PMC6914884_01
A 9 year old FS Dachshund presenting with a large multilobular osteochondrosarcoma.
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Tumor diameter at presentation was 7.2 x 5.2 x 6.7 cm, with an asymmetric placement toward the left side (Figure 1).
3D reconstruction of pre-operative CT and 3D printed biomodel with proposed craniectomy.
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An anatomic bio-model of the patient and tumor was printed using the J750 polyjet 3D printer (Figure 2).
Biomodel in use intra-operatively for planning orbitectomy site.
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With reference to the 3D model, osteotomy of the zygomatic arch was performed to improve orbital access (Figure 3).
3D printed cutting guide in use to mark resection margin.
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Once the tumor margins were exposed, the cutting guide was placed around the tumor and electrocoagulation used to mark the excision margin (Figure 4).
Extent of brain exposure following craniectomy. Stay suture marks descended left eye following zygomatic arch resection and orbitectomy. The medial wall of the orbit was resected to within 5 mm of the optic nerve foramen on the left side.
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Following completion of the craniectomy line, periosteal elevators were used to apply dorsal elevation to the segment and fracture the attachment of the cribriform plate (Figure 5).
Plate contouring was re-checked against the 3D model and patient.
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Contouring was re-checked (Figure 6) and the pre-constructed titanium plate was placed over the defect and secured with four 1.5 mm titanium self-tapping screws.
Intra-operative view following reconstruction and restoration of normal eye position.
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Two 5Fr red rubber tubes were placed through two pre-planned holes in the implant that provided access to the frontal sinuses and exited through the skin to prevent air entrapment in the early postoperative period (Figure 7).
Post-operative CT scan.
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A CT scan was repeated under sedation 14 days postoperatively, and showed good skull defect coverage and alignment of the implant (Figure 8).
Multilobular osteochondrosarcoma regrowth after excision and calvaria replacement with titanium implant. (a) Gross aspect of the brain-plate interface after post-mortem removal of the plate. Note the thin fibrous tissue that was extending through the plate's holes. (b) Section through the entire skull at the level of the frontal cortex, post fixation and decalcification. Note the well-demarcated, intraparenchymal compressive mass (black arrows) with small white foci of bone in the structure, compatible with multilobular osteochondrosarcoma (bar = 1 cm). (c) Subgross photomicrograph of the previous section (b). Note the intraparenchymal growth of the mass, attached to the fibrous tissue starting under the fibrovascular tissue (bar = 1 cm; Hematoxylin and eosin (H&E) stain).
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Suppurative sinusitis (Figure 10(d)) that cultured beta-hemolytic E. coli affected the frontal sinuses that tracked along the fascia around the titanium plate (Figures 9(a) and 10(a)). Cross section of the brain revealed a 1.8 cm intracerebral mass (Figures 9(b) and 9(c)) replacing most of the right frontal cortex, causing localized tissue damage, and significant midline shift.
(a) Inflamed granulation tissue immediately under the titanium plate. Note the moderate, predominantly neutrophilic inflammation (bar = 300 microm; H&E stain). (b) Tapering of the inflammation towards the porcine SIS with lymphoplasmacytic predominance and abundant small caliber blood vessels supporting neovascularization (bar = 300 microm; H&E stain). (c) Porcine SIS with appropriate vascularization and no evidence of inflammation immediately covering the brain (bar = 300 microm; H&E stain). (d) Photomicrograph of sinus epithelium revealing a mild to moderate neutrophilic and lymphoplasmacytic sinusitis (bar = 250 microm; H&E stain). (e) Photomicrograph of the multilobular osteochondrosarcoma at the time of surgical excision, revealing lobules of thick tendrils of spindle cells that are enclosing plump polygonal cells admixed with abundant extracellular eosinophilic matrix, interpreted as osteoid, findings typical of this neoplasm (bar = 250 microm; H&E stain). (f) Photomicrograph of the multilobular osteochondrosarcoma regrowth revealing similar organization as previously noted (Figure 10(e)) with slightly less cellular atypia and more organized lobules (bar = 250 microm; H&E stain).
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Suppurative sinusitis (Figure 10(d)) that cultured beta-hemolytic E. coli affected the frontal sinuses that tracked along the fascia around the titanium plate (Figures 9(a) and 10(a)). Histologically, this inflammation attenuated into a lymphoplasmacytic infiltrate towards the porcine SIS (Figure 10(b)); but the porcine SIS was mostly uninflamed. Neovascularization was noted within the porcine SIS (Figure 10(c)). Histologically, compared to the previous excision (Figure 10(e)), the intracranial regrowth had less cellular atypia and larger, coalescing lobules (Figure 10(f)).