A not so harmless mass: Kaposiform hemangioendothelioma complicated by a Kasabach–Merritt phenomenon

Indications and Limitations of Sirolimus in the Treatment of Vascular Anomalies—Insights From a Retrospective Case Series

“…The first reports on sirolimus in VA are derived from experience in critical clinical situations of vincristine-refractory VA with KMP, where the mTOR inhibitor seemed to yield a rapid response within the first week of treatment ( 1 – 3 , 25 ). Similarly, Tribolet et al added sirolimus to the treatment regimen of a patient with KHE and severe KMP not responding to an 8-day course of propranolol, steroid, and vincristine and observed rapid resolution of the lesion ( 26 ). A similar experience was reported by Cashell et al, where the initial regimen did not include propranolol ( 5 ).…”

"Kaposiform Hemangioendothelioma and Kasabach- Merritt Phenomenon: Effectiveness of Vincristine Combined to Steroids"

“…Schmid et al confirmed that infants and toddlers have a higher risk of developing a KMP as compared to older children [7]. It typically presents as an induration, plaque-like cutaneous lesion, bulky (> 5 cm), solitary, painful, ill-defined margins, and pebbly texture with violaceous color and involves multiple planes of tissue [4,6,8,9]. According to the World Health Organization histopathological classification (2013), Angiosarcomas (AS) and Epithelioid Hemangioendotheliomas (EHE) are malignant vascular tumors, whereas Kaposiform Hemangioendothelioma (KHE) is classified as a rarely metastasizing vascular neoplasm of intermediate malignancy [10].…”

“…The MRI findings in KHE are ill-defined margins, multiplanar involvement, diffuse enhancement, is intensity relative to muscle on T1-weighted imaging, hyperintensity on T2-weighted imaging and destruction/remodeling of adjacent bone [8]. Although Sauer et al demonstrated that total resection was not a favorable prognostic factor [10], the surgical excision is the gold standard if it can be done in healthy margins and with no deterioration but is rarely possible due to the infiltrative feature of the tumor [9,11]. The treatment involves tailored therapy depending on the lesion and surgical resection when feasible.…”

Sirolimus for Kaposiform Hemangioendothelioma and Kasabach-Merritt Phenomenon in a Neonate

“…Other institutions have reported similar variability and efficacy in neonate dosing with one using 0.8mg/m 2 per dose once daily, another starting at 0.1mg/kg per dose once daily, and another at 0.05mg/kg per dose twice daily. 23,[28][29][30] Similarly, trough levels have varied with reports of successful treatment at goal ranges of 2 to 3 ng/mL, 4 to 10 ng/mL, and 10 to 13 ng/mL. [29][30][31][32] As sirolimus becomes an increasingly acceptable oral treatment of KHE, standardization of dosing and acceptable therapeutic trough levels for neonates will require closer attention.…”

“…23,[28][29][30] Similarly, trough levels have varied with reports of successful treatment at goal ranges of 2 to 3 ng/mL, 4 to 10 ng/mL, and 10 to 13 ng/mL. [29][30][31][32] As sirolimus becomes an increasingly acceptable oral treatment of KHE, standardization of dosing and acceptable therapeutic trough levels for neonates will require closer attention. Our institution has the experience of successfully treating patients with sirolimus for vascular anomalies, including KHE, and we believe that sirolimus will become an increasingly acceptable and preferred option for treating vascular lesions in the future.…”