The patient had a surgical biopsy.
Histology
Macroscopy: The specimen consists of multiple tissue fragments, the largest measure 3 mm in greatest dimension.
Microscopy: Sections show multiple fragments of tissue with infiltrates of atypical spindled cells with hyperchromatic nuclei, small nucleoli and frequent mitoses. Intracytoplasmic PAS-positive accumulations are noted. Extensive coagulative necrosis but no osteoid production is seen. No evidence of lymphovascular invasion.
Immunohistochemistry negative for desmin, S100, AE1/AE3, SMA, BCL2, CD34 and EMA. CD99 is positive
Pathological diagnosis favours Ewing sarcoma.