An unusual case of mediastinal mass with pleural and pericardial effusion

Myeloid sarcoma is a tumor mass consisting of myeloid blasts, with or without maturation, occurring in an anatomical site other than bone marrow. More 2000 case reports so far, only few comprehensive studies have been done, which reflects the rarity and difficulties treatment this neoplasm. : A 17-year-old female presented complaints neck swelling since 2 months, breathlessness 5 days. PET CT- Bilateral pleural pericardial effusion Large mediastinal mass, multiple enlarged lymph nodes appendicular skeleton showing increased FDG uptake. CT-Guided biopsy mass: Uniform blue cells sheets. CD45-Weak positive CD20, CD3, TdT-Negative CD99-Diffuse strong Parallelly, blood marrow examination was done. Peripheral smear-80% blasts. Bone marrow-Monomorphous population myeloblasts. About 21% Sarcomas (MS) are reported to occur mediastinum. Clinical presentation dependent on tumour location, symptoms due effect local organ dysfunction. Recent show misdiagnosis 25-47%, Hodgkin's lymphoma, lymphoblastic DLBCL, Ewing's sarcoma, thymoma, round cell tumours, poorly differentiated carcinomas, mostly inadequate immunophenotyping. It not corrected until diagnosis acute leukaemia later established by peripheral examination. Recognition MS with/without AML essential for prognosis. Correlating radiological, hematological, flowcytometry features histomorphology immunohistochemistry essential. rare possibility should be kept mind masses timely treatment.