Epithelioid hemangioendothelioma of the mandibular gingiva: report of a case and literature review

BACKGROUND: Malignant epithelioid hemangioendothelioma, or high-risk epithelioid hemangioendothelioma, is a low- to intermediate-grade vascular malignancy originally described by Weiss and Enzinger in 1982 as a vascular neo- plasm of endothelial origin. Epithelioid hemangioendothelio- mas have been reported in numerous locations, particularly the lungs, liver, soft tissues, viscera, skin, and bone. The World Health Organisation describes MEH as an intermedi- ate malignant neoplasm. MEHs are extremely rare in the oral cavity. Only eleven cases referred to MEH of the maxillary or mandibular gingiva. CASE REPORT: A 33-year-old male was referred to our Oral and Maxillofacial Service in 2009 for the evaluation of a forma- tion on the alveolar mucosa. A panoramic radiograph review showed a radiolucency between lateral incisor and second pre- molar roots. CT scans showed diffuse cortical bone loss. No signs of radiographic root resorption were detected. The patient denied any history of pain or swelling. A tissue punch biopsy was performed by removing two punches of tissue. A microscopic evaluation revealed fragments composed of a proliferation of spindled, ovoid, and epithelioid cells arranged in nests, cords, and short strands. The neoplastic cells were large and polygonal with an abundant and granular cytoplasm, nuclear pleomorphism, and nuclear hyperchromatism. The lesion exhibited small vascular channels with a moderate cel- lular inflammatory infiltrate, composed mainly of lympho- cytes, plasma cells, and eosinophils surrounding the vessels. Focal mitotic activity was identified, and the Ki-67 percentage score was 20%. After immunohistochemistry a diagnosis of MEH was made. No signs of metastasis were detected (cN0) by an investigation of the patient’s neck nodes, computed tomography, and ultrasonography. Anterior mandibular bone excision, including eight teeth and all related soft tissues, was performed under general anesthesia. A histologic examination of the lesion confirmed the diagnosis of MEH. The limits of resection were investigated to ensure clean and safe excision margins. No neck dissection was performed at this time. The patient was followed up at 15 days, 1 month, 3 months, 6 months, and then every 6 months for 4 years with a clinical investigation of soft tissues, clinical and ultrasonographic evaluations of lymph nodes, and radiographic assessment of bone healing. The entire follow-up period was 46 months. DISCUSSION: No consistent clinical or histologic criteria for predicting the biologic behavior of MEHs have been identified. A higher mortality rate is observed when epithelioid hemangioendotheliomas occur in bone, liver, or the lungs; therefore, the importance of immunohistochemical analyses to establish a definitive diagnosis should be emphasised. In this context, the majority of intraoral epithelioid hemangioendothelioma lesions were immunoreactive for CD34, CD31, fac- tor VIII-Rag, and vimentin, which characterise the epithelioid endothelial origin of this entity. It was not possible to identify common risk factors for MEH. The literature review indicated a mean age at diagnosis for MEH of 17±13.01 years, suggesting a predisposition to dis- ease in young people. Systemic metastases have been described in the literature at a rate of 21%, and a mortality rate of 17% has been described for cutaneous MEH, in accordance with the histological aspects of the malignancy. In gingival MEH no metastases has been described in literature before our report. Due to the potential malignancy of epithelioid hemangioen- dotheliomas, wide local excision is the treatment of choice for oral cavity cases according to the literature. The mean recurrence time was 21.33±23.44 months. Given the possibility of recurrence and metastasis several years after clean and safe excision, clinicians should apply at least 5 years of follow-up.