ECP 2022 Abstract Book

Virchows Archiv (2022) 481 (Suppl 1):S1–S364 13 with keratinized stratified squamous epithelium, prompting the diagnosis of congenital hairy polyp. Conclusion: Congenital hairy polyps should be considered in the differential diagnosis in cases of life-threatening airway obstruc- tion in neonates. They are composed of tissues derived from meso- derm and ectoderm. Histological examination gives the definitive diagnosis, crucial in differentiating hairy polyp from other lesions, being essential for prognosis and follow-up. Malignant transforma- tion has never been reported. Surgical resection is the treatment of choice. Knowledge of this type of development malformation make easier early intervention and avoids significant morbidity. E-PS-11-004 Juvenile nasopharyngeal angiofibroma and familial adenoma- tous polyposis: an extraordinary case report J. Madeira*, B. Sepodes, M.R. Silva, M.J. Julião, M.A. Cipriano *Centro Hospitalar e Universitário, Portugal Background & objectives: Juvenile Nasopharyngeal Angiofibroma (JNA) is a rare and benign vascular neoplasm affecting almost exclusively adolescent males. It may occur as a component of the Familial Adenomatous Polyposis (FAP), making it 20-25 times more prevalent compared to the general population. Methods: We present a case of a 14-year-old male with a personal and familial history of FAP with colorectal polyps and cancer and desmoid tumours, presenting with a mass in his left nasal cav- ity, with recurrent epistaxis and nasal obstruction. MRI revealed a non-encapsulated lobulated heterogeneous mass lesion in the left side of the nasopharynx with 85x46x55mm, extending to adjacent structures. Results: He underwent tumour embolization followed by endoscopic excision. Gross examination revealed a fragmented lobulated and pedunculated mass. Histologically, it was a biphasic lesion with a vascular component consisting of variable sized and shaped vessels, small rounded or slit-like to larger staghorn, with variable wall thickness, with single layer of endothelium and occasionally smooth muscle wall. The stromal component varies from highly cellular, collagenized areas to less cellular regions with a fibromyxoid background. CD34 and CD31 immunohistochemistry highlighted endothelial cells. Smooth muscle actin showed the muscular wall of the vessels and beta-catenin revealed nuclear staining in tumour stromal cells and membranous/cytoplasmic staining in endothelial cells. Conclusion: FAP is an inherited autosomal dominant syndrome due to a defect in the APC gene characterized by multiple gastrointestinal adenomas and risk of adenocarcinomas and extracolonic manifestations. In patients with an association of PAF and JNA, mutations in APC gene were described in the stromal cells of the tumour, which highlights the idea that JNA may be the first manifestation of FAP. Therefore, it is important to consider FAP as an underlying condition in patients with a diagnosis of JNA. E-PS-11-005 A rare case of respiratory epithelial adenomatoid hamartoma of the nasal cavity H. Trihia*, S. Laskaris, E. Souka, G. Stanc, G. Galanopoulos, L. Karelis *Pathology Department Metaxa Cancer Hospital, Greece Background & objectives: Respiratory epithelial adenomatoid hamar- toma (REAH) is a rare benign proliferation of mature sinonasal tissue presenting as a polypoid mass, first described by Wenig and Heffner in 1995, mostly involving the posterior nasal septum. Surgical excision is the treatment of choice. Methods: A 38-year-old man with a history of unilateral nasal obstruction was diagnosed with a unilateral polypoid mass located in the left posterior nasal cavity in contact with the nasal septum. Simple surgical excision with functional endoscopic sinus surgery (FESS) was performed. Results: We received a yellowish polypoid mass with gelatinous, glistening outer surface, measuring 4,5X2X1cm. Microscopic examination showed a florid proliferation of widely spaced, partly confluent, small to medium, round to oval, partly cystically dilated tubular glands, lined by ciliated respiratory epithelium, without nuclear atypia. Invagination of the surface epithelium gave rise to ciliated tubular glands. Some glands showed mucinous metaplasia, similar to colonic glands. Some seromucinous normal glands were interspersed with the tubular glands. Stromal hyalinization was pre- sent with envelopment of glands by a thick, eosinophilic basement membrane. The stroma was oedematous, with inflammatory cells and eosinophils, similar to an inflammatory polyp. The diagnosis was of a respiratory epithelial adenomatoid hamartoma. Conclusion: REAH, is an uncommon entity with distinctive mor- phologic features including a glandular component originating from the overlying surface respiratory epithelium and polypoid growth as a result of respiratory epithelial adenomatoid prolifera- tion. REAH, especially those with a metaplastic mucinous compo- nent should be differentiated from low grade sinonasal adenocar- cinomas, which are locally aggressive tumours. REAH is CK20-/ CDX-2-, in contrast with the low-grade sinonasal adenocarcinoma. Pathologists must be aware of this entity in order to avoid overdi- agnosis and radical surgery. E-PS-11-006 Pleomorphic adenoma of the parapharyngeal space. A common tumour in an uncommon location H. Trihia*, S. Laskaris, M. Terzi, L. Karelis, I. Koutrafouris, G. Stanc *Pathology Department Metaxa Cancer Hospital, Greece Background & objectives: The majority of minor salivary gland tumours are malignant. Pleomorphic adenoma is the commonest benign tumour, most often found in the oral cavity. A very rare case of a large pleomorphic adenoma arising in the parapharyngeal space is reported. Methods: A 37-year-old man presented with difficulty in swal- lowing and obstructive sleep apnea of three months’ duration. CT scan showed a 7cm mass extending from the left lateral oropharynx to the larynx. There was no neck lymph node enlargement. The tumour was examined with transoral FNA, which was diagnostic of a pleomorphic adenoma. The tumour was transorally enucleated. Results: On gross examination the lesion was measuring 7X4X4,5cm, with a whitish, faintly lobulated and focally glistening cut surface. Histological examination showed a neoplasm with an admixture of epithelial and stromal components. Ducts lined by inner epithelial and outer myoepithelial cells surrounded by a chondromyxoid stroma, consistent with pleomorphic adenoma. Foci of quamous metaplasia were also present. Postoperative period was uneventful. Conclusion: Pleomorphic adenomas may occur in the para- pharyngeal space from displaced/aberrant salivary gland tissue within a lymph node, in contrast to tumours arising from minor salivary glands medial to the constrictor muscles of the pharynx or the deep lobe of the parotid gland. The treatment of choice is resection with adequate margins. For parapharyngeal tumours S280