Erythroblastic sarcoma presenting as a unilateral pleural effusion in a patient with myelodysplastic syndrome/myeloproliferative neoplasm-Case report with cytologic and histologic findings.

Erythroblastic sarcoma (ES) is an extremely rare extramedullary solid tumor of immature erythroid cells, with around a dozen human cases to our knowledge presented so far in the english literature, none of the cases presenting as pleural effusion. Here we describe a case of ES in a thoracic wall diagnosed by cytological examination of pleural effusion with histologic correlation in a 53-year-old patient with a 10-month history of myelodysplastic syndrome/myeloproliferative neoplasm with grade III reticulin myelofibrosis.