PMC9826552_01
Pre-operative radiographs. Pre-operative posteroanterior (a) and lateral (b) radiographs demonstrated a lytic and expansile lesion originating proximally at the subchondral base of the distal phalanx with loss of radial cortex and a transverse fracture.
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F1
Pre-operative MRI. Pre-operative MRI sequences: Sagittal T2 fat suppressed image (a) demonstrates a homogeneous expansile mass lesion measuring 9.5 x 11.5 x 9.6 mm within the proximal portion of the distal phalanx. T1 coronal fat suppressed image (b) shows expansion through the radial cortex.
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F2
T2 fat sequences showed foci of hyperintensity within the lesion that may represent internal calcification, and these features were felt to be in keeping with an enchondroma (Fig. 2).
Intra-operative picture. Intra-operative picture (a) demonstrating minimally invasive radial approach with cortical defect and (b) macroscopic picture of excised specimen.
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F3
The capsule was removed (Fig. 3) and the distal phalanx was curetted and washed out. 2 cc of a synthetic injectable composite calcium sulfate and phosphate graft was utilized as a void filler.
Intra-operative fluoroscopy. Intra-operative fluoroscopy (a) PA and (b) lateral post-curettage showing complete removal of lesion and subsequent intra-operative fluoroscopy (c) PA and (d) lateral post-bone graft injection and k-wire insertion.
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F4
A 1.2 mm k-wire was inserted retrograde crossing the distal interphalangeal joint (Fig. 4) due to the significant bone defect.
Post-operative radiographs. Posteroanterior (a) and lateral (b) radiographs 3-month post-surgery after wire removal demonstrating fracture healing and creeping substitution of bone graft.
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F5
The wound healed well (Fig. 5) and at 6-week postoperatively, the DASH score was 0.
Histology of the lesion. Low magnification view (a) of the cyst wall (x20) showing a thin layer of squamous cell epithelium and abundant keratinization. High magnification view (b) of the keratinized squamous cell epithelium (x100) with retained granular layer.
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F6
Histology of the excised material revealed an epidermal cyst measuring 12 x 10 x 8 mm (Fig. 6).