Nasopharyngeal Capillary Arteriovenous Malformation with Ancient/Symplastic Change: A Simulator of Malignancy GORDANA SAMARDZIJA, 1 SLAVISA M. DJURICIC, 1,2* IVAN BALJOSEVIC, 3 AND EDUARDO CALONJE 4 1 Department of Clinical Pathology, Mother and Child Health Care Institute of Serbia Dr Vukan Cupic, Belgrade, Serbia 2 Banjaluka University School of Medicine, Banjaluka, Bosnia and Herzegovina 3 Department of Otorhinolaryngology, Mother and Child Health Care Institute of Serbia Dr Vukan Cupic, Belgrade, Serbia 4 Department of Dermatopathology, St John’s Institute of Dermatology, St Thomas’ Hospital, London, United Kingdom Received September 16, 2015; accepted October 21, 2015; published online November 3, 2015. ABSTRACT There are only 8 published cases of symplastic hemangioma (SH), a relatively recently described, distinct benign entity characterized by pleomorphic vascular smooth muscle and interstitial cells in a pre-existing, long-standing vascular lesion. Seven of these cases were of SH in cutaneous locations, and 1 case was described in the mediastinum. We report the case of the 12-year-old girl with a nasopharyngeal tumor mass with prominent symplastic changes arising in the background of a combined capillary arteriovenous malformation. After critical analysis of all published cases of SH, it is clear that these lesions commonly represent capillary arteriovenous malformations (CAVM) with ancient/symplastic changes according to current terminology proposed in the classification required by the International Society for the Study of Vascular Anomalies (ISSVA). This is the first such lesion reported in a mucosal location and presenting in the pediatric age group. CAVM with ancient/symplastic change follows a benign clinical course, but it can simulate a malignant vascular tumor. Key words: diagnosis, nasopharynx, pathogenesis, sym- plastic hemangioma, vascular malformation INTRODUCTION During the last decade, along with the understanding of the origin of a wide spectrum of vascular lesions and changes in their nomenclature, several new entities have been described [1]. Symplastic hemangioma (SH) is defined as a distinct and rare benign entity characterized by pleomorphic vascular smooth muscle and interstitial cells in a pre-existing, often long-standing vascular lesion [1,2]. Including the 3 cases first described by Tsang and colleagues [3] in 1994, only 8 SH cases have been published until now [2–4]. Seven SHs were cutaneous, and 1 case was located in the mediastinum. The reported patients were middle-aged to elderly [1,2]. We report the case of a 12-year-old girl with a capillary arteriovenous malformation (CAVM) in nasopharyngeal mucosa with histological features that completely fit SH. After a critical analysis of all published cases of SH, it is clear that those need to be correctly categorized as CAVM with ancient or symplastic change according to accepted terminology of the biology-based clinical pathologic classification required by the International Society for the Study of Vascular Anomalies (ISSVA) [5,6]. CASE REPORT Clinical findings A 12-year-old girl was admitted to hospital with a 1-year history of symptoms of nasal obstruction and nasal discharge suspected to be secondary to a polyp in the right nasal cavity. The patient had been previously treated with oral antihistamines and nasal steroids for 1 month without improvement of symptoms. During this period, she developed obstructive sleep disturbances and difficulty swallowing. Oropharyngoscopy and fiber endoscopy revealed a whitish, polypoid nodule protruding from the nasopharynx and completely obstructing the right and partially obstructing the left nasal cavity. A computed tomography scan showed a tumor in the nasopharynx and shading of the right maxillary sinus (Fig. 1). A pale pink nodule measuring 7 3 3 cm, attached with a broad base to the posterior nasopharyngeal wall, was surgically removed in 3 pieces with minimal bleeding. The patient received no postoperative therapy, and oropharyngoscopy showed no evidence of tumor recurrence on regular check ups for 3 years after the operation. Pathology findings Grossly, the tumor consisted of 3 irregular pieces with a total mass of 8.56 g. The largest piece had a maximum *Corresponding author, e-mail: slavisa.djuricic@gmail.com Pediatric and Developmental Pathology 19, 249–253, 2016 DOI: 10.2350/14-09-1547-CR.1 ª 2016 Society for Pediatric Pathology