The primary clear cell
tumor of the lung is an extremely rare benign
tumor. This
tumor is called "
sugar tumor" since clear cell
tumor of the lung contains abundant
glycogen. We here present a case of lung clear cell
tumor of the lung associated to
essential thrombocythemia. To the best of our knowledge, there is no report about this association. A 44-Year-Old Woman admitted to our clinic with a 2-month history of
fatigue. On physical examination, the spleen was 3 cm palpable below the left costal margin on the mid axillary line. The laboratory tests revealed an elevated platelet counts (1,014,000/mm(3)). A pulmonary nodule (3,5 cm) was detected in the upper right lobe on the chest X-ray. Then, thoracic computed tomography (CT) was planned. The nodule looked like benign pattern on CT scan and total excision was performed for curative and diagnostic treatment. Microscopically, the
tumor was composed of nests of rounded or oval cells with distinct cell borders, optically clear cytoplasm and small nucleus. By immunohistochemistry,
tumor cells were positive for HMB-45, NSE and focal S100
antigen. And, it was diagnosed as clear "
sugar" cell
tumor. After
tumor excision the lasting
thrombocytosis induced us to perform bone marrow biopsy and JAK2 mutation research. Diagnosis of
Essential Thrombocythemia was made. In conclusion, it is important to make an evaluation for myeloproliferative diseases in clear "
sugar" cell
tumor in adults if
thrombocytosis was lasting
after treatment.