Histological appearance of topical hemostatic agents and materials in neuropathology

Hemostatic agents and other foreign materials are frequently encountered in neuropathology samples. Recognizing these materials is crucial for accurate diagnosis and in the context of adverse events. This article provides an overview of macroscopic and microscopic characteristics of commonly used hemostatic agents and materials in neurosurgery. Samples of sterile hemostatic agents and retrospectively collected pathology slides were examined. Routine histopathological processing, special stains, and polarized light microscopy were utilized to document the appearance of these materials. A total of 22 hemostatic agents and 9 artifacts and foreign bodies were analyzed. Distinct macroscopic and microscopic properties, as well as effects of tissue processing, were documented. Recognizing hemostatic agents and materials is largely dependent on their main constituents. A constituent-based approach for identification of these materials is presented for the practicing neuropathologist.