AGGRESSIVE EPITHELIOID HEMANGIOENDOTHELIOMA OF THE THYROID : CASE REPORT

1. Department of Pathological Anatomy, Hospital Mohammed VI, Marrakech, Morocco. 2. Department of Otorhinolaryngology, Hospital Mohammed VI, Marrakech, Morocco. 3. Department of Radiology, Hospital Mohammed VI, Marrakech, Morocco. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History Received: 23 November 2019 Final Accepted: 25 December 2019 Published: January 2020 .

Epithelioid hemangioendothelioma (EHE) of the thyroid is an extremely rare disease; only five cases have been reported in the English literature to our knowledge. We report a case of a 57 year-old male presented with hematoma and recurrent thyroid mass after total thyroidectomy. Surgical exploration revealed the presence of a hematoma with tumor recurrence at the thyroid lodges. The histopathological and immunohistochemical findings indicated an EHE of the thyroid. With the rarity of Epithelioid hemangioendotheliom of the thyroid there is no standard therapy and the prognostic factors are unclear. Curative resection may be an effective treatment, further cases and studies are needed.

Introduction:-
Epithelioid haemangioendothelioma (EHE) was first described by Dail and Leibow in 1975 in lung and called « intravascular bronchioloalveolar Tumor ». After, in 1982 Enzinger and Weiss described it as a low-grade but potentially aggressive vascular neoplasm in soft tissu (1,2). It occurs mainly in bone, soft tissue, lung and liver (3). We report a case of primary malignant EHE of the thyroid very aggressive having recurred after surgical treatment with an unfavorable prognosis.

Case presentation
A 57-year-old non alpine mal was referred to our center for a recurrent post thyroidectomy hematoma. The patient had undergone a total thyroidectomy two months earlier that was complicated with a hematoma after nine days. Then he underwent two interventions for the drainage of the hematoma without success.
At admission the patient was pale and had anterior cervical mass ( Figure 1). Nasofibroscopy showed a paralysis of the left vocal cord. The blood work revealed profound hypothyroidism with a moderate anemia. A full body Computed Tomography scan showed a 12 cm cervico-thoracic hematoma occupying the thyroid lodge ( Figure 2 Table 1. The diagnosis of hemangioendothelium epithelioid was retained.     It has been described in bone, soft tissues and other organs such as lung, liver, spleen, brain, breast, heart, skin, peritoneum, and mediastinum (6, 3) but we found just five cases reported to date in the English literature in thyroid(1, 2,5, 7) (  ratio is 1/4(9). In all cases, age is between 35 and 74 years with no predominance of any range. Unfortunately we do not have the patient's medical record before thyroidectomy, so we do not know the number, the size or the location of the nodules, but in the previous cases, tumor size was between 2.1cm and 8 cm, and all patients had a single nodule of the thyroid, contrary to other organs associated with multiple organ involvement in 36% of cases (8). The previous cases and our present case are summarized in Table 2.
Histologically, the tumor is consisting of chain and cords of epithelioid endothelial cells distributed in a myxohyaline stroma. The tumor cells centrifugally extend from the lumen of a large vessel to the surrounding tissue. This lumen contains tumor cells, necrotic debris and dense collagen (3). The cells have eosinophilic cytoplasm containing vacuoles called blister-cells and that deforms them and contains fragmented erythrocytes. Most of the time, the cells are low grade. This tumor express vascular markers especially CD34, CD31 and also FLI 1 and ERG transcription factor. In some cases we find a positivity of epithelial antigens CK7, CK8 and EMA (4).
At the molecular level the presence of CAMTA1 gene in 1p36 with WWTR1 gene fusion in 3q23-24 EHE was demonstrated (5,4). This abnormality has been reported in the majority of EHEs at various anatomical sites, but he is not found in other epithelioid vascular tumors (5). It was confirmed in one case of thyroid EHE (1). In our case the search for molecular anomaly has not been realized.
The prognostic actors of EHE are the presence of pulmonary lesions, multiorgan involvement, age, and sex (5). In addition, mitotic activity (>3 mitotic figures/50 high-power fields) and size (>3.0 cm) have been used such as high risk factors in soft tissues (4). Although the thyroid EHE patient with the largest tumor (80 mm) died 13 months after the diagnosis , the other patients, whose tumor sizes were all <4 cm, had uneventful outcomes (5).In soft tissue 20-30% of tumors metastasize and about 15% of patients die (4). Our patient died within a few days of the anatomopathological diagnosis.