Hairy Cell Leukemia Presenting as Presternal Soft Tissue Mass: A Case Report With Review of Literature

FIGURE 1. PET/CT scan 1 hour after the IV administration of 304 MBq of 18F-FDG showed an irregular, infiltrative mediastinal soft tissue mass centered on the anterior mediastinum with extensions to the presternal subcutaneous region and towards the diaphragmatic crura along the dorsal aspects of the pleura with FDG-avid bilateral anterior costophrenic mediastinal lymph nodes. Abstract: Hairy cell leukemia (HCL) is an uncommon chronic lymphoproliferative disorder. Initial presentation frequently includes symptoms related to peripheral blood cytopenias. It can sometimes have atypical manifestations and can present at unusual sites. We report an unusual presentation of HCL as a presternal soft tissue mass in a 45-year-old man. His peripheral blood counts showed pancytopenia. There were no palpable lymph nodes or hepatosplenomegaly. CT-scan revealed a middle mediastinal mass with extension into the presternal soft tissue. Tissue core biopsy was taken and histopathologic findings confirmed the diagnosis of HCL. To our knowledge, this is the second reported case of HCL presenting as a presternal soft tissue mass. Although rare, HCL should be considered in the differential diagnosis of tumors involving extramedullary/extranodal sites including the soft tissue and bone, so the patient can get the utmost benefit for early diagnosis of a treatment responsive disease.