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Tertiary hypothyroidism in a dog.

Shiel RE, Acke E, Puggioni A, Cassidy JP, Mooney CT - Ir Vet J (2007)

Bottom Line: Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved.A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination.Tertiary hypothyroidism has not been previously reported in dogs.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland. robert.shiel@ucd.ie.

ABSTRACT
: A nine-year-old male entire Labrador was diagnosed with pituitary dependent hyperadrenocorticism. Following seven months of successful mitotane therapy, the dog presented with marked weight gain, seborrhoea and alopecia. Routine clinicopathological analyses revealed marked hypercholesterolaemia. Serum total and free thyroxine (T4) concentrations were below their respective reference ranges. Serum thyroid stimulating hormone (cTSH) concentration was within reference range. TSH and thyrotropin releasing hormone (TRH) response tests revealed adequate stimulation of total T4 in both, and cTSH in the latter test. Magnetic resonance imaging revealed a mass arising from the pituitary fossa, with suprasellar extension. A diagnosis of tertiary hypothyroidism was made. Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved. Euthanasia was performed four months later due to the development of neurological signs. A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination. Tertiary hypothyroidism has not been previously reported in dogs.

No MeSH data available.


Related in: MedlinePlus

Midline sagittal section of formalin-fixed brain revealing a 2 cm diameter, well-demarcated mass (indicated with arrow) that is largely replacing the hypothalamus.
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Figure 3: Midline sagittal section of formalin-fixed brain revealing a 2 cm diameter, well-demarcated mass (indicated with arrow) that is largely replacing the hypothalamus.

Mentions: Post mortem examination revealed the presence of a highly infiltrative pituitary adenoma with effacement of the overlying hypothalamus (Figure 3). Pituitary histopathology revealed a dense aggregate of pleomorphic cells of cuboidal to polygonal outline with eosinophilic cytoplasm and ovoid, frequently hyperchromatic nuclei. Tumour cells were noted pallisading around blood vessels. Rare attempts at acinar formation were observed. Multinucleated cells and karyomegaly were features and one mitotic figure per high power field was counted (Figure 4). A small amount of compressed pituitary tissue was identified grossly but was not apparent on histopathology sections. The thyroid gland was grossly reduced in size. Histopathologically, there was a large percentage of small diameter follicles containing clumped or little colloid with no evidence of inflammatory cell infiltration. The corticomedullary junction of both adrenal glands was irregular with a cortical-medullary ratio of 1:1. Histopathology revealed cortical atrophy with hyperplastic nodules and foci of mineralisation within the cortex.


Tertiary hypothyroidism in a dog.

Shiel RE, Acke E, Puggioni A, Cassidy JP, Mooney CT - Ir Vet J (2007)

Midline sagittal section of formalin-fixed brain revealing a 2 cm diameter, well-demarcated mass (indicated with arrow) that is largely replacing the hypothalamus.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3113834&req=5

Figure 3: Midline sagittal section of formalin-fixed brain revealing a 2 cm diameter, well-demarcated mass (indicated with arrow) that is largely replacing the hypothalamus.
Mentions: Post mortem examination revealed the presence of a highly infiltrative pituitary adenoma with effacement of the overlying hypothalamus (Figure 3). Pituitary histopathology revealed a dense aggregate of pleomorphic cells of cuboidal to polygonal outline with eosinophilic cytoplasm and ovoid, frequently hyperchromatic nuclei. Tumour cells were noted pallisading around blood vessels. Rare attempts at acinar formation were observed. Multinucleated cells and karyomegaly were features and one mitotic figure per high power field was counted (Figure 4). A small amount of compressed pituitary tissue was identified grossly but was not apparent on histopathology sections. The thyroid gland was grossly reduced in size. Histopathologically, there was a large percentage of small diameter follicles containing clumped or little colloid with no evidence of inflammatory cell infiltration. The corticomedullary junction of both adrenal glands was irregular with a cortical-medullary ratio of 1:1. Histopathology revealed cortical atrophy with hyperplastic nodules and foci of mineralisation within the cortex.

Bottom Line: Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved.A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination.Tertiary hypothyroidism has not been previously reported in dogs.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Agriculture, Food Science and Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland. robert.shiel@ucd.ie.

ABSTRACT
: A nine-year-old male entire Labrador was diagnosed with pituitary dependent hyperadrenocorticism. Following seven months of successful mitotane therapy, the dog presented with marked weight gain, seborrhoea and alopecia. Routine clinicopathological analyses revealed marked hypercholesterolaemia. Serum total and free thyroxine (T4) concentrations were below their respective reference ranges. Serum thyroid stimulating hormone (cTSH) concentration was within reference range. TSH and thyrotropin releasing hormone (TRH) response tests revealed adequate stimulation of total T4 in both, and cTSH in the latter test. Magnetic resonance imaging revealed a mass arising from the pituitary fossa, with suprasellar extension. A diagnosis of tertiary hypothyroidism was made. Following four weeks of levothyroxine therapy, circulating cholesterol concentration had declined, weight loss had ensued and dermatological abnormalities had improved. Euthanasia was performed four months later due to the development of neurological signs. A highly infiltrative pituitary adenoma, with effacement of the overlying hypothalamus was identified on post mortem examination. Tertiary hypothyroidism has not been previously reported in dogs.

No MeSH data available.


Related in: MedlinePlus