The smears clearly show a population of malignant cells.

The cytomorphologic features (large atypical cells, macronucleoli, syncytial architecture, relative paucity of lymphoglandular bodies) suggest a non-lymphoid malignancy.   

Hence, a metastatic poorly differentiated / undifferentiated carcinoma is high on the list, this being an Asian patient. 

It would be prudent to check the clinical notes to see if the post-nasal space has been examined, and, if so, whether there is an accompanying biopsy. If there is, a morphologic comparison could be made of both samples, as the node likely represents metastatic nasopharyngeal carcinoma.

Any necessary stains can be performed on the biopsy (eg. EBER-ISH).

Each report (cytology and histology) should contain a reference to the other. 

• If there is no accompanying PNS biopsy, then one could see if there is available material from the FNA for a cell block, and perform EBER-ISH on it. 
• If no cell block is available, it should be signed out as metastatic poorly differentiated carcinoma with appropriate comments to direct further investigation  (see sample diagnosis below).

Moderately cellular smears show large, highly atypical cells occurring both singly and in syncytial sheets. The cells contain large, round to ovoid nuclei featuring prominent nucleoli, The nuclei are 3-5 times the diameter of resting lymphocytes. Many of the cells contain delicate ill-defined cytoplasm, and some dispersed cells occur as bare nuclei. 

A mixed lymphoid population is noted in the background. 

Diagnosis: Cervical lymph node, FNA: Metastatic poorly differentiated carcinoma.

Comments: In this region (South-East Asia),  nasopharyngeal carcinoma should be excluded. Recommend correlation with relevant clinical investigations, eg. nasoendoscopy.

The cytology demonstration videos can be viewed below.