Cytomorphology of adrenocortical carcinoma and comparison with renal cell carcinoma

OBJECTIVE: To review the cytomorphologic features of adrenocortical carcinoma (ACC), correlate them with histology and compare them with the cytomorphologic features of very similar renal cell carcinoma (RCC) on fine needle aspiration (FNA) smears. STUDY DESIGN: Cytomorphologic features in 7 cases of ACC in FNA smears were analyzed and compared with those in 10 cases of RCC. Five cases of ACC and five of RCC were later confirmed on histopathology. Parameters analyzed pertained mainly to architectural, cytoplasmic and nuclear features. RESULTS: The presence of cells in sheets with a central, thin-walled vascular core (endocrine vascular pattern); monomorphic cell population; eccentric nuclei; focal dramatic anisonucleosis; and focal spindling with crushing was a prominent feature of ACC in contrast to RCC, which showed mainly an acinar pattern with only a focal endocrine pattern, well-defined cytoplasmic angles and projections, and cytoplasmic vacuolations; pleomorphism, if present, was gradual and seen uniformly in all the cells. Univariate analysis using the (2)(chi) test showed the presence of endocrine architecture; focal dramatic anisonucleosis; crushed spindle fragments; eccentric nuclei; and absence of cytoplasmic vacuolizations as significant differentiating features in favor of ACC (P < .05). CONCLUSION: A cytomorphologic comparison of ACC with RCC showed that differentiation is possible by a set of statistically significant features that not only have diagnostic value but, as with crushed spindle fragments, also have prognostic significance.