Syncytial variant of nodular sclerosing Hodgkin's disease: fine-needle aspiration findings in two cases. 
The syncytial variant is a recently described, uncommon form of nodular sclerosing Hodgkin's disease that was previously termed "sarcomatoid."  In addition to foci of typical sclerosis, it is characterized histologically by sheets or clusters of mononuclear Reed-Sternberg variants.  These may be arranged around areas of necrosis with variable numbers of neutrophils.  In excised material, differential diagnostic considerations include non-Hodgkin's malignant lymphoma, granulocytic sarcoma, malignant melanoma, metastatic carcinoma, thymoma, and metastatic germ cell tumor.  We describe the fine-needle aspiration cytologic finding in two examples of this entity.  Cohesive clusters and sheets of malignant cells with clear cytoplasm, vesicular nuclei, and prominent nucleoli are easily mistaken for metastatic carcinoma or germ cell tumor.  Ancillary tests useful in this differential diagnosis are discussed.