case_images: PMC11769867_01
case_images: Lateral radiograph of the right humerus (A) demonstrates an aggressive permeative lesion of the right humerus (black arrowheads) with a pathological fracture (black arrow). AP radiograph of the elbow (B) shows aggressive lesions of the distal humerus and proximal ulna (black arrows) and large soft tissue mass medial to the elbow (white arrowheads)
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case_images: PMC11769867_01_256_2024_4727_Fig1_HTML.jpg
case_images: Fig1
case_images: There was a subacute pathologic fracture of the proximal and mid right humeral diaphysis with an underlying ill-defined permeative lesion with wide zone of transition and cortical thinning (Fig. 1). There were areas of cortical destruction at the elbow along the medial humeral epicondyle and proximal ulna with an associated overlying mass-like soft tissue swelling (Fig. 1).
case_images: CT axial image at the level of the humeral head (A) shows area of cortical destruction (black arrowhead) with enhancing soft tissue (black arrows). At the level of the elbow (B), there are skin thickening (white arrowhead), tortuous blood vessels (white arrow), and erosion of the medial humeral condyle (black arrowhead)
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case_images: PMC11769867_01_256_2024_4727_Fig2_HTML.jpg
case_images: Fig2
case_images: There was an enhancing soft tissue mass that extended into the proximal humeral diaphyseal intramedullary space with associated endosteal scalloping and cortical thinning (Fig. 2).
case_images: Gray scale (A) and Doppler (B) ultrasound images of the antecubital fossa demonstrate a large, heterogeneous, vascular mass (arrows in A)
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case_images: Fig3
case_images: A right upper extremity ultrasound examination was ordered for evaluation of deep vein thrombosis and demonstrated a heterogeneously hypoechoic, hypervascular mass replacing the muscle architecture with multiple anechoic, cystic areas with internal septations and dilated traversing vessels (Fig. 3).
case_images: Axial post-contrast-enhanced T1W fat-saturated image of the upper arm (A) shows a heterogeneously enhancing mass extending to the skin (block arrows). Coronal contrast-enhanced T1W fat-saturated image of the upper arm (B) shows heterogeneous enhancement of the muscles with dilated, tortuous vessels coursing through the mass without compression (white arrowheads in B and C). Note preserved normal marrow signal distal to the lesion (white arrow). Sagittal post-contrast-enhanced T1W fat-saturated image of the upper arm (C) demonstrates an enhancing soft tissue (asterisk) with underlying cortical destruction (white arrowheads) and surrounding long head of the biceps tendon (black arrow)
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case_images: Fig4
case_images: Throughout the upper arm, there was extensive heterogeneous soft tissue enhancement with STIR hyperintensity with loss of the normal muscular architecture, extending to the skin surface and containing multiple dilated traversing vessels without stenosis (Fig. 4).
case_images: A Low power view reveals the lesion to be composed of innumerable "finger-like" projections composed of endothelial-lined vascular spaces enveloped by bland fibrous connective tissue and tiny fragments of striated muscle and adipose tissue at the edge [H & E, 40 x]. B At higher power, tiny organized thrombi are appreciated in the center of the field. The papillary projections again demonstrate endothelial cells admixed with collagen cores and rare inflammatory cells filling the luminal space [H & E, 200 x]. C Low power view with CD31 and D CD34 stains highlighting the endothelial cells in the mass [10 x]
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case_images: PMC11769867_01_256_2024_4727_Fig5_HTML.jpg
case_images: Fig5
case_images: No cellular atypia was noted (Fig. 5).