Ultrastructural Findings in Adrenal Cortical Adenomas Clinically Mimicking Pheochromocytoma: A Comparison with Other Adrenal Tumors and Tissue Preparation Techniques
Carmen M Perrino, David N Prall, Edward P Calomeni, Tibor Nadasdy, Debra L Zynger. Ohio State University Medical Center, Columbus, OH
Background: Adrenal cortical tumors with catecholamine elevations clinically mimicking pheochromocytomas are extremely rare. The impact of tissue preparation methods on electron microscopy (EM) images in adrenal tumors is unknown. Tissue preparation methods were assessed in adrenal cortical adenoma (ACA) clinically mimicking pheochromocytoma, pheochromocytoma, and ACA lacking pheochromocytoma-like symptoms.
Design: 10 adrenal cortical tumors were examined using EM after employing a variety of tissue preparation techniques including fixation with glutaraldehyde, formalin for varying lengths of time followed by glutaraldehyde, and/or formalin followed by paraffin-embedding. Electron micrographs were assessed for image quality, the presence of dense secretory granules, and the presence of eccentric, norepinephrine (NE)-type granules.
Results: Images created from tissue fixed in glutaraldehyde and/or formalin and subsequently resin-embedded were of good quality while images from paraffin-embedded specimens were poor with disrupted cellular architecture. Pheochromocytoma fixed in glutaraldehyde for 24 hours or in formalin for 8 days demonstrated eccentric granules. These granules were absent in tissue fixed in formalin for 20 days or obtained from a paraffin block. Both ACA without pheochromocytoma-like symptoms and ACA clinically mimicking pheochromocytoma had non-eccentric dense core granules and lacked eccentric NE-type granules on EM regardless of tissue preparation.
Conclusions: ACA is a rare cause of pheochromocytoma-like symptoms. These tumors lack eccentric, NE-type dense core granules that are present in pheochromocytoma. Fixation in glutaraldehyde alone or formalin followed by glutaraldehyde produces electron micrographs which may aid in the diagnosis of adrenal cortical tumors, however formalin-fixed paraffin-embedded tissue results in images that are inadequate for pathological examination.
Monday, March 4, 2013 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 316, Monday Morning