Clinical and imaging features of Kaposiform Hemangioendothelioma

Abstract

Objective: Kaposiform hemangioendothelioma (KHE) is a unique locally aggressive vascular tumor with poor prognosis. The aim of this study is to assess the clinical and imaging features of KHE, and to compare the differences between solitary and diffusive infiltrative subtype further.

Methods: The clinical and radiological findings of a cohort of 25 cases with histologically proven KHE, between June 2011 and June 2016, were reviewed retrospectively. 7 solitary and 18 diffusive infiltrative subtypes KHE were included. The differences of clinical and imaging features between these two subtypes were compared statistically by Wilcoxon rank sum test and Fisher exact test.

Results: The median age was 4 months old. 20 cases (80%) were accompanied by Kasabach-Merritt phenomenon (KMP). Most KHE located in trunk and/or extremity. The masses showed inhomogeneous echogenicity and were rich in vascularity on ultrasound; showed isoattenuation relative to muscle on unenhanced CT, isointense (n = 15) or slightly hyperintense (n = 7) T₁ weighted imaging (T₁WI) signal relative to muscle, mainly heterogeneous hyperintense or slightly hyperintense with speckled hypointense (n = 17) T₂WI signal (77%) relative to muscle, and notable (n = 15) and moderate (n = 3) enhancement. Feeding and draining vessels were revealed in 15 cases. Five masses with DWI showed slightly restricted diffusivity, with average apparent diffusion coefficient value of (1.28 ± 0.09) × 10^-3 mm² s^-1. Necrosis and hemorrhage were also found. Compared with solitary ones, diffusive infiltrative KHE were larger, more commonly accompanied by KMP and reticular lymphedema, and more frequently located in trunk and/or extremity.

Conclusion: Five masses with DWI showed slightly restricted diffusivity. A hypervascular mass accompanied by KMP and reticular lymphedema, with speckled hypointense signal T₂WI signal, especially in pediatric patients, is highly suggestive of the diagnosis of KHE. Advances in knowledge: Speckled hypointense signal T₂WI signal, and notable enhancement were unique features of KHE. KHE showed slightly restricted diffusivity on DWI, commonly accompanied by KMP and reticular lymphedema.

Figure 1.

A 21-months-old male having KHE(m) in the left ischium. (a–c) Coronal T₁WI, axial and coronal FS T₂WI show isointense signal relative to muscle on T₁WI, and heterogeneous hyperintense signal relative to muscle on T₂WI with surround edema(e). FS, fat-suppressed; KHE, kaposiform hemangioendothelioma; T₁WI, T₁ weighted imaging; T₂WI, T₂ weighted imaging.

Figure 2.

A 1-month-old male having well-defined solitary mass (white arrow) in the left cervical region. (a) Coronal T₁WI showed mainly isointense signal relative to muscle, with focal hyperintense signal hemorrhage. (b) Axial T₂WI showed heterogeneous hyperintense signal relative to muscle. (c, d) Coronal- and axial-enhanced T₁WI showed heterogeneous notable enhancement with peripheral feeding and draining vessels (v). T₁WI, T₁ weighted imaging; T₂WI, T₂ weighted imaging.

Figure 3.

A 3-month-old male having diffusive infiltrative KHE(m) located in intra-abdominal and retroperitoneal space with infiltrative growth pattern (invasion of pancreas, porta of liver and spleen(s), vessels of retroperitoneum), and ascites. (a) Axial T₁WI showed mainly slightly hyperintense signal relative to muscle. (b, c) Axial T₂WI and FS T₂WI showed heterogeneous slightly hyperintense signal with speckled hypointense signal relative to muscle (white arrow), obscure boundary of mesentery and adipose tissue. (d) Axial-enhanced T₁WI showed heterogeneous moderate enhancement. FS, fat-suppressed; KHE, kaposiform hemangioendothelioma; T₁WI, T₁ weighted imaging; T₂WI, T₂ weighted imaging.

Figure 4.

A 2-month-old male having diffusive infiltrative KHE located in left thoracic wall (white arrow). (a) Coronal FS T₂WI showed mainly heterogeneous hyperintense, with speckled hypointense signal relative to muscle. (b) Axial-enhanced T₁WI showed heterogeneous moderate enhancement. (c) DWI (800 s mm^–2) show heterogeneous hyperintense signal relative to muscle. FS, fat-suppressed; KHE, kaposiform hemangioendothelioma; T₁WI, T₁ weighted imaging; T₂WI, T₂ weighted imaging.

Figure 5.

Light microscopy findings and immunohistochemical staining of KHE. (a) A slice of HE staining show infiltrating nodules composed of spindle endothelial cells. (b) CD34 is positive in spindle endothelial cell. KHE, kaposiform hemangioendothelioma.