%0 Journal Article
%T Synchronous Papillary Carcinoma and Hemangiopericytoma with Lung Metastases
%A Nicola Malagutti
%A Valeria Iannini
%A Andrea Rocchi
%A Francesco Stomeo
%A Antonio Frassoldati
%A Michela Borin
%A Stefano Pelucchi
%J Case Reports in Otolaryngology
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/231758
%X Hemangiopericytomas (HPC) are uncommon tumors that originate from perivascular cells of capillary vessels. HPC are about 1% of all vascular tumors and can be found in the head-neck region with an incidence between 16% and 33%. HPC is a neoplasm of uncertain malignant potential; it can behave as an aggressive tumor with metastases and increased mitotic activity or as a relatively benign neoplasm with only local development. In this paper we describe a case of hemangiopericytoma with uncertain malignant potential with cervical location associated with a concomitant papillary thyroid carcinoma and lung metastasis of unknown origin; this case led us to follow a specific and uncommon diagnostic and therapeutic strategy. 1. Introduction Hemangiopericytomas (HPC) are uncommon tumors that originate from perivascular cells known as pericytes of Zimmerman, localized around capillary vessels. For the first time these neoplasms were called hemangiopericytomas in 1942 by Stout and Murray who described them as tumors composed of proliferation of capillary vessels and rounded cellular elements [1]. Pericytes have characteristics of smooth muscle cells and probably have role in blood flow regulation. After studies with electronic microscope, it has been supposed that these cells could be derived from primitive mesenchymal precursors and could represent a form of transition between mesenchymal and smooth muscle cells [2]. Hemangiopericytomas are about 1% of all vascular tumors and can be found in the head-neck region with an incidence between 16% and 33%; HPC have been described inside orbit, nose, oral cavity, parotid gland, parapharyngeal space, jugular foramen, and so forth [3, 4]. This neoplasm can appear at any age but it is predominant between 6th and 7th decade and equally distributed between sexes. Etiology is unknown, but traumas, long therapies with corticosteroids, or hormonal imbalances may be involved [4]. HPC is a neoplasm of uncertain malignant potential; it can behave as an aggressive tumor with metastases and increased mitotic activity or as a relatively benign neoplasm with only local development [5]. Immunohistochemical profile is often heterogeneous with characteristics close to solitary fibrous tumors. HPC are classified as benign, borderline, and malignant, depending on some histopathological features (mitotic activity, cellularity, and nuclear atypia) and clinical behavior (presence of necrosis and tumor size) [6, 7]. However, the histopathological distinction between benign and malignant HPC can be difficult. In fact, the biological behavior of
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