Kaposiform hemangioendothelioma D18.0; C49.-

Niedt 1989 and Zukerberg 1993

Rare, solitary, vascular, non-metastatic, but locally aggressive growing (seminalignant) tumor of childhood, often associated with the Kasabach-Merritt syndrome.

60% of tumours are already present at birth or become manifest in the neonatal period (Fließer M et al. 2017). Occurrence also later (30%) in the first two years of life still possible.

Usually in the skin and subcutaneous fatty tissue; but also in the retroperitoneum, in the deep soft tissues of the thorax, arms, head or neck.

In the cutaneous form of kaposiform haemangioendothelioma (KHE), large red or blue nodules and plaques may appear. Often, however, there are deeper, soft tissue masses that can only be palpated or must first be detected by imaging examinations. Infiltrative growth is present. No distant metastasis. Regional lymph node involvement has been described. Cutaneous and subcutaneous variants of caposiform hemangioendothelioma suggest clinicopathologic overlap with tufted hemangioma .

In a larger study (n=215), an association between the median size of a KHE with and without Kasabach-Merrit syndrome was demonstrablyabt. Without KMP, the size of the KHE was 12 cm2 compared to 49 cm2 in association with a KMP (Schmid I et al. 2018).

Clinical:

• Infantile hemangioma: the differentiation may be difficult clinically. However, Kaposiform hemangioendothelioma is opposite in growth to infantile hemangioma, showing marked spontaneous regression after an intimal growth phase.
• Kaposi's sarcoma (does not occur in childhood).

Histologically:

• tufted hemangioma.

Kasabach-Merritt syndrome with thrombocytopenia and disseminated intravascular coagulation. The likelihood of consumption coagulopathy directly parallels tumor size and increases to 100% when multiple body regions are involved.

Clinical dermatological signs of coagulopathy: purpura and ecchymosis.

Superficial tumors can be excised. Deep tumor masses, e.g. in retroperitoneum or mediastinum, are often large and inoperable. Standard therapies do not exist (rarity of the tumor).

In a retrospective study that included 215 pat. the following therapy options were listed (Schmid I et al. 2018): In case of complete resection (not further classifiable whether R0 or R1) all patients were cured.

In inoperable patients, success with regression of tumor size was observed with the following therapies:

• 28 % - corticosteroids
• 39 % - vincristine
• 43 % - interferon alpha
• 61 % - antiplatelet agents
• 100 % - sirolimus.

Furthermore, therapeutic approaches with radiation or polychemotherapy were published.

Apparently, by far the best therapeutic successes were achieved with the TOP inhibitor sirolimus, which has an extremely good angiogenic and antiproliferative effect (Fließner M et al. 2017).

The tumor grows slowly but locally aggressive. In addition to cutaneous involvement, there may be involvement of internal organs (spleen, other parenchymal organs).

1. Blei F et al. (1998) Successfull multimodal therapy for kaposiform hemangioendothelioma complicated by Kasabach - Merritt - phenomenon: case report and review of literature. Pediatric Hematol Oncol 15: 295-305
2. Chu CY et al (2003) Transformation between Kaposiform hemangioendothelioma and Tufted angioma. Dermatology 206: 334-337
3. Cooper JG et al (2002) Kaposiform haemangioendothelioma: case report and review of the literature. Br J Plast Surg 55: 163-165
4. Fließer M (2017) Acute complications of vascular anomalies in childhood. Dermatologist 68: 792-795
5. Haisley-Royster C (2002) Kasabach-merritt phenomenon: a retrospective study of treatment with vincristine. J Pediatr Hematol Oncol 24: 459-462
6. Niedt GW et al (1989) Hemangioma with Kaposi-sarcoma-like features: report of two cases. Pediatr Pathol 9: 567-575

7. Schmid I et al. (2018) Kaposiform hemangioendothelioma in children: a benign vascular tumor with multiple treatment options. World J Pediatr 14:322-329.

8. Zukerberg LR et al (1993) Kaposiform hemangioendothelioma of infancy and childhood. An aggressive neoplasm associated with Kasabach-Merrit syndrome and lymphangiomatosis. Am J Surg Pathol 17: 312-328