Fine-needle aspiration cytology of metastatic nasopharyngeal carcinoma in cervical lymph nodes: comparison with metastatic squamous-cell carcinoma, and Hodgkin's and non-Hodgkin's lymphoma.

Abstract

Our objective was to study the cytomorphological features of metastatic nasopharyngeal carcinoma (NPC) as compared to squamous-cell carcinoma (SCC) of nonnasopharyngeal origin, Hodgkin's lymphoma (HL), and non-Hodgkin's (NHL) lymphoma in the neck lymph nodes. The aim of this study was to find simple cytological criteria using routine stains that can help in differentiating between these entities. All fine-needle aspiration (FNA) smears of metastatic NPC, SCC, HL, and NHL from neck nodes available in our files were included in this study. Nodal disease was the first clinical manifestation in all cases of NPC, and all the lesions were of the nonkeratinizing type. The cytomorphological features of metastatic NPC, SCC, HL, and NHL have been described. Metastatic NPC and HL had a similar reactive lymphoid background, with eosinophils, plasma cells, and sometimes epithelioid-cell granulomas. The bizarre cells of NPC showed some resemblance to Reed-Sternberg cells of HL. However, the latter can be distinguished from the former on the basis of bulky, pale gray, vacuolated cytoplasm and vesicular nuclei with sharply demarcated prominent macronucleoli. In NPC, the neoplastic cells form distinct aggregates contrasting with the normal lymphoid cells in the background, which was different from the monotonous dispersed population of cells in NHL. Moreover, bizarre cells, prominent nucleoli, and the presence of plasma cells, eosinophils, and granulomas were not common features of NHL. The smears of metastatic SCC revealed keratinized malignant cells in all cases, while eosinophils and plasma cells were absent in the background. Plasma cells were seen intimately related to tumor cells in all cases of NPC. In conclusion, metastatic NPC can be differentiated from metastatic SCC of nonnasopharyngeal origin, HL, and NHL on the basis of simple nuclear and cytoplasmic features of malignant cells and their background. The presence of plasma cells intermingling with tumor-cell clusters is a good indicator of nasopharyngeal origin. On the other hand, a nasopharyngeal origin is unlikely in the presence of keratinized malignant cells.