Primary mediastinal large B-cell lymphoma, difficult differentiation from the epithelial neoplasm

Abstract

rimary Mediastinal Large B-Cell Lymphoma (PMBL) is a rare neoplasm that arises in the mediastinum, and then forms a mass. A female in 50s noticed malaise of right upper limb and a firm lump in the right clavicular region. After consulting with a nearby doctor, she was introduced to our medical center. Magnetic resonance imaging showed a giant mass (12 x 7 x 6 cm) in the anterior and superior mediastinum with expansion to the right supraclavicular fossa. Microscopic examinations of a biopsy specimen led to a diagnosis of PMBL. Methotrexate with Adriamycin, Cyclophosphamide, Vincristine, Prednisolone and Bleomycin (MACOP-B) chemotherapy was given as well as rituxan. Although CT scanning show a marked reduction in size, the tumor remained and radiation therapy was added. Two years later, the patient was transferred to our medical center, though died due to cardiac arrest. From the initial symptoms to death was approximately three years. Touch smear cytology results showed tumor cells present in loose aggregates, though some clusters had a tight aggregation, suggesting epithelial cells. The tumor cells showed abundant and clear cytoplasm, with round nuclei containing nucleoli, and numerous lymphoglandular bodies were also seen. Cells of tight in tight aggregates expressed CD20, in immunocytochemical results, and an epithelial neoplasm was ruled out.