Benign nodular hyperplasia - Figure 6. Cytological features - oxyphilic metaplasia.

Oxyphilic metaplasia is not an infrequent phenomenon in the case of hyperplastic nodules. The presence of colloid and the lack of prominent nucleoli are the most important keys to avoid overinterpretation of oxyphilic cells (1st row). Unfortunately, the clear distinction between a non-tumorous metaplasia and an oxyphilic tumor is not possible in each case (2nd row).