Background: Extranodal NK/T-cell lymphomas (ENKTL) are rare non-Hodgkin's lymphomas with aggressive clinical behavior. ENKTL are frequently associated with the Epstein-Barr virus (EBV). Data on ENKTL in Africa and Arab world are extremely limited. The study investigated the clinicopathological characteristics, EBV infection, and immunophenotype of ENKTL in Tunisia. We conducted a retrospective study of ENKTL. Main clinicopathological features were reported. The expression of CD3, CD4, CD5, CD8, CD20, CD56, CD57, and Granzyme B were analyzed by immunohistochemistry. EBV infection was detected by IHC (LMP-1) and Epstein-Barr encoding region (EBER1/2) in situ hybridization. Results: A total of nine ENKTL were identified (mean age of 48 years and male-to-female ratio of 8:1). There were five nasal ENKTL, and the remaining four cases had extranasal involvement (palate, sub-mandibular gland, skin, and soft tissues of the ankle). The histopathology showed a lymphoid and pleomorphic proliferation characterized by images of angiocentrism. Strong and diffuse CD3 expression was observed in all cases. Tumor cells exhibited an expression of CD5 (two cases), CD8 (three cases), CD56 (six cases), CD57 (three cases), and Granzyme B (eight cases). All ENKTL cases were EBV-associated. Overall 5-year survival rate was 57%. Although six ENKTL were diagnosed at early clinical stages, the prognosis was unfavorable and associated with patient death in three cases. Conclusions: ENKTL are exceptional in Tunisia with unfavorable outcome. Histopathological diagnosis remains challenging in clinical practice. However, a careful histopathological examination combined with a correct interpretation of immunohistochemistry and in situ hybridization results refines the ENKTL diagnosis.

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Hemangiopericytoma is a rare tumor that arises from pericytes, classified as a low-grade malignant vascular tumor. It is characterised by a poorly clinical presentation and histologically, often confused with other fibrous tumors, which could pose difficulties on the diagnosis. The nasal cavity is an uncommon site. The rarity of this tumor imply the absence of management guidelines. So far, it still controversial regarding wether the endonasal surgery could control the tumor resection despite the wide performance, nowdays, of endoscopic techniques. It still unclear also conserning the use of embolization before surgery removal and the place of chemotheray. The high rate of recurrence impose long-term follow-up. So that, we report our experience through two cases and we aimed to discuss the clinical features and the differents treatement procedures. In fact, they are two women who consulted for epistaxis and nasal obstruction. Vascular masses were visualized with nasal endoscopy – one in the left nasal cavity and the second one had a destructive mass of the right hemiface . CT and MRI helped identify the mass, its margins and its extirpability. DiagnosIs was confirmed by histology. In one patient, surgery was performed. The second patient had an agressive and invading tumor for which chemotherapy was performed. The first patient remained free of disease after surgery. The second one had a fatal evolution.