Polymorphic reticulosis is a necrotizing atypical lymphoproliferative lesion with distinctive clinical and pathologic features. It is a preferred term for Lethal midline granuloma because it is more precise and describes the morphology of disease. Clinically it is characterized by a predilection of upper respiratory track at which disease process is extremely destructive and the lesion spreads to the soft tissues of face, adjacent tissues of the orbit, cartilage and bone. Other lesions also can be involved. Diagnosis can be made by biopsy and multiple biopsies may be necessary because necrosis and nonspecific inflammatory changes may be present in various diseases. Best results of treatment are obtained in localized lesions of the upper respiratory track early with high dose radiation therapy. Authors experienced 2 cases of polymorphic reticulosis with submandibular mass who died after radiation therapy and prednisolone and reported with brief review of literatures.