{Reference Type}: Case Reports {Title}: B-cell Lymphoblastic Lymphoma of the Paranasal Sinuses: A Case Study of a Rare Clinical Entity. {Author}: Anderson BP;Metz CM; {Journal}: Cureus {Volume}: 14 {Issue}: 11 {Year}: Nov 2022 暂无{DOI}: 10.7759/cureus.31565 {Abstract}: Lymphoblastic lymphoma is a rare and aggressive form of non-Hodgkin lymphoma (NHL). The tumor can derive from T-cell or B-cell and is clinically similar to acute lymphoblastic leukemia with minimal to no bone marrow involvement distinguishing the two. We present a rare case of lymphoblastic lymphoma originating from the paranasal sinuses. A 40-year-old male presented to the emergency department and was diagnosed with right-sided acute sinusitis complicated by pre-septal cellulitis. After failing medical management, he underwent endoscopic sinus surgery. Pathologic analysis of nasal contents stained for CD79a, CD34, and PAX5, suggesting a B-cell lymphoblastic lymphoma (B-LBL). He was referred to hematology-oncology and was treated with hyperfractionated cyclophosphamide, vincristine, Adriamycin, dexamethasone (Hyper-CVAD). Short-term follow-up has thus far demonstrated near-complete resolution of the tumor. Non-Hodgkin lymphomas of the paranasal sinuses are rare, and B-cell lymphoblastic lymphomas comprise just 0.3% of adults with NHL. Immunohistochemical phenotyping for B-LBL is typically positive for B-cell markers CD19, CD20, CD22 and CD79a. Classic treatment involves a chemotherapy regimen of Hyper-CVAD with an overall survival rate of 66%. B-cell lymphoblastic lymphoma is rarely reported in the paranasal sinuses. A thorough history and physical exam along with a complete workup, including biopsies with histopathological and immunohistochemical analysis, needs to be obtained. Little is known about its prognosis when the primary site is within the paranasal sinuses, and therefore, patients need prompt and aggressive treatment when the diagnosis is made.