Retiform Hemangioendothelioma of the Neck

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. Vascular tumors are categorized into benign hemangiomas, frankly malignant angiosarcomas, and tumors of intermediate malignancy. Hemangioendotheliomas are of intermediate ma-lignancy and encompass a broad range of histologic entities, including retiform, epithelioid, kaposiform, polymorphous, and composite sub-types. 1 Retiform hemangioendothelioma (RH) is an extremely rare disease entity of unknown etiology that was first described by Calonje et al. 2 in 1994 as a vascular neoplasm of intermediate malignancy. It is characterized by a high rate of local recurrence and a low frequency of metastasis, and its bio-logic potential is between that of hemangiomas and angiosarco-mas. RH reportedly presents primarily as an exophytic dermal tumor of the extremities. 3 We present the first report of RH arising in the neck without dermal involvement. A previously healthy 27-year-old woman presented to the outpatient department of our institution in February 2012 with a painless mass on the left side of the neck, which had increased in size over the course of one year. She had no constitutional symptoms such as weight loss, fever, or decreased appetite , and the rest of her medical history was also unremarkable. Physical examination revealed a 4×3-cm mass occupying the left side of the neck at the level III lymph node region. On pal-pation, the lesion was non-tender, hard, movable, and showed well-defined and smooth borders. The overlying skin was normal. Cervical lymph node enlargement was not observed, and the remainder of the otolaryngopharyngeal examination was unremarkable. Ultrasound-guided fine-needle aspiration was performed, and the cytology results were negative for malig-nancy. Computed tomography of the neck showed a well-defined heterogeneous mass with prominent ring enhancement occupying the left side of the neck at the level III lymph node region (Fig. 1). Surgical excision revealed a well-encapsulated and hypervascular tumor within the left anterior neck triangle. Histologic examination revealed a 3.8×2×2-cm solid tumor with clear surgical margins. The tumor was composed of vascu-lar structures containing elongated and narrow arborizing vas-cular channels simulating the structure of a rete testis (Fig. 2). The vascular channels were lined with hobnail endothelial cells (Fig. 3), which demonstrated rare mitosis. The tumor cells were immune-reactive for CD31 and friend leukemia virus integration 1 (Fli-1), but not for smooth muscle …