Case 10 -

Non-keratinizing Carcinoma of the Sinonasal Tract Dr. Llúcia Alós Hospital Clinic, University of Barcelona Spain

Clinical History A 61 years-old man presented with rhinorrhea and progressive nasal obstruction for 5 months. The CT scan showed a tumour located at right nasal fossa and ethmoid sinus, with bone destruction. A biopsy of the tumour was performed. Case 10 - Slide 1 Click to view with ImageScope Click to view with a Web-Based Viewer Diagnosis: Non-keratinizing Carcinoma of the Sinonasal Tract Discussion Non-keratinizing carcinoma (NKC)of the sinonasal tract has been referred to by a variety of terms, including schneiderian carcinoma, cylindrical cell carcinoma and transitional cell carcinoma. In the new WHO classification of Head and Neck tumours [1] it is considered a variant of squamous cell carcinoma. It represents about 10% of all malignant tumours of the sinonasal tract, and about 30% of the squamous cell carcinomas in this region [2, 3]. It is a tumour with distinctive clinicopathological features. It affects predominantly males in the 7th decade of life. It originates frequently from nasal fossa and ethmoid sinus, followed by maxillary sinus. Symptoms include nasal obstruction, rhinorrhea and epistaxis. In advanced cases, the patients may present proptosis, diplopia or lacrimation. Grossly, it may be exophytic, fungating or papillary; friable or indurated. Histologically it is characterized by an exophytic papillary and plexiform or ribbon-like growth pattern. Usually it infiltrates as smooth masses in the underlying stroma, frequently with central necrosis. The neoplastic cells are medium to large size, sometimes with cylindrical or basaloid morphology and marked nuclear atypia. It can resemble histologically transitional carcinoma of urothelial origin. Real squamous differentiated cells are frequently seen, but usually there is not marked keratinization. Also, scattered mucous cells can be seen. In our experience, most of these NKC of the sinonasal tract express immunohistochemically p16 protein and high-risk Human Papillomavirus DNA is detected by PCR, according to published recent studies [4]. These tumours tend to express low p53 positivity and high proliferative index labelled with Ki-67 [4]. A differential diagnosis must be made with benign and malignant epithelial tumours originating in the sinonasal tract: inverted sinonasal papilloma, keratinizing squamous cell carcinoma (KSCC), basaloid-squamous cell carcinoma and sinonasal undifferentiated carcinomas (SNUC). Sinonasal papillomas, also termed schnederian papillomas are very common lesions that orininate in the sinonasal tract. In the inverted type papilloma the epithelium invaginates into the underlying stroma. It is composed of multilayered epithelium which can be squamous or ciliated columnar type, sometimes admixed with mucous cells. Five to ten percent of cases may show varying grades of dysplasia. However, when marked and diffuse atypia is seen, a malignant transformation should be considered. The incidence of malignant change of inverted papillomas ranges from 2-27%. The malignant tumour is usually a keratinizating squamous cell carcinoma [1, 2, 3, 5]. KSCC is histologically identical to that originated in other locations of upper respiratory tract. It shows variable degrees of keratinization and can be well, moderately or poorly differentiated. The growth and infiltration patterns of this tumour are usually different than NKC. However, when NKC shows real squamous differentiation, it is difficult to separate both entities. Basaloid-squamous cell carcinoma mainly originates in hypopharynx and supraglottic larynx. The presentation in sinonasal tract is uncommon. It is an aggressive variant of squamous cell carcinoma that is characterized by rounded nests of cytologically highly atypical basaloid epithelial cells. Often they have a pseudoglandular or strand-like arrangement with production of basement membrane-like material. SNUC is an infrequent tumor composed of pleomorphic epithelial cells which form nests, lobules, trabeculae and sheets, in the absence of squamous or glandular differentiation [6]. The cells are usually small or medium-sized, have scant cytoplasm and very atypical nuclei. Mitotic figures are common, as well as necrosis, vascular and perineural invasion. The treatment of choice of NKC is surgical resection of the tumor. Radiotherapy is recommended, as this tumor is sensitive to it [7]. At diagnosis, NKC usually invades adjacent structures, and it is difficult to perform surgery with wide free margins. For this reason tumoral recurrences are frequent. Metastases to regional lymph nodes may occur, but the patient death usually takes place when the tumor invades endocranial structures. References Nasal cavity and paranasal sinuses. Chapter 1. In Head and Neck Tumours. Pathology and Genetics. World Health Organization Classification of Tumours, Lyon 2005. Tumors of the Upper Aerodigestive Tract and Ear. S E Mills, MJ Gaffey, HF Frierson. Atlas of Tumor Pathology. AFIP, Washington 2000. Pathology of the Head and Neck. A. Cardesa and P.Slootweg Eds. Chapter 2: Nasal cavity and paranasal sinuses.A Cardesa, L Alos, A Franchi. In:. Springer. Heildeberg, New York 2006 (in press). El Mofty SK, Lu DW. Prevalence of high-risk human papillomavirus DNA in nonkeratinizing (cylindrical cell) carcinoma of the sinonasal tract. A distict clinicopathological and molecular disease entity. Am J Surg Pathol 2005; 29:1367-1372. Barnes L. Schneiderian papillomas and nonsalivary glandular neoplasms of the head and neck. Mod Pathol 2002; 15: 279-297. Frierson HF, Mills SE, Fechner RE et al. Sinonasal undifferentiated carcinoma: an aggressive neoplasm derived from schneiderian epithelium and distinct from olfactory neuroblastoma. Am J Surg Pathol 1986; 10:771-779. Osborn DA. Nature and behaviour of transitional tumors of the upper respiratory tract. Cancer 1970; 25:50-60.