Kaposiform hemangioendothelioma of the thigh: A case report

Abstract

Kaposiform hemangioendothelioma is a rare, locally aggressive or borderline vascular tumor that typically affects infants. It presents as a purpuric cutaneous lesion and may be associated with life-threatening coagulation disorders, such as the Kasabach-Merritt phenomenon. The differential diagnosis can be challenging based on clinical presentation alone. Imaging plays a crucial role in the diagnostic workup, particularly magnetic resonance imaging. We present a case report of a 4-month-old patient with an enlarging vinous cutaneous mass on the thigh and coagulation abnormalities. Magnetic resonance imaging revealed a large, infiltrative, soft-tissue lesion with poorly defined margins and heterogeneous enhancement, that involved all muscle compartments of the thigh and was associated with lymphedema, stranding of the subcutaneous fat and cutaneous thickening. These findings were consistent with kaposiform hemangioendothelioma of the thigh and the diagnosis was confirmed by histopathological characterization.

Keywords: Kaposiform hemangioendothelioma; Kasabach-Merritt Syndrome; Magnetic resonance imaging.

Fig. 1

Photograph of the thigh lesion. There is a large mass with vinous cutaneous colouration on the right thigh, accompanied by leg and thigh edema and leg petechie.

Fig. 2

Magnetic resonance imaging of the right thigh. Axial T2-weighted image (A), axial T1-weighted image (B), axial postcontrast T1-weighted image with fat suppression (C), and axial postcontrast T1-weighted image with fat suppression subtraction image (D) show an infiltrative soft tissue lesion with poorly defined margins that involves all muscle compartments of the thigh, centred on the medial one. The central portion is isointense on the T2 and T1 weighted images (star, A and B), while the more infiltrative peripheral portion shows significant hyperintensity on the T2 and T1 weighted images (arrowheads, A and B). After contrast administration, the lesion demonstrates diffuse heterogeneous enhancement (arrows, C and D). There is also diffuse soft tissue edema with enhancing reticular stranding in the subcutaneous fat, mostly perpendicular to the skin surface, associated with enhancing cutaneous thickening (dashed arrow, C and D).

Fig. 3

Magnetic resonance imaging of the right thigh. Coronal (A) and sagittal (B) postcontrast T1-weighted images with fat suppression demonstrate the infiltrative and locally invasive nature of the lesion. The large soft tissue mass involves all muscle compartments of the thigh and shows heterogeneous enhancement after contrast administration (arrowheads, A and B).

Fig. 4

Histology of the lesion. Hematoxilin-eosin slides of the biopsy specimens (A–C) revealed an infiltrative dermal centred vascular lesion arranged in confluent nodules (A) composed of spindled endothelial cells and numerous vascular splitlike spaces (B) that lack mitotic activity and atypia (C). Immunohistochestry (D–G) shows reactivity for CD31 (D) and podoplanin (D) in the endothelial of the vascular spaces. There was no expression of GLUT-1 (E) or HHV-8 in the above-mentioned cells.