Spontaneous lesions of the thyroid gland in goats (Capra hircus)

Abstract

The thyroid glands play an important role in the development of various tissues, thermoregulation, metabolic function and reproduction. Abattoir and necropsy-based studies provide an excellent opportunity for detecting diseases of both economic and public health importance. In the present study, thyroid glands from 150 goats were collected and the lesions were characterized. Correlations of gross and histopathological findings, gross and histomorphometry were carried out. The macroscopic findings recorded in the thyroid gland of abattoir and necropsy cases were thyroid gland with normal appearance (87.33%); paler than normal (3.33%); darker than normal (8.33%); brownish black discolouration (0.66%); gland with solitary nodule in the parenchyma (0.33%) and cyst(s) in the hilar region (6.33%). Out of 150 thyroid glands studied, it was observed that the histology of both lobes was not uniform. The microscopic findings recorded were: thyroid gland with normal histoarchitecture (3.66%), ultimobranchial cyst (28.33%), vacuolar degeneration (25.66%), follicular degeneration (13%), cystic degeneration (6%), mineralization of cyst (0.33%), congestion (27.66%, inter-follicular haemorrhages (2.66%) and intra-follicular haemorrhages (4.66%), focal atrophy (7.66%), hypertrophy of follicular epithelium (14.66%), follicular epithelial hyperplasia (24.33%), C-cell hyperplasia (25.33%), colloid goitre (4%), melanin pigmentation (4%), macrofollicles (19.33%), microfollicles (5.33%), focal fibrosis (17.33%), signet ring variant of follicular cell adenoma (2%), C-cell adenoma (0.66%) and capillary hemangioma (0.33%). Morphological examination including histopathology of endocrine glands is a sensitive parameter for the detection of compounds that adversely affect gland function. This information would be useful in interpreting and grading the severity of changes related to any specified treatment effect.