Proceedings of the 2016 National Toxicology Program Satellite Symposium

Abstract

The 2016 annual National Toxicology Program (NTP) Satellite Symposium, entitled “Pathology Potpourri” was held in San Diego, California, at the Society of Toxicologic Pathology’s (STP) 35th annual meeting. The goal of this symposium was to present and discuss challenging diagnostic pathology and/or nomenclature issues. This article presents summaries of the speakers’ talks, along with select images that were used by the audience for voting and discussion. Some lesions and topics covered during the symposium included malignant glioma and histiocytic sarcoma in the rodent brain; a new statistical method designed for histopathology data evaluation; uterine stromal/glandular polyp in a rat; malignant plasma cell tumor in a mouse brain; Schwann cell proliferative lesions in rat hearts; axillary schwannoma in a cat; necrosis and granulomatous inflammation in a rat brain; adenoma/carcinoma in a rat adrenal gland; hepatocyte maturation defect and liver/spleen hematopoietic defects in an embryonic mouse; distinguishing malignant glioma, malignant mixed glioma and malignant oligodendroglioma in the rat; comparison of mammary gland whole mounts and histopathology from mice; and discussion of the International Harmonization of Nomenclature and Diagnostic Criteria (INHAND) collaborations.

Proceedings of the 2019 National Toxicology Program Satellite Symposium

“…18 SOX-10 is a neural crest transcription factor that is required for Schwann cell and melanocytic differentiation and survival. 25 Epithelial membrane antigen is a protein thought to be involved in cell secretion that is positive in perineurioma and meningioma. 23 Table 4 summarizes additional immunohistochemical markers for schwannoma and its differential diagnoses.…”

Evaluation of Cystic Endometrial Hyperplasia and the Normal Estrous Cycle in Longitudinal Sections of Uterus from Female Harlan Sprague-Dawley Rats

“…2,3,17 This prompted a new directive to review both longitudinal and transverse histological sections of the female reproductive tract, including uterus body, uterine horns, cervix, and vagina, in their subsequent rodent studies. 1,2,3,17 The protocol for removal of the uterus currently being used by the NTP obtains both longitudinal and transverse histological sections (Supplemental Figure S1). Despite the new directive, very little to no reference material is available for the phases of the normal estrous cycle, much less spontaneous and inducible lesions, in longitudinal sections of rat or mouse uteri.…”

“…The National Toxicology Program (NTP) has recently introduced the practice of examining longitudinal histological sections of the female rodent reproductive tract, including the body of the uterus, uterine horns, cervix, and vagina in the NTP 2-year bioassay. 1 Although longitudinal histological sections have been used for NTP reproductive assessment by continuous breeding (RACB) and modified one generation (MOG) studies, this practice was first implemented in the NTP 2-year bioassay during the oral gavage study of tetrabromobisphenol A (TBBPA) to improve the identification of non-neoplastic lesions, preneoplastic lesions, and uterine tumors, particularly uterine tumors that may not have been identified grossly. 2,3 Although the recent NTP Historical Control database on the Hsd:Sprague Dawley SD ® (Hsd:SD) rat is based on longitudinal sectioning of the uterus, 1,4 the industry standard is to process and review transverse sections of each uterine horn.…”

“…1 Although longitudinal histological sections have been used for NTP reproductive assessment by continuous breeding (RACB) and modified one generation (MOG) studies, this practice was first implemented in the NTP 2-year bioassay during the oral gavage study of tetrabromobisphenol A (TBBPA) to improve the identification of non-neoplastic lesions, preneoplastic lesions, and uterine tumors, particularly uterine tumors that may not have been identified grossly. 2,3 Although the recent NTP Historical Control database on the Hsd:Sprague Dawley SD ® (Hsd:SD) rat is based on longitudinal sectioning of the uterus, 1,4 the industry standard is to process and review transverse sections of each uterine horn. 5,6 In fact, most of the references available for the normal histology, spontaneous lesions, and inducible lesions in the female rat and mouse reproductive tract predominantly include transverse sections of uterus.…”

Proceedings of the 2017 National Toxicology Program Satellite Symposium

“…The National Toxicology Program (NTP) Satellite Symposium is a 1-day meeting that has traditionally been held in conjunction with the annual Society of Toxicologic Pathology (STP) meeting (Adams et al 2011; Bach et al 2010; Boorman et al 2012; Elmore et al 2014; Elmore et al 2015; Elmore et al 2016; Elmore et al 2017). The objective of this annual symposium is to provide continuing education on interpreting histopathology slides.…”