Morphometry, topography and arterial supply of the thyroid gland in brazilian shorthair cat

Thyroid gland diseases are the most common endocrinopathies in feline practice. Diagnosis and surgical treatment must base on solid anatomical knowledge about the gland size, localization, and blood supply. However, some textbooks provide a general anatomical description of the thyroid gland of domestic carnivores. Thus, specific details of the feline gland are missing. The present study aimed to investigate the dimensions, topography, and arterial supply of the thyroid gland in Brazilian shorthair cats and, therefore, provide additional data to diagnose and treat feline thyroid diseases. Thirty Brazilian shorthair cats formalin-fixed cadavers (15 male and 15 female) were injected with red-stained latex solution by a canula in the thoracic aorta. The necropsy unit of the Rural Federal University of Rio de Janeiro donated the specimens. The study included only adult animals with no history of thyroid disease. After the fixation period, the cadavers were dissected to investigate the measurements (length, width at cranial and caudal poles, and thickness), topography, and in situ arterial supply of the thyroid lobes. The mean measurements of the length, cranial pole width, caudal pole width, and thickness in the right lobe were 19.39 ± 3.10 mm, 5.36 ± 1.40 mm, 3.67 ± 0.93 mm, and 1.30 ± 0.29 mm, respectively; and 20.29 ± 3.35 mm, 4.85 ± 1.58 mm, 3.88 ± 0.91 mm, 1.64 ± 0.65 mm in the left lobe, respectively. There were no statistical differences (P > 0.05) in the comparison of the measures between sexes or antimers (sides). Pearson's linear correlation detected a positive, moderate (r = 0.55), and significant (P < 0.05) correlation between the right and left lobe lengths. In 70% of the cats, both left and right lobes had the cranial poles located at the same level. Typically, the lobes extended between the first to the eighth tracheal ring. However, the cranial pole of some lobes located as cranially as the cricoid cartilage level, and the caudal pole as caudally as the 12th tracheal ring. Fifty-six percent of the cats had a ventrally located isthmus. In all the sampling, one single thyroid artery emerged as a branch of the common carotid artery and provided branches directly to the thyroid lobe, isthmus and the adjacent muscles and esophagus. Besides establishing average dimensions of normal thyroid lobes in Brazilian shorthair cats, this study detected no significant difference between the average measurements of right and left lobes. Also, a positive linear correlation between the length and width of the right and left lobes became evident. Therefore, the practitioner must consider suspicious any length asymmetry between right and left thyroid lobes until further endocrine test proves otherwise. Most of the cats had the right and left thyroid lobe positioned at the same transversal level; however, positional asymmetries are not uncommon. Unlike dogs, Brazilian shorthair cats have only a single artery to supply each lobe: the thyroid artery. In a feline thyroidectomy, the surgeon must avoid blindly ligating the thyroid artery since this vessel also provided numerous branches to adjacent muscles and esophagus. In a bilateral thyroidectomy, the ventral region between lobes should be thoroughly inspected for the common presence of an isthmus. Sometimes, the surgeon may need to extend the incision caudally beyond the 12th tracheal ring level to visualize the gland tissue entirely.(AU)

Thyroidectomy with parathyroid implantation: is it an easy technique?

Background: Feline hyperthyroidism is the most common endocrine disorder in cats. Cats may not reach the diseasecontrol and/or have side effects with medical therapy. Thyroidectomy is a definitive treatment and the only option whenradioactive iodine is not available. Extracapsular thyroidectomy with transplantation of the external parathyroid gland isthe surgical technique that minimizes the risk of postoperative hypocalcemia when it is compared to others. The aim ofthis study is report the difficulty in visualizing parathyroid gland during extracapsular thyroidectomy with transplantationof the external parathyroid gland technique in hyperthyroid cats.Materials, Methods & Results: Thirty hyperthyroid cats were evaluated and submitted to extracapsular thyroidectomywith transplantation of the external parathyroid gland. Blood samples were collected to hematologic, biochemical andhormonal (total thyroxine) analysis. On physical examination, at least one cervical thyroid lobe was palpable. Cats weretreated with methimazole. Thyroidectomy was recommended when adverse effects of medication occurred or medicalhormonal stabilization was not achieved. The excised thyroid and a sample of external parathyroid gland were histologically examined. Thirteen castrated males and seventeen spayed female cats in age ranging from eight to nineteen years(mean age 13.3 years) were indicated to surgery. Twenty three cats were Brazilian domestic short hair, six were Siameseand one was Oriental. Thyroid palpable cervical nodule was unilateral in eight cats and bilateral in twenty two cats. Thereasons for surgery included adverse effects of methimazole (14/30), difficulty in medicating, owners interest in surgicaltreatment (6/30) and inability to stabilize with medical management (10/30). None developed any anesthetic or postoperative complications. The...(AU)

Thyroidectomy with parathyroid implantation: is it an easy technique?

Background: Feline hyperthyroidism is the most common endocrine disorder in cats. Cats may not reach the diseasecontrol and/or have side effects with medical therapy. Thyroidectomy is a definitive treatment and the only option whenradioactive iodine is not available. Extracapsular thyroidectomy with transplantation of the external parathyroid gland isthe surgical technique that minimizes the risk of postoperative hypocalcemia when it is compared to others. The aim ofthis study is report the difficulty in visualizing parathyroid gland during extracapsular thyroidectomy with transplantationof the external parathyroid gland technique in hyperthyroid cats.Materials, Methods & Results: Thirty hyperthyroid cats were evaluated and submitted to extracapsular thyroidectomywith transplantation of the external parathyroid gland. Blood samples were collected to hematologic, biochemical andhormonal (total thyroxine) analysis. On physical examination, at least one cervical thyroid lobe was palpable. Cats weretreated with methimazole. Thyroidectomy was recommended when adverse effects of medication occurred or medicalhormonal stabilization was not achieved. The excised thyroid and a sample of external parathyroid gland were histologically examined. Thirteen castrated males and seventeen spayed female cats in age ranging from eight to nineteen years(mean age 13.3 years) were indicated to surgery. Twenty three cats were Brazilian domestic short hair, six were Siameseand one was Oriental. Thyroid palpable cervical nodule was unilateral in eight cats and bilateral in twenty two cats. Thereasons for surgery included adverse effects of methimazole (14/30), difficulty in medicating, owners’ interest in surgicaltreatment (6/30) and inability to stabilize with medical management (10/30). None developed any anesthetic or postoperative complications. The...

Osteossarcoma osteoblástico primário em glândula tireoide de cão da raça rotweiller - relato de caso / Primary osteoblastic osteosarcoma in the thyroid gland of a rottweiler - a case report / Osteosarcoma osteoblástico primario de tiroides en Rottweiler - relato de caso

Osteossarcoma extraesquelético em cães é um tipo raro de câncer ósseo,com capacidade de acometer outros órgãos e tecidos epiteliais. Este estudotem como objetivo relatar o caso de um cão macho da raça rotweiller comosteossarcoma extraesquelético em glândula tireoide e evolução de três meses, desde a sua manifestação clínica. Durante a consulta , foi realizada radiografia do pescoço para avaliar a extensão do tumor. Foram feitas também radiografia do tóraxe ultrassonografia abdominal, sendo ambas negativas para metástase. O material do tumor foi colhido por citologia aspirativa, sendo sugestivo para osteossarcoma. Após 25 dias, o paciente foi submetido ao procedimento cirúrgico para tireoidectomia total; no entanto, veio a óbito após o término da cirurgia, devido a complicaçõescardio/respiratórias. Foi realizada a necropsia, sendo constatada a presença de nódulos na pleura e no pulmão compatíveis com metástase. O diagnóstico foi confirmado posteriormente por meio do exame histopatológico, o que caracterizou um quadro raro de câncer em cães.

Extraskeletal osteosarcoma is a rare type of bone cancer in dogs, and canaffect other organs and epithelial tissues. This study reports the case of a male rottweiler presenting a three-month history of extraskeletal osteosarcoma in the thyroid gland. Neck radiography was performed to assess tumor extension, as well as chest and abdominal ultrasonography, which were negative for metastasls . Aspirationcytology of tumor material was suggestive of osteosarcoma. After 25 days, the patient underwent total thyroidectomy, but passed away after surgery completion due to cardiorespiratory complications. Necropsy confirmed the presence of nodules in the pleura and lung that were consistent with metastasis. Histopatholoqical examinationlater confirmed the diagnosis of a rare case of cancer in dogs.

El osteosarcoma extraesquelético del perro es un tipo raro de cânceróseo, que puede afectar otros órganos y tejidos epiteliates. Este trabajo tiene como objetivo relatar el caso de un perro macho de raza Rottweiler que presento un osteosarcoma extraesquelético en la glándula tiroides con evolución de tres mesesdesde su manifestación clínica. Durante la consulta se realizó una radiografia delcuello a fin de evaluar la extensión del tumor. Se realizaron también radiografías de tórax y ecografía abdominal, aunque ambos exámenes fueron negativos en relacióna la presencia de metástasis. Se realizó una punción aspirativa, y el material enviado para examen fue sugestivo de osteosarcoma. Veinticinco días después el paciente entró en cirugía, en la que se realizó una tiroidectomía total. No obstante, el mismo murió después del procedimiento quirúrgico debido a complicaciones cardiorrespiratorias.En la necropsia se pudo comprobar la presenda de nódulos en la pleura y en el pulmón compatibles con metástasis. El diagnóstico se comprobó por exámenes histopatológicos, confirmando la presencia de un cuadro raro de cáncer en perros.

Osteossarcoma osteoblástico primário em glândula tireoide de cão da raça rotweiller - relato de caso / Primary osteoblastic osteosarcoma in the thyroid gland of a rottweiler - a case report / Osteosarcoma osteoblástico primario de tiroides en Rottweiler - relato de caso

Osteossarcoma extraesquelético em cães é um tipo raro de câncer ósseo,com capacidade de acometer outros órgãos e tecidos epiteliais. Este estudotem como objetivo relatar o caso de um cão macho da raça rotweiller comosteossarcoma extraesquelético em glândula tireoide e evolução de três meses, desde a sua manifestação clínica. Durante a consulta , foi realizada radiografia do pescoço para avaliar a extensão do tumor. Foram feitas também radiografia do tóraxe ultrassonografia abdominal, sendo ambas negativas para metástase. O material do tumor foi colhido por citologia aspirativa, sendo sugestivo para osteossarcoma. Após 25 dias, o paciente foi submetido ao procedimento cirúrgico para tireoidectomia total; no entanto, veio a óbito após o término da cirurgia, devido a complicaçõescardio/respiratórias. Foi realizada a necropsia, sendo constatada a presença de nódulos na pleura e no pulmão compatíveis com metástase. O diagnóstico foi confirmado posteriormente por meio do exame histopatológico, o que caracterizou um quadro raro de câncer em cães.(AU)

Extraskeletal osteosarcoma is a rare type of bone cancer in dogs, and canaffect other organs and epithelial tissues. This study reports the case of a male rottweiler presenting a three-month history of extraskeletal osteosarcoma in the thyroid gland. Neck radiography was performed to assess tumor extension, as well as chest and abdominal ultrasonography, which were negative for metastasls . Aspirationcytology of tumor material was suggestive of osteosarcoma. After 25 days, the patient underwent total thyroidectomy, but passed away after surgery completion due to cardiorespiratory complications. Necropsy confirmed the presence of nodules in the pleura and lung that were consistent with metastasis. Histopatholoqical examinationlater confirmed the diagnosis of a rare case of cancer in dogs.(AU)

El osteosarcoma extraesquelético del perro es un tipo raro de cânceróseo, que puede afectar otros órganos y tejidos epiteliates. Este trabajo tiene como objetivo relatar el caso de un perro macho de raza Rottweiler que presento un osteosarcoma extraesquelético en la glándula tiroides con evolución de tres mesesdesde su manifestación clínica. Durante la consulta se realizó una radiografia delcuello a fin de evaluar la extensión del tumor. Se realizaron también radiografías de tórax y ecografía abdominal, aunque ambos exámenes fueron negativos en relacióna la presencia de metástasis. Se realizó una punción aspirativa, y el material enviado para examen fue sugestivo de osteosarcoma. Veinticinco días después el paciente entró en cirugía, en la que se realizó una tiroidectomía total. No obstante, el mismo murió después del procedimiento quirúrgico debido a complicaciones cardiorrespiratorias.En la necropsia se pudo comprobar la presenda de nódulos en la pleura y en el pulmón compatibles con metástasis. El diagnóstico se comprobó por exámenes histopatológicos, confirmando la presencia de un cuadro raro de cáncer en perros.(AU)

Causas de hipertireoidismo em gatos submetidosa tireoidectomia / Causes of hyperthyroidism in cats submitted to thyroidectomy

O hipertireoidismo é a doença endócrina mais comum em gatos e geralmente é causada por adenomatireoidiano. O tratamento pode ser clínico, cirúrgico ou por radioiodoterapia. Vinte e quatro gatoscom hipertireoidismo e nódulos cervicais palpáveis, independente da raça, sexo, idade ou raça, foramsubmetidos ao tratamento cirúrgico. O histórico, anamnese, examesclínico e laboratoriais foramrealizados. Os pacientes foram estabilizados com medicação oral e submetidos àtireoidectomia comimplantação da glândula paratireóide no músculo esterno-hióideo. Os gatos eram de meia-idade aidosos, não havendo predisposição de sexo ou raça, sendo dezoito sem raça definida, quatro siameses,um Oriental e um persa. A glândula paratireóide foi implantada em 12 animais pela dificuldade dalocalização da mesma. Nenhum animal desenvolveu complicação pós-operatória. A histopatologiaidentificou vinte e três animais com adenoma tireoidiano e um com carcinoma. A cirurgia é seguracomo tratamento para hipertireoidismo em gatos sem complicações pós-operatórias. O adenoma é acausa mais comum de hipertireoidismo em gatos.(AU)

Hyperthyroidism is the most common endocrine disease in cats andis usually caused by thyroidadenoma.It can be treatedby clinical, surgical or radioiodinetreatment. Twenty four cats with hyperthyroidismwith palpable thyroid lobes in the neck underwent surgical treatment, regardless of sex,age, or breed.The history, anamnesis, general clinical examination and laboratory tests were performed.Animals were stabilized by oral medication and submitted to thyroidectomy with parathyroidgland transplantation in sternohyoid muscle. The animals were middle-aged to elderly, with no genderpredilection, and there were eighteen Domestic Shorthairs, four Siamese cats, one Persian andone Oriental. The parathyroid gland was transplanted in only twelve animals because in the others itwas not identified. No animal developed postoperative complications.Histopathology of the twentythree animals showed presence of thyroid adenoma and one carcinoma. Surgery is safe asa definitivetreatment for hyperthyroidism in hyperthyroid cats without serious complications. Adenoma is themost important cause of hyperthyroidism in cats.(AU)

Causas de hipertireoidismo em gatos submetidosa tireoidectomia / Causes of hyperthyroidism in cats submitted to thyroidectomy

O hipertireoidismo é a doença endócrina mais comum em gatos e geralmente é causada por adenomatireoidiano. O tratamento pode ser clínico, cirúrgico ou por radioiodoterapia. Vinte e quatro gatoscom hipertireoidismo e nódulos cervicais palpáveis, independente da raça, sexo, idade ou raça, foramsubmetidos ao tratamento cirúrgico. O histórico, anamnese, examesclínico e laboratoriais foramrealizados. Os pacientes foram estabilizados com medicação oral e submetidos àtireoidectomia comimplantação da glândula paratireóide no músculo esterno-hióideo. Os gatos eram de meia-idade aidosos, não havendo predisposição de sexo ou raça, sendo dezoito sem raça definida, quatro siameses,um Oriental e um persa. A glândula paratireóide foi implantada em 12 animais pela dificuldade dalocalização da mesma. Nenhum animal desenvolveu complicação pós-operatória. A histopatologiaidentificou vinte e três animais com adenoma tireoidiano e um com carcinoma. A cirurgia é seguracomo tratamento para hipertireoidismo em gatos sem complicações pós-operatórias. O adenoma é acausa mais comum de hipertireoidismo em gatos.

Hyperthyroidism is the most common endocrine disease in cats andis usually caused by thyroidadenoma.It can be treatedby clinical, surgical or radioiodinetreatment. Twenty four cats with hyperthyroidismwith palpable thyroid lobes in the neck underwent surgical treatment, regardless of sex,age, or breed.The history, anamnesis, general clinical examination and laboratory tests were performed.Animals were stabilized by oral medication and submitted to thyroidectomy with parathyroidgland transplantation in sternohyoid muscle. The animals were middle-aged to elderly, with no genderpredilection, and there were eighteen Domestic Shorthairs, four Siamese cats, one Persian andone Oriental. The parathyroid gland was transplanted in only twelve animals because in the others itwas not identified. No animal developed postoperative complications.Histopathology of the twentythree animals showed presence of thyroid adenoma and one carcinoma. Surgery is safe asa definitivetreatment for hyperthyroidism in hyperthyroid cats without serious complications. Adenoma is themost important cause of hyperthyroidism in cats.

Tireoidectomia extracapsular com transplante de paratireóide em felino - Relato de caso / Feline Extracapsular Thyroidectomy with Parathyroid Gland Tranplantation - Case

O presente relato descreve um caso de hipertireoidismo felino em um paciente, macho, com 16 anos,que apresentava como sinais clínicos principais emaciação, polifagia e vômitos. O animal inicialmentefoi tratado com metimazol, porém apresentou sinais de intoxicação ao medicamento, com episódioseméticos graves. O felino foi submetido, então, a tireoidectomia extracapsular com transplante de paratireóide,uma técnica que promove a cura do animal sem, no entanto, acarretar complicações comoa hipocalcemia(AU)

This report describes a case of hyperthyroidism in a male 16 years old cat, whose mainly symptomswere weight loss, polyphagia and vomiting. The animal was treated with methimazole. Nevertheless,the cat presented signs of intoxication due to medication, with severe emetic episodes. The catundergone to surgery with extracapsular thyroidectomy technique associated with transplantation ofparathyroid gland. This technique promotes cure without complications such as hypocalcaemia(AU)

Tireoidectomia extracapsular com transplante de paratireóide em felino - Relato de caso / Feline Extracapsular Thyroidectomy with Parathyroid Gland Tranplantation - Case

O presente relato descreve um caso de hipertireoidismo felino em um paciente, macho, com 16 anos,que apresentava como sinais clínicos principais emaciação, polifagia e vômitos. O animal inicialmentefoi tratado com metimazol, porém apresentou sinais de intoxicação ao medicamento, com episódioseméticos graves. O felino foi submetido, então, a tireoidectomia extracapsular com transplante de paratireóide,uma técnica que promove a cura do animal sem, no entanto, acarretar complicações comoa hipocalcemia

This report describes a case of hyperthyroidism in a male 16 years old cat, whose mainly symptomswere weight loss, polyphagia and vomiting. The animal was treated with methimazole. Nevertheless,the cat presented signs of intoxication due to medication, with severe emetic episodes. The catundergone to surgery with extracapsular thyroidectomy technique associated with transplantation ofparathyroid gland. This technique promotes cure without complications such as hypocalcaemia

Aspectos funcionais e imunológico do transplante autólogo da tireóide em ratos

Purpose: To study the hormonal production of the thyroid transplanted into the mesenteric fatty tissue. Methods: Forty-two Wistar rats were used, 30 in the experimental group and 12 as controls, to test survival after 100 days of transplantation. Half of the thyroid was removed and implanted into the mesenteric tissue. Ten days later the half of the gland left in situ was removed. Levels of thyroid hormones were measured at several different periods after transplantation, in serum from peripheral blood. Removed tissue was submitted to histological, morphometric and ultrastructural analysis. Results: Morphologic studies were within normal limits. . The T3 and T4 hormones maintained their normal levels. TSH levels showed marked elevation, which subsided around the 75 day of transplantation, but remained elevated during the entire experimental period. Levels of gamma-globulin remained within normal limits. Conclusion: Levels of T3 and T4 reflected the preservation of good thyroid function during mesenteric transplantation. The increased TSH levels revealed pituitary stimulation to a reduced amount of thyroid tissue. The autologous implantation of thyroid tissue is thus feasible and safe.

Objetivo: Investigar a produção dos hormônios da tireóide transplantada no mesentério. Métodos: Foram operados quarenta e dois ratos Wistar, distribuídos em três grupos. No grupo 1, 30 ratos dos quais colheu-se o sangue para dosagem dos hormônios. O lobo esquerdo da tireóide do rato foi dividido em dois fragmentos e transplantados para o mesentério. O implante foi removido do mesentério e encaminhado para análise histológica e morfométrica. O grupo 2, com 10 ratos, para testar a sobrevivência dos animais somente com os implantes por cem dias, isto é sem a tireóide in situ. Grupo 3, com 2 animais para o estudo do enxerto à microscopia eletrônica. Resultados: A histologia, a morfometria e a microscopia eletrônica revelram o tecido enxertado nos limites da normalidade, bem como os hormônios T3 e T4. O TSH esteve bastante alto, mas no fim do período de 75 dias, houve um declínio em direção ao valor referencial, porém se manteve aumentado. A imunogamaglobulina não sofreu alteração. Conclusão: Os hormônios T3 e T4 refletem a regularidade do tecido tireóideo transplantado na raiz do mesentério. O TSH se mantém aumentado e a imunogamaglobulina sem alteração estatisticamente significante. É possível fazer com segurança o transplante experimental autólogo da tireóide.