ALK-positive anaplastic large T-cell lymphoma presenting primarily as a sinonasal mass with pseudoproptosis: A case report

Abstract

We report a case of anaplastic lymphoma kinase-positive anaplastic large T-cell lymphoma (ALK+ALCL) presenting primarily as a sinonasal mass with pseudoproptosis in an 11-year-old boy. The diagnosis was based on histopathological and immunohistochemical (IHC) evaluation, which is indispensable for determining tumor type. On the basis of clinicoradiological findings, provisional differential diagnoses of angiofibroma and rhabdomyosarcoma were made. Upon histopathological examination of the biopsy sent, the diagnosis of lymphoma in the sinonasal region was considered. Upon IHC, the tumor cells showed immunoreactivity for vimentin, CD45, CD30, and ALK. The tumor cells showed focal immunoreactivity for CD3 and CD68. Ki-67 labeling index was 70%. They were nonimmunoreactive for PAN cytokeratin, epithelial membrane antigen, cluster of differentiation (CD) 20, CD15, CD56, S100, smooth muscle actin, and myogenin. The diagnosis of ALK+ALCL was rendered. The studied IHC markers confirmed the histopathological diagnosis and helped in further subtyping. To the best of our knowledge, this is the first case of ALCL presenting primarily as a sinonasal mass with pseudoproptosis.