PMC6746161_01
(a) Bone scintigraphy demonstrating multiple areas of abnormal uptake, including the left humerus, distal bilateral femur, distal bilateral tibia, thoracic vertebra, and multiple ribs. (b, c) Positron emission tomography/computed tomography (PET/CT) showing increased uptake at the left humerus. (d) OctreoScan revealing increased uptake at the left humerus as with PET/CT.
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PET/CT), and somatostatin receptor-based functional scans (OctreoScan ) identified the suspected causative lesion of TIO in the left humerus (Figure 1). Plain radiographs showed a varus deformity of the humerus and a slightly osteolytic lesion with endosteal scalloping in the diaphysis of the humerus (Figure 2).
Preoperative radiograph of the left humerus ((a) anteroposterior view; (b) lateral view) showing varus deformity at the healed fracture site and osteolytic lesion with endosteal scalloping at the diaphysis.
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PET/CT), and somatostatin receptor-based functional scans (OctreoScan ) identified the suspected causative lesion of TIO in the left humerus (Figure 1). Plain radiographs showed a varus deformity of the humerus and a slightly osteolytic lesion with endosteal scalloping in the diaphysis of the humerus (Figure 2).
(a) Computed tomography of the left humerus showing ((b) upper line level of sagittal view) partial cortical destruction (yellow arrow) and ((c) lower line level of sagittal view) erosion (yellow arrow). (d) T2-weighted fat suppression magnetic resonance image (MRI) of the left humerus showing longitudinal invasion of the tumor, a nearly 7 cm extent in the diaphysis. Axial view of T2-weighted fat suppression of MRI revealing tumor invasion to the (e) extracortical lesion (yellow arrow) and (f) intracortical lesion (yellow arrow).
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Left humerus computed tomography showed partial cortical erosion and destruction (Figure 3(a)-3(c)). Left humerus magnetic resonance imaging (MRI) scans revealed a nearly 7 cm sized lesion in the diaphysis with intracortical and extracortical lesions but without soft tissue dissemination (Figure 3(d)-3(f)).
Intraoperative findings. (a) Extracortical lesion observed. (b) One-sided osteotomy 1 cm apart from the proximal end of the tumor. (c) Isolation from other surgical areas with drapes. (d) Pedicle freeing. (e) Wrapping the humerus after internal fixation and resuturing the deltoid muscle, pectoralis major, biceps, and triceps.
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Muscles attached to the humerus, including the deltoid, were detached from the humerus, and the well-demarcated extracortical tumor was identified at the anterior aspect of the humerus continuing to the medullary cavity (Figure 4(a)). Instead of two-sided osteotomy of the humerus, we osteotomized the proximal portion of the humerus with a 1 cm margin from the tumor in the medullary cavity, preserved the radial nerve, and detached muscles without extended soft tissue resection from the humerus with a 6 cm safety margin from the distal end of the tumor to prevent normal soft tissue freezing (Figure 4(b)). The humerus, including the tumor and the 1 cm margin, was isolated from other surgical areas with drapes (Figure 4(c)). The proximal humerus with a 1 cm margin from the distal end of the tumor was frozen in liquid nitrogen for 20 minutes while replenishing the liquid nitrogen repeatedly (Figure 4(d)) followed by defrosting at room temperature for 15 minutes and in distilled water for 10 minutes. Detached muscles, including the deltoid muscle, triceps medialis, and pectoralis major, were sutured to the polypropylene mesh wrapping the humerus (Figure 4(e)).
(a) Postoperative radiograph of the left humerus representing internal fixation of the osteotomy site after correction of varus deformity using an intramedullary nail. (b) Postoperative CT at 8 months revealing bone union at the osteotomy site.
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The proximal portion of the humerus was osteotomized obliquely to correct the alignment of the humerus and fixed with an intramedullary nail with autologous bone grafting from the ilium, filling the bone defect and enhancing bone healing (Figure 5(a)). Back-out of the locking screw inserted in the humeral head was observed two months after the surgery; however, bone union was observed at 8 months (Figure 5(b)).
Histopathology of the tumor. (a) The tumor was composed of sheet-like proliferation of uniform oval-shaped tumor cells in a fibrous background with prominent capillary-sized vessels. (b) The tumor was focally positive for FGF23 with a punctate perinuclear staining pattern, while blood vessels were negative. (c) Soft tissue invasion of the tumor cells. (d) Intracortical invasion of the tumor cells.
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On histological examination, the tumor was composed of sheet-like or vague storiform proliferation of uniform oval-shaped tumor cells in a fibrous background with prominent capillary-sized vessels (Figure 6(a)). Immunohistochemically, the tumor was focally positive for FGF23 (Figure 6(b)). Soft tissue invasion (Figure 6(c)) and intracortical invasion (Figure 6(d)) were identified in the extraosseous and intraosseous lesions, respectively.