The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of the Societies of Toxicologic Pathology from Japan (JSTP), Europe (ESTP), Great Britain (BSTP) and North America (STP) to develop an internationally-accepted nomenclature for proliferative and non-proliferative lesions in laboratory animals. The primary purpose of this publication is to provide a standardized nomenclature for characterizing lesions observed in the cardiovascular (CV) system of rats and mice commonly used in drug or chemical safety assessment. The standardized nomenclature presented in this document is also available electronically for society members on the internet (http://goreni.org). Accurate and precise morphologic descriptions of changes in the CV system are important for understanding the mechanisms and pathogenesis of those changes, differentiation of natural and induced injuries and their ultimate functional consequence. Challenges in nomenclature are associated with lesions or pathologic processes that may present as a temporal or pathogenic spectrum or when natural and induced injuries share indistinguishable features. Specific nomenclature recommendations are offered to provide a consistent approach.

Hematology and serum chemistry parameters were analyzed in 2 groups of pregnant rabbits to assess changes in these parameters over the course of gestation. These data were used to generate a historical control reference range for embryofetal development regulatory toxicology studies. During the 28-day gestation period, the following major changes were observed. Red blood cell counts, hemoglobin, and hematocrit increased slightly up to day 13

The 2010 annual National Toxicology Program (NTP) Satellite Symposium, entitled “Pathology Potpourri,” was held in Chicago, Illinois, in advance of the scientific symposium sponsored jointly by the Society of Toxicologic Pathology (STP) and the International Federation of Societies of Toxicologic Pathologists (IFSTP). The goal of the annual NTP Symposium is to present current diagnostic pathology or nomenclature issues to the toxicologic pathology community. This article presents summaries of the speakers' presentations, including diagnostic or nomenclature issues that were presented, along with select images that were used for voting or discussion. Some topics covered during the symposium included a comparison of rat and mouse hepatocholangiocarcinoma, a comparison of cholangiofibrosis and cholangiocarcinoma in rats, a mixed pancreatic neoplasm with acinar and islet cell components, an unusual preputial gland tumor, renal hyaline glomerulopathy in rats and mice, eosinophilic substance in the nasal septum of mice, INHAND nomenclature for proliferative and nonproliferative lesions of the CNS/PNS, retinal gliosis in a rat, fibroadnexal hamartoma in rats, intramural plaque in a mouse, a treatment-related chloracne-like lesion in mice, and an overview of mouse ovarian tumors.

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Lytic bony lesions which histologically consist of proliferation of well-differentiated small endothelial-lined blood or lymph vessels separated by loose connective tissue have been described in humans. These lesions have been termed skeletal angiomatosis, hemangiomas, and vascular malformations. 1.2.e8 This report describes a similar disease in three young cats.Case 1 was a 20-month-old male domestic long-haired cat which presented at 17 months of age for posterior paresis that was responsive to antibiotics and steroids. It re-presented at 20 months for bilateral proprioceptive deficits. Hemogram was normal, and feline leukemia virus tests were negative. Myelogram indicated obstruction of contrast material at T2 with decreased bony density at T,. Owners elected euthanasia. At necropsy the referring veterinarian found a pinkish-tan 1.0 x 0.5 x 0.3 cm extradural mass protruding into the spinal canal. The spinal cord in the region was compressed.Case 2 was a 1-year-old castrated male domestic shorthaired cat which presented at 14 months and again at 15 months of age for pain and progressive posterior paresis and ataxia. Plain radiographs showed a lytic area at TI,, I; a myelogram was compatible with extramedullary compression of the spinal cord at TI I . A surgical dorsal decompression at TI, and T I , was done. The bones of the dorsal laminae and articular facets appeared to the surgeons to be "thickened but porotic" and were felt to be the cause ofthe cord compression. Portions of these bones were submitted for histopathologic examination. Three months post-operatively the cat was free of clinical disease.Case 3 was a 15-month-old female domestic long-haired cat which had a 1 -year history of posterior paresis which was progressively less responsive to steroid therapy. Plain radiographs revealed a moth-eaten appearance of bone at T, involving the dorsal vertebral body, pedicles, and laminae. Myelogram indicated an extradural compression at T,. Owners elected euthanasia. The formalin-fixed and decalcified specimen of T, revealed red-brown irregular masses within the dorsal and transverse spinous processes on cut section. A 0.6 x 0.4 x 0.6 cm red-brown mass protruded into the spinal canal and compressed the adjacent spinal cord (Fig. 1).Histologically, sections from all cases were similar. Vessels of varying sizes with endothelial cells, prominent pencytes, and variable amounts of smooth muscle were present within a loose connective tissue stroma separated by bony trabeculae (Fig. 2). Some of these vessels, interpreted to be arterial, contained red blood cells; others were empty. The bony trabeculae were predominantly lamellar with moderate numbers of osteoblasts and infrequent osteoclasts present. Hemopoietic elements were displaced by vascular proliferations and stroma. Vascular proliferations extended along marrow spaces and vascular channels to the periosteum in case 1, and focally infiltrated a nerve in case 3, where extensive remodeling of surrounding bone was also found. These bony and vascular proliferat...