I have to admit this is a difficult diagnosis on frozen. The observation by byg is very insightful and accurate "切片像恶性，可涂片看起来又不像恶性".

• This case demonstrates the utility of touch prep imprint cytology - excellent cytologic details (round regular nuclei, small nucleoli, abundant eosinophilic cytoplasm etc.), features suggesting a more benign neoplasm.
• Frozen diagnosis: testicular neoplasm, favor leydig cell tumor (with consultation with colleagues)
• Final diagnosis: Leydig cell tumor (LCT) with focal marked cytologic atypia, with comment to have close follow-up. Selective immunostains support the diagnosis.
• Comment: LCT with marked cytologic atypia may have low malignant potential.  However, no reliable cytologic features can predict malignancy. Features that may suggest a malignant LCT include marked cytologic atypia, frequent or atypical mitoses, lymphovascular invasion and local invasive behavior.  The only reliable criteria for a malignant LCT diagnosis will be presence of distant metastasis.    

???

Too easy? too hard? need more pictures or information?

What's your frozen section diagnosis or differential diagnoses?