An unusual case of mediastinal mass with pleural and pericardial effusion

Abstract

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