CT-guided percutaneous skull biopsy using a drill-assisted system: Technical report of two cases

Abstract

The OnControl coaxial biopsy system (Vidacare Corporation, Shavano Park, TX) includes an inner diamond-tipped access needle and hollow biopsy needle that engage with a battery-powered hand drill. Herein, we report the use of this novel device to perform two CT-guided percutaneous skull biopsies. Both procedures were performed without complication and facilitated a pathologic diagnosis.

Introduction

Most clinical oncology protocols and treatment guidelines require that histologic specimens be obtained for proof of diagnosis, as well as genetic and/or molecular testing.¹ Percutaneous image-guided biopsy is preferable to open biopsy whenever possible, as the former can often be performed in an outpatient setting under conscious sedation with minimal recovery and risk of complications.² The OnControl coaxial biopsy system (Vidacare Corporation, Shavano Park, TX) includes an inner diamond-tipped access needle and hollow biopsy needle that engage with a lithium battery-powered hand drill (Figure 1). Though initially designed and marketed for bone marrow biopsy, clinical applications have expanded to include percutaneous computed tomography (CT)-guided biopsy of the spine and appendicular skeleton.^3,4 Herein, we report the use of this novel device to perform two CT-guided percutaneous skull biopsies.

Figure 1.

The OnControl system. (a) The reusable, lithium battery-powered hand drill is placed into a sterile cover provided with the needle set. (b) The 12-gauge hollow bone core biopsy needle (white arrowhead) and 12-gauge diamond-tipped access needle (black arrowheads) are placed coaxially through the 10-gauge outer cannula (white arrows). (c) The covered drill engages with the coaxial outer cannula and diamond-tipped access needle.

Case 1

A 51-year-old man with a history of poorly controlled type 2 diabetes mellitus and chronic left foot osteomyelitis on long-term antibiotics presented with a six-week history of progressive difficulty swallowing both solids and liquids. Physical examination revealed hoarse voice and left trapezius muscle atrophy. These findings indicated dysfunction of cranial nerves IX, X, and XI, which localized the lesion to the pars nervosa of the left jugular foramen. CT demonstrated an expansile lesion involving the majority of the skull base and parts of the calvaria (Figure 2(a), (b)). Portions of the lesion contained “ground-glass” matrix characteristic of fibrous dysplasia; however, the presence of a central lytic component coupled with the relative acute onset of symptoms raised concern for sarcomatous transformation. Whole body skeletal scintigraphy performed with ^99mTechnetium methylene diphosphonate (^99mTc MDP) showed corresponding increased activity in the skull base and calvaria, but no other skeletal lesions (Figure 2(c)). Hence, percutaneous biopsy of the lytic component of the skull base lesion was performed for definitive histologic diagnosis.

Figure 2.

A 51-year old man with dysphagia, hoarseness, and left trapezius muscle atrophy. ((a), (b)) Computed tomography (CT) shows extensive expansile abnormality involving the skull base and occipital bones. Components of the calvaria have a “ground-glass” appearance typical of fibrous dysplasia (black asterisks); however, lytic destruction of the skull base raises concern for sarcomatous transformation. Note replacement of the jugular foramen, through which pass cranial nerves IX, X, and XI, with soft tissue that encases the internal carotid artery (white arrowhead) and jugular vein (black arrowhead). (c) Anterior and posterior whole body 99mTechnetium methylene diphosphonate skeletal scintigraphy shows increased uptake in the skull base and calvaria corresponding to the abnormality seen on CT; however, there are no other foci of abnormal uptake in the remainder of the skeleton. ((d), (e)) Prone axial CT images show the tip of the drill-powered coaxial needle gaining purchase in the left occipital bone (black arrow), and the soft tissue biopsy needle (white arrow) extending through the outer cannula (white block arrow) into the lytic component of the skull base lesion.

Written informed consent was obtained prior to the biopsy. The patient was placed prone on the CT table and consciously sedated with intravenous midazolam and fentanyl. The skin overlying the left occipital bone was cleansed with betadine, anesthetized with a 50/50 mixture of 1% lidocaine and 0.25% bupivacaine, and a 5 mm incision was made to accommodate the coaxial biopsy system. Using the handheld drill, the 10-gauge outer cannula and 12-gauge diamond-tipped inner needle were incrementally advanced into the occipital bone. After each increment, CT was performed to document the location and trajectory of the needle. Once the outer cannula of the system was purchased in the occipital bone, the inner needle was removed, and a 16-gauge Achieve soft tissue biopsy needle (CareFusion, San Diego, CA) was placed through the outer cannula into the lytic component of the lesion. Six 2-cm soft tissue core specimens were obtained (Figure 2(c), (d)). The time from skin incision to obtainment of the last soft tissue specimen was 16 minutes. The total sedation time for the procedure was 45 minutes, during which the patient received 200 mcg of fentanyl and 2.5 mg of midazolam. The total dose length product for the procedure was 330 mGy. Histopathologic evaluation of the specimens revealed curvilinear trabeculae of woven bone surrounded by fibroblastic stroma consistent with fibrous dysplasia (Figure 3).

Figure 3.

Fibrous dysplasia histopathology. Hematoxylin and eosin staining of a calvarial specimen shows trabeculae of woven bone (white arrow) interspersed between fibroblastic stroma composed of bland spindle cells (white asterisks). These features are classic for fibrous dysplasia.

Case 2

An 80-year-old woman with a history of left breast ductal carcinoma treated with breast conservation therapy presented with a one-week history of diplopia. Physical examination revealed painless right-sided proptosis and limited ability to elevate her right eye. Magnetic resonance imaging with and without gadolinium contrast enhancement revealed a right extraconal retro-orbital mass (Figure 4(a), (b)). ¹⁸F-fluorodeoxyglucose positron emission tomography (PET)-CT showed increased uptake in the mass as well as a small area in the adjacent left frontal bone (Figure 4(c), (d)). Open biopsy of the retro-orbital mass was performed via a right anterior orbitotomy. Histopathology and immunohistochemical analysis of the open biopsy specimen were consistent with atypical lymphoid hyperplasia of B-cell origin (Figure 5); however, 40% of patients with these lesions develop non-Hodgkin lymphoma.⁵ Consequently, a systemic lymphoma workup was recommended, which prompted a request for percutaneous biopsy of the left frontal bone lesion.

Figure 4.

An 80-year-old woman with painless right proptosis and diplopia. Axial (a) and coronal (b) post-contrast, fat-suppressed, T1-weighted magnetic resonance imaging show an enhancing right extraconal retro-orbital mass (black asterisks). ((c), (d)) Axial ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) shows increased tracer uptake in the right orbital mass (black asterisk) as well as the left frontal bone (white arrowhead). The left frontal bone lesion measures less than 1 cm in the transverse dimension. (e) Axial CT image shows the outer cannula of the drill-powered coaxial biopsy system (white block arrow) purchased in the calvaria and the hollow inner biopsy needle (white arrow) traversing the area of abnormal left frontal bone FDG uptake on PET-CT.

Figure 5.

B-cell lymphoma histopathology. (a) Hematoxylin and eosin staining of a retro-orbital mass open biopsy specimen shows sheets of lymphocytes with irregular nuclei and scant cytoplasm infiltrating adipose and soft tissue consistent with a lymphoproliferative disorder. The majority of these lymphocytes were CD20-positive on immunohistochemistry, suggesting a B-cell origin; however, flow cytometry showed polyclonal B-cell populations. Given the lack of clonality, a diagnosis of atypical lymphoid hyperplasia was made. (b) Hematoxylin and eosin-stained calvarial biopsy shows trabeculae with bone marrow spaces virtually replaced by diffuse cellular infiltrates similar in appearance to those seen in the open biopsy specimen. ((c), (d)) Immunohistochemistry of the calvarial biopsy shows a predominance of the cellular infiltrate is CD20 positive confirming B-cell origin (c), and pan-cytokeratin negative, which rules out a diagnosis of metastatic carcinoma (d). Multi-organ involvement by a lymphoproliferative process of B-cell origin is consistent with a diagnosis of B-cell lymphoma.

Written informed consent was obtained prior to the biopsy. The initial steps were the same as for the first case, except that this patient was placed in the right lateral decubitus position on the CT table and the procedure was performed with the patient under general anesthesia. The 10-gauge outer cannula and 12-gauge diamond-tipped inner access needle were manually advanced until purchase was obtained in the left frontal bone. The inner diamond-tipped needle was then exchanged for the hollow biopsy needle, engaged with the handheld drill, and incrementally advanced into the target area (Figure 4(e)). The trajectory of the needle was checked frequently to ensure that inadvertent overdrilling would not violate the inner table of the calvaria. Seven bone core specimens of 2 to 10 mm were obtained. The time from skin incision to obtainment of the last bone core biopsy was 29 minutes. The total dose length product for the procedure was 1,260 mGy. Histopathologic evaluation showed a lymphoproliferative process of B-cell origin with similar features as those seen in the open biopsy specimen obtained from the retro-orbital mass (Figure 5). Based on the presence of multi-organ involvement, a diagnosis of B-cell lymphoma was made.

Discussion

The cases presented demonstrate that percutaneous skull biopsy is feasible and highlight the advantages of using a coaxial drill-powered technique. First, the coaxial system allows the operator to gain access with the diamond-tipped inner needle, which can then be exchanged for either a soft tissue biopsy needle or hollow bone-coring needle. In both cases the obtained specimens were adequate for histologic evaluation and facilitated pathologic diagnosis.

Second, the ease with which the handheld drill cuts through bone gives the operator greater control over the needle trajectory compared with standard, manual techniques. Manual biopsy needles are advanced through bone with a combination of rotation and forward pressure. The force needed to advance manual needles through sclerotic bone, or even normal bone in young patients, requires the recruitment of proximal arm and shoulder muscles with less fine movement capability. In contrast, the battery-powered drill allows the interventionalist to easily advance the biopsy needle using fine hand and wrist movements, which facilitate accurate targeting of small lesions and avoidance of injury to surrounding structures. In the first case, the soft tissue component of the lesion was targeted for biopsy, because sarcomatous transformation is typically osteolytic.⁶ However, this soft tissue component encased several critical structures, including the internal carotid artery, internal jugular vein, and multiple cranial nerves, and was surrounded by thick sclerotic bone. Nonetheless, the soft tissue component was safely accessed with the patient under conscious sedation only 16 minutes after skin incision (Figure 2). In the second case, the control provided by the drill allowed the hollow biopsy needle to be advanced into a small lesion through the narrow medullary cavity of the left frontal bone without violating the intracranial space (Figure 4).

The case of fibrous dysplasia is also interesting from a diagnostic standpoint. Fibrous dysplasia is a non-neoplastic developmental lesion in which varying ratios of fibrous stroma and woven bone replace and expand the medullary cavity of normal bone.^7,8 The characteristic radiographic appearance of fibrous dysplasia is an expansile osseous lesion with “ground-glass” matrix.^7,9 However, the appearance in this case of a predominantly lytic central component surrounded by dense sclerotic bone is seen in 11% of cases¹⁰ (Figure 2). Craniofacial fibrous dysplasia is most often asymptomatic, but expansile enlargement of the bones comprising the skull base can cause blindness, hearing loss, and other cranial nerve palsies.^11,12 Additionally, fibrous dysplasia can undergo acute cystic degeneration leading to a sudden increase in size of a previously stable lesion and acute clinical symptoms. This phenomenon best explains the clinical presentation of our patient, the lytic central component of the lesion on CT, and benign histologic findings. However, biopsy was necessary to exclude sarcomatous transformation, which occurs in 0.4% to 4% of cases, and similarly presents with acute symptom onset and new osteolysis on CT.⁶

Conclusion

Percutaneous skull biopsy is feasible and facilitated by a coaxial, drill-powered biopsy device.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

Declaration of conflicting interest

JW Jennings is a speaker panelist and consultant for DFINE Inc. The other authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.