Figure 1.

Photomicrographs of metastatic (A,B) and non-metastatic (C,D) pheochromocytoma cases with elevated PASS scores previously diagnosed at our institution. Scale bars are 25 micrometers for A,B and D, and 100 micrometers for C. (A) Nuclear pleomorphism in a pheochromocytoma with a total PASS score of 8. This tumor was resected from a 61-year old female who developed metastatic disease 9 years after initial diagnosis. (B) Same case displaying hypercellularity and nuclear hyperchromasia, two additional parameters included in the PASS algorithm. (C) Large and irregular nests in a pheochromocytoma with a PASS score of 7, diagnosed in a 41-year old male. The patient is alive without metastatic disease after 20 years of follow-up. (D) Same case displaying focal tumor cell spindling with elongated nuclei, a phenomenon yielding two PASS points.