huge lump in the thymus region

[monsterlin]

My niece, who is at age 24, has been experiencing sore throat and itching on the whole body trunk at night during sleep starting from middle October 2016. A blood test done on Dec 7th 2016 found elevated leukocyte (20.39, normal range 3.5-9.5) and platelet counts and other abnormalities.  Contrast-enhanced CT scan shows irregular shape soft tissue mass in the thymus region, about 4.6x7.1 cm in size with obscure boundary. A CT-guided fine-needle aspiration biopsy and immunohistochemical test done on Dec 22nd could not confirm the mass in the mediastinum to be cancerous. While a repeated biopsy done on Jan 10th 2017 suspected the mass to be a tumor. No confirmed result is reached. She had no other symptoms or weight loss or decreased appetite. No fever or pain was observed, except the itching in the body trunk. Could anyone help to tell is it likely a thymoma or lymphoma? Is it look like benign? Any input is appreciated!