Neuroectodermal tumours of the sino-nasal tract: a clinicopathological study of 18 cases with a newly proposed revised classification and a brief review of literature.

aimSino-nasal tract tumours constitute 3% of the head and neck malignancies. Among these tumours, neuroectodermal tumours are rare with histo-morphological and immunohistochemical overlap making them a challenge for the pathologist. We included Ewing's/PNET, olfactory neuroblastoma (OFN), mucosal malignant melanomas (MMM), Melanotic neuroectodermal tumour of infancy (MNTI), small-cell neuroendocrine carcinoma (SNEC), and the newest entity Adamantinoma like Ewing's sarcoma (ALES) as part of the neuroectodermally derived tumours of the sino-nasal tract. The last three entities were added to the existing ones, which also has been emphasized in this paper. METHODS AND

resultsA comprehensive analysis was done on all neuroectodermally derived tumours from 2016 to 2020. A total of 18 cases were collected, which included OFN (10 cases), SNEC (2 cases), MMM (2 cases), Ewing's/PNET (2 cases), MNTI (1 case), and ALES (1 case). The most common presentation in NE tumours was nasal obstruction (80-100%). Except for OFN, all other tumours were confined to the nasal and paranasal sinuses. 4/10 cases of OFN showed orbital extension. Cervical lymph-node metastasis was seen in 50% of cases of SNEC and MMM groups. An array of relevant immune-histochemical markers were performed. The marker expression was very subtle among the groups. On follow-up, recurrence was seen in the OFN and MMM groups in 30 and 50%, respectively. Metastasis was seen in SNEC group (100%) and OFN group (10%).

conclusionAs sino-nasal neuroectodermal tumours pose a diagnostic challenge and have different therapies and are prognostically different, the pathologist must be aware of the subtle morphological, immunohistochemical clues which have been dealt with in-depth in this study.