DNA-PLOIDY OF PHEOCHROMOCYTOMA ON CYTOLOGY SPECIMEN BY IMAGE-ANALYSIS

Pheochromocytoma usually shows prominent nuclear atypia, but the prese nce of such atypical cells is known to be an unreliable predictor of m alignancy. DNA ploidy of pheochromocytomas has been analyzed by flow c ytometry or photospectrometry on paraffin-embedded tissue, but the res ults were controversial. We performed DNA analysis on cytology specime ns of 11 pheochromocytomas using an image analysis system. All tumors had a mixed pattern of a large population of diploid cells and a small population of polyploid cells. DNA content correlated with nuclear si ze, and larger cells had more DNA content. Such larger tumor cells had polyploid nuclei, such as 4 C, 8 C, 16 C, and 32 C, in both malignant and benign pheochromocytomas. The larger polyploid nuclei may result from difficulty of duplication at the mitotic phase of the cell cycle.