Clinical and pathological features of Kasabach-Merritt phenomenon associated with kaposiform hemangioendothelioma and tufted angioma.

Abstract

Objective To investigate the clinical and pathological features of Kasabach-Merritt phenomenon （KMP） associated with Kaposiform hemangioendothelioma （KHE） and tufted angioma （TA）. Methods Clinical presentations and pathological features of seven patients with KHE or TA complicated by KMP were analyzed retrospectively and a literature review was made. Results Five patients were diagnosed with KHE and two with TA, and all of them exhibited a decrease in platelet count （less than 100×10^9/L）. In all patients, lesions were present or developed on the trunk or limbs at birth or within one month after birth. The lesions showed a rapid growth in two patients, slow expansion in two patients, kept stable or regressed gradually in three patients. Lesion appearance varied in KHE and TA, and characteristic manifestation was dark-erythematous or pmnosus tumors or patches involving the skin or subcutis. Histopathologically, both KHE and TA were composed of numerous fusiform endothelial cell clumps arranged in a lobular fashion. The nodules of KHE had an indistinct boundary usually with erythrocyte stasis or hemosiderin deposition, and TA was characterized by rounded, well-defined nodules distributed in a crater-like fashion within the dermis. A satisfactory outcome was achieved in two patients treated with oral dehydrocortisone and one patient with surgical resection plus skin grafting; the other four patients remained untreated and no progress was observed during follow-up. Conclusions KMP is pathologically associated with KHE or TA. KHE is an intermediate tumor with local aggressiveness while TA is a benign tumor. Both of them can regress spontaneously and should be differentiated from other types of vascular tumors. Key words: Kasabach-Merritt phenomenon; Hemangioendothelioma; Hemangioma