Polymorphic reticulosis is rare disease and a necrotizing atypical lymphoproliferative lesion with distinctive clinical and pathologic features. Considerable debate and confusion have existed in the literature about the entity of polymorphic reticulosis, but it is a preferred term because it is more precise and describes the morphology of disease. Clinically it is characterized by progressive unrelenting ulceration and necrosis of the upper respiratory tract and the midline facial tissue or possibility of later dissemination, but polymorphic reticulosis involving deep neck space and soft tissue of the neck is extremely rare. We experienced a case of polymorphic reticulosis involving deep neck who died during radiation therapy, so report this case with a brief review of the literatures.