance and a well tolerable level of toxicity.

Symptomatic Meckel's Cave Metastasis from Castration-resistant Prostate Cancer Treated with Gamma Knife Radiosurgery

Prostate cancer commonly spreads to the axial and appendicular skeleton, but metastases to the brain parenchyma or skull base are uncommon. In the cases that this happens, the symptoms are usually associated with disease involving the orbit. Metastasis to the Meckel’s cave causing trigeminal nerve palsy is an exceedingly rare entity. We are presenting a case of this in a man with metastatic castration-resistant prostate cancer. Metastatic prostate cancer to the Meckel's cave is extremely uncommon, and there is no standard of care. Radiation therapy, especially radiosurgery, is increasingly recognized as an excellent alternative to surgery for lesions in the Meckel’s cave and intracranial/skull base prostate cancer metastases. Gamma Knife radiosurgery (Elekta, Stockholm, Sweden), in particular, has been reported to achieve local control close to 90% for calvarial and skull base metastases with few side effects and requires only one treatment. Our patient’s 1.4 x 1.0 x 1.3 cm metastatic prostate cancer lesion in the Meckel's cave was treated with Gamma Knife to 22 Gy with good treatment response including rapid improvement in his symptoms and no side effects. We review the scarce literature documenting cases of prostate cancer metastatic to the brain or skull base and the only two other documented cases of prostate cancer metastasis the Meckel’s cave neither of which was treated with radiotherapy.

Intracranial dural, calvarial, and skull base metastases

Metastatic disease to the intracranial dura, the calvarium, and the skull base is relatively uncommon but presents unique diagnostic and management challenges in the patient with cancer. Modern imaging techniques have facilitated the detection of intracranial tumor deposits, leading to increased incidence. While dural and calvarial metastases often present with nonspecific symptoms, skull base metastases present with distinct clinical syndromes dependent on the local neurovascular structures affected. Intracranial dural metastases can often be confused with meningioma and pose a diagnostic challenge, as well as significant neurologic morbidity, especially in the setting of hemorrhage. Surgical intervention may be helpful in selected patients for symptomatic relief as well as survival benefit. Management paradigms need to take into account the relative risks, benefits, and likely outcomes for each possible modality of treatment. Surgical excision is useful in many patients and in combination with radiation therapy can provide significant palliation. While medical therapy is rarely an initial therapy in these entities, it may be of added benefit dependent on the underlying tumor histology and prior treatment history. Occasionally treatment with curative intent is justified.

Lung carcinoma presenting as a solitary, painless frontal bone lump

A 50-year-old patient, a smoker, was admitted to the hospital, with a solitary scalp lump. Subcutaneous lumps of the scalp are common but usually benign; however, the painless lump in our patient turned out to be a malignant osteolytic lesion of the skull. Frontal bone was involved, and the disease had spread to the dura. Neuroimaging showed osteolytic lesions involving the axial skeleton, skull and several vertebrae. MRI showed the involvement of the second cervical vertebra, which prompted us to start treatment with dexamethasone. Since the spinal cord was not involved, Oncologists decided not to start radiotherapy treatment until we had reached the final diagnosis. A frontal bone biopsy confirmed the diagnosis of lung carcinoma. Chest X-ray did not identify the pulmonary nodule, but CT scan revealed a 1 cm peripheral, spiculated, pulmonary nodule within a pathological parenchyma (severe diffuse pulmonary emphysema).

Metastatic Renal Cell Carcinoma Mimicking Trigeminal Schwannoma in a Patient Presenting with Trigeminal Neuralgia

We present an unusual case of a metastatic renal cell carcinoma (RCC) mimicking trigeminal schwannoma. The patient, with no prior history of RCC, presented with clinical symptoms and imaging consistent with trigeminal neuralgia secondary to trigeminal schwannoma. Magnetic resonance imaging of the brain showed a large bilobed cystic/solid mass primarily in the cerebellopontine angle cistern, with extension into the left middle cranial fossa, Meckel cave, and left cavernous sinus. Following surgical excision, histopathology revealed the tumor to be an RCC infiltrating into the trigeminal nerve fascicles. Further imaging and investigation revealed widespread metastasis to the vertebral bodies and long bones. Metastatic RCC to the trigeminal nerve is rare. Despite the development of more effective treatment modalities, the prognosis of metastatic RCC remains poor. To our knowledge, this is the first reported case of RCC metastasizing to the trigeminal nerve fascicles.