Cystic ectopic lingual thyroid tissue in a male cat

CASE DESCRIPTION-A 6-year-old neutered male cat was examined because of a 4-week history of abnormal sounds while drinking and a previously noted mass at the base of the tongue. CLINICAL FINDINGS-Oral examination revealed a 1-cm-diameter midline cystic mass on the dorsal aspect of the base of the tongue at the junction of the rostral two-thirds and caudal third of the tongue. Complete blood count and serum biochemical analysis revealed no clinically relevant abnormalities, and serum total thyroxine and free thyroxine (determined by equilibrium dialysis) concentrations were within the reference range. TREATMENT AND OUTCOME-The fluid in the cystic mass was aspirated, and the remaining deflated mass was marsupialized. Histologic and immunohistochemical examination of sections of the excised mass revealed ectopic thyroid tissue. The cat recovered uneventfully from the surgery, clinical signs resolved, and the cat remained euthyroid with no recurrence of the mass as of 8 months after surgery. CLINICAL RELEVANCE-This is the first known reported case of ectopic lingual thyroid tissue in a male cat. In humans, the most common site of ectopic thyroid tissue is at the base of the tongue and the condition is disproportionately found in females, compared with males. In humans with ectopic lingual thyroid tissue, the patient often lacks any other functional thyroid tissue. However, the cat of this report remained euthyroid after mass resection.     

Overexpression of c-Ras in hyperplasia and adenomas of the feline thyroid gland: an immunohistochemical analysis of 34 cases

Formalin-fixed, paraffin-embedded thyroid glands from 18 cats diagnosed with hyperthyroidism were evaluated immunohistochemically for overexpression of the products of oncogenes c-ras and bcl2 and the tumor suppressor gene p53. Fourteen thyroid glands from euthyroid cats without histologically detectable thyroid lesions were examined similarly as controls. Results from these investigations showed that all cases of nodular follicular hyperplasia/adenomas stained positively for overexpression of c-Ras protein using a mouse monoclonal anti-human pan-Ras antibody. The most intensely positively staining regions were in luminal cells surrounding abortive follicles. Subjacent thyroid and parathyroid glands from euthyroid cats did not stain immunohistochemically for pan-Ras. There was no detectable staining for either Bc12 or p53 in any of the cats. These results indicated that overexpression of c-ras was highly associated with areas of nodular follicular hyperplasia/adenomas of feline thyroid glands, and mutations in this oncogene may play a role in the etiopathogenesis of hyperthyroidism in cats.     

Intracardiac ectopic thyroid carcinosarcoma in a dog

A 13-year-old spayed female Labrador Retriever with a 1-year history of progressive exercise intolerance was diagnosed with an interventricular mass in the heart via echocardiogram. The animal's general condition progressively declined over the next 8 months, and it was euthanatized. The intracardiac mass, which protruded into the lumen of the right ventricle, was removed at necropsy and fixed in 10% buffered formalin. Histopathologic diagnosis was an ectopic thyroid carcinosarcoma based on the presence of 3 distinct neoplastic tissue types. Intermixed within the tumor were neoplastic thyroid follicles containing colloid and solid nests of thyroid follicular epithelial cells, vascular channels and clefts filled with blood and lined by neoplastic endothelium, and osteoid surrounded by spindle cells and often rimmed by large multinucleated cells. Immunohistochemical reaction for thyroglobulin was positive in the tumor cells forming the colloid-filled follicles and solid nests of epithelial cells. Neoplastic endothelium was positive for factor VIII-related antigen. The thyroid gland was located in its normal anatomic position and was histologically normal, ruling out the possibility that the intracardiac tumor was a metastatic lesion. To the authors' knowledge this is the first reported case of an intracardiac ectopic thyroid carcinosarcoma, and possibly the first ectopic thyroid carcinosarcoma in any location in any species.     

QUALITATIVE AND QUANTITATIVE THYROID IMAGING IN FELINE HYPERTHYROIDISM USING TECHNETIUM-99M AS PERTECHNETATE

Thyroid imaging using technetium-99m as pertechnetate (^99mTcO₄) was carried out in five healthy, euthyroid and 37 hyperthyroid cats using both pinhole and parallel-hole collimators. Images of greater resolution, necessary to distinguish bilateral lobe involvement, were obtained using the pinhole collimator. Per cent thyriod ^99mTcO₄ - uptake was calculated in each cat and was significanly (P < 0.001) higher in hyperthyroid compared with euthyroid cats. In the hyperthyroid cats, per cent thyroid uptake was significantly correlated with serum total thyroxine (T4) and triiodothyronine (T3) Concentrations. Per cent thyroid ^99mTcO₄ - uptake is increased in feline hyperthyrodism and may be calculated using a pinhole collimator alone at the time of qalitative assessment of the extent of thyroid tissue involvement.     

Altered expression of G proteins in thyroid gland adenomas obtained from hyperthyroid cats

OBJECTIVE: To determine whether expression of G proteins (G(i) and G(s)) is altered in thyroid gland adenomas obtained from hyperthyroid cats. SAMPLE POPULATION: Adenomatous thyroid glands obtained from 8 hyperthyroid cats and thyroid glands obtained from 4 age-matched euthyroid cats. PROCEDURE: Expression of G(i) and G(s) was quantified in enriched membrane preparations of thyroid gland tissue, using immunoblotting with G(i) and G(s) antibodies and toxin-catalyzed ADP-ribosylation. RESULTS: Expression of G(i) was significantly reduced in thyroid gland adenomas from hyperthyroid cats, compared with normal thyroid gland tissue from euthyroid cats. Expression of G(s) was similar between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE: A decrease in expression of G in adenomatous thyroid glands of cats may reduce the negative inhibition of the cAMP cascade in thyroid cells, leading to autonomous growth and hypersecretion of thyroxine. Understanding the molecular mechanisms for hyperthyroidism in cats may lead to better treatment or, ultimately, prevention of the disease.     

The effects of thyroid hormones on the skin of beagle dogs

The effects of hypothyroidism on canine skin were determined by comparing morphologic, morphometric, and hair cycle differences in skin biopsy samples from 3 groups of age- and gender-matched Beagle dogs: (1) euthyroid dogs; (2) dogs made hypothyroid by administration of 131I; and (3) dogs made hypothyroid and maintained in a euthyroid state by treatment with synthetic thyroxine. After 10 months of observation, there was slower regrowth of hair 2 months after clipping in the untreated-hypothyroid dogs. Untreated-hypothyroid dogs had a greater number of follicles in telogen and fewer hair shafts (ie, a greater number of hairless telogen follicles) than did the control group. The control dogs had a greater number of telogen follicles but the same number of hair shafts as the treated-hypothyroid group. Treated-hypothyroid dogs had the greatest number of follicles in the growing stage of the hair cycle (anagen). This study suggests that, at least in Beagles, induced hypothyroidism does not affect the pelage as dramatically as has been described in naturally occurring disease. This is because normal Beagles retain hair shafts in follicles for long periods, and the alopecia of hypothyroidism appears to evolve slowly because of the prolongation of this haired telogen stage. The evaluation of thyroxine-treated hypothyroid dogs demonstrates that thyroid hormone supplementation of Beagle dogs with induced hypothyroidism stimulates hair growth.     

Histologic and ultrastructural evaluation of thyroid lesions associated with hypothyroidism in dogs

Thyroid lesions in 16 pet dogs with hypothyroidism were evaluated by light and electron microscopy. Lymphocytic thyroiditis, found in seven dogs, was characterized by diffuse infiltration of the thyroid gland by lymphocytes, plasma cells and macrophages with formation of some lymphoid nodules and destruction of follicles, progressing to replacement of most of the thyroid by fibrous connective tissue. The basement membrane around follicles was thick and had electron-dense deposits. The morphology of the thyroid lesions and the presence of circulating thyroglobulin autoantibodies suggested that lymphocytic thyroiditis was immune-mediated. Idiopathic follicular atrophy, found in nine dogs, was characterized by loss of thyroid parenchyma and replacement by adipose connective tissue. Degeneration of individual follicular cells was present in the early stage, with exfoliation into the colloid and interfollicular area. Most of the thyroid gland consisted of adipose connective tissue with either interspersed small follicles or individual follicular cells that had dilated rough endoplasmic reticulum, large Golgi apparatus, and intracytoplasmic microfollicles in the advanced stage. Follicular atrophy was a degenerative lesion of follicular cells of unknown cause, not associated with inflammatory destruction in the thyroid gland.     

Nodular thyroid hyperplasia in a cynomolgus monkey

Nodular thyroid hyperplasia was found in a 4-year-old male cynomolgus monkey (Macaca fascicularis). The monkey was clinically normal; however, necropsy revealed multiple variably sized nodules in both lobes of the thyroid gland. In contrast to the fairly uniform diameter of the lumen of follicles in the surrounding gland, the diameter of the follicular lumen within the hyperplastic nodules was highly variable and ranged from nonexistent to cystlike. Occasionally, in the larger follicles there were papillary infoldings of epithelium. The hyperplastic nodules were partially encapsulated by a fibrous capsule and showed little compression of the surrounding tissue. The follicular cells and colloid comprising the hyperplastic nodule were immunohistochemically positively stained with the antibody for thyroglobulin. Ultrastructurally, the cells forming follicles had numerous microvilli along the luminal surface, and lysosomal bodies and dilated rough endoplasmic reticulum in the cytoplasm. All these morphologic findings are consistent with nodular thyroid hyperplasia, which is rare in nonhuman primates.     

Perineuronal Nets in the Central Nervous System

The remnant of ultimobranchial (UB) body in the thyroid gland of adult buffalo was studied. This remnant appeared in the form of irregular and elongated follicles of various size and shape with folded lumen. These structures occupied a peripheral location beneath the capsule, as well as being embedded mostly in the vascular connective tissue of the thyroid. Calcitonin cells were predominantly localized in the UB follicles. Scanning electron microscopy revealed that surface of most UB follicular cells was almost flat and polyhedral or hexagonal in shape. Other follicles possessed cells with dome shaped apical surface demarcated by a shallow intercellular depression. The luminal surface of the follicular cell lining was studded with microvilli that appeared with various density and length and were numerous at the cellular borders. Interestingly, most of UB follicular cells were provided with single cilium, projecting over the cell surface. Notably some UB follicles presented various stages of apocrine activities.     

Application of the peroxidase-antiperoxidase procedure to the localization of pituitary hormones and calcitonin in various domestic animals and human beings

Specific cell populations in the pituitary glands of the rat, cat, pig, and human being were positive for thyroid-stimulating hormone (TSH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH). When reacted with prediluted rabbit anti-human TSH, LH, and FSH, antisera were not positive for the demonstration of these hormones in the horse, cow, or dog. Immunocytochemical staining was obtained in the horse, cow, and dog by the use of a primary antiserum against a specific beta-subunit of bovine TSH. The immunocytochemical staining of TSH, LH, FSH, adrenocorticotropic hormone, growth hormone, prolactin, and calcitonin was examined by the peroxidase-antiperoxidase method, using standard commercially available kits. All species examined had a strong positive reaction in specific pituitary cell populations for adrenocorticotropic hormone, growth hormone, and prolactin. Sections of normal thyroid gland tissue had positive staining of C cells containing calcitonin at the dilution of 1:100 of the primary antibody in the rat, horse, cow, dog, cat, pig, and human being.     

芦荟大黄素对衰老蛋鸡卵泡氧化应激的缓解作用

旨在提高衰老蛋鸡的产蛋量,蛋鸡腹腔注射10 mg·kg^-1芦荟大黄素,每天1次,连续7 d,研究天然的芦荟大黄素对580日龄(D580)衰老蛋鸡卵巢重量、卵泡数量和体重变化的影响。本试验建立D-gal诱导的衰老卵泡模型,探究芦荟大黄素对卵泡衰老过程中抗氧化能力、细胞凋亡和增殖的影响,然后检测芦荟大黄素对体外衰老卵泡模型中Nrf2/HO-1信号通路相关蛋白和基因表达水平的影响,以及Nrf2激活剂和阻断剂对芦荟大黄素引起的衰老卵泡氧化应激缓解作用的变化。结果表明,芦荟大黄素处理可提高各级卵泡的数量(P < 0.05),其中,大黄卵泡、小黄卵泡、大白卵泡和小白卵泡数量分别提高32.00%、34.62%、50.00%和54.21%。同时,芦荟大黄素处理使D580蛋鸡血清中雌二醇(E₂)和孕酮(P₄)水平分别提高34.14%和680.00%。芦荟大黄素处理还可提高卵泡中雌激素受体(ERα和ERβ)和肝中甘油三酯(triglyceride, TG)的含量(P < 0.05)。D580蛋鸡肝组织中脂肪酸合成相关基因的转录水平显著下调,但芦荟大黄素处理可提升这些基因的转录水平。此外,芦荟大黄素通过提高卵泡抗氧化酶的活性、Nrf2/HO-1信号通路相关蛋白和基因的表达,缓解自然衰老和D-gal诱导的衰老卵泡的氧化应激。芦荟大黄素处理可促进衰老卵泡细胞增殖,抑制其凋亡。综上表明,芦荟大黄素通过激活Nrf2/HO-1信号通路缓解蛋鸡卵泡的氧化应激,提升蛋鸡衰老过程中卵泡雌激素受体基因和肝卵黄生成相关基因的表达量、血清E₂和P₄水平、卵泡抗氧化能力以及肝TG合成能力,从而缓解卵泡衰老。     

Surface Ultrastructure of Ultimobranchial Remnants in the Thyroid Gland of Buffalo (Bos bubalis)

The remnant of ultimobranchial (UB) body in the thyroid gland of adult buffalo was studied. This remnant appeared in the form of irregular and elongated follicles of various size and shape with folded lumen. These structures occupied a peripheral location beneath the capsule, as well as being embedded mostly in the vascular connective tissue of the thyroid. Calcitonin cells were predominantly localized in the UB follicles. Scanning electron microscopy revealed that surface of most UB follicular cells was almost flat and polyhedral or hexagonal in shape. Other follicles possessed cells with dome shaped apical surface demarcated by a shallow intercellular depression. The luminal surface of the follicular cell lining was studded with microvilli that appeared with various density and length and were numerous at the cellular borders. Interestingly, most of UB follicular cells were provided with single cilium, projecting over the cell surface. Notably some UB follicles presented various stages of apocrine activities.     

Percutaneous ultrasound-guided radiofrequency heat ablation for treatment of hyperthyroidism in cats

OBJECTIVE: To determine efficacy and safety of percutaneous radiofrequency heat ablation for treatment of hyperthyroidism in cats. DESIGN: Prospective study. ANIMALS: 9 cats. PROCEDURE: Hyperthyroidism was diagnosed via clinical signs and high serum total (TT4) and free thyroxine (fT4) concentrations. One or 2 hyperfunctional cervical thyroid nodules were detected by use of scintigraphy and ultrasonography. If cats had 1 abnormal thyroid lobe, heat ablation was performed on that lobe; if cats had 2 abnormal lobes, heat ablation was applied to the larger lobe. Overall, heat ablation was performed 14 times in the 9 cats. Clinical signs and serum TT4, fT4, and calcium concentrations were monitored daily for 2 days after the procedure, weekly for the first month, and then monthly. Laryngeal function was evaluated and cervical ultrasonography and thyroid scintigraphy were also performed. Monitoring continued for as long as 9 months after heat ablation if a cat became euthyroid or until an owner chose an alternative treatment because of recurrence of hyperthyroidism. RESULTS: Serum TT4 and fT4 concentrations transiently decreased after all 14 heat ablation procedures (< or = reference range after 10 of 14 treatments) within 2 days after the procedure. Cats were euthyroid for 0 to 18 months (mean, 4 months). Hyperthyroidism recurred in all cats. Adverse effects included transient Horner's syndrome (2 cats) and laryngeal paralysis without clinical signs (1 cat). CONCLUSIONS AND CLINICAL RELEVANCE: Percutaneous heat ablation as a treatment for hyperthyroidism in cats is effective transiently but not permanently.     

Ultrasonographic evaluation of the thyroid gland in healthy, hypothyroid, and euthyroid Golden Retrievers with nonthyroidal illness

Ultrasound evaluation of the thyroid gland was performed in healthy, hypothyroid, and euthyroid Golden Retriever dogs with nonthyroidal illness (NTI) to determine the diagnostic usefulness of ultrasound for differentiating between euthyroid and hypothyroid dogs. Thirty-six healthy, 11 hypothyroid, and 35 euthyroid dogs with NTI were evaluated. Each thyroid lobe was examined ultrasonographically for size, shape, echogenicity, and homogeneity. Thyroid lobe volume was estimated by using the equation for an ellipsoid: pi/6(length X height x width). No differences were found between healthy dogs and euthyroid dogs with NTI. In the majority of euthyroid dogs, the thyroid lobes were fusiform and triangular in shape in longitudinal and transverse planes, respectively. The thyroid capsule appeared smooth. The thyroid parenchyma had a homogeneous echogenic pattern and usually was hyperechoic or isoechoic compared with the surrounding musculature. Ultrasound findings in hypothyroid dogs were more variable, including a greater frequency of round to oval-shaped thyroid lobes in the transverse imaging plane (P < .05), hypoechogenicity of the thyroid parenchyma compared with surrounding musculature (P < .001), and a decrease in the size and volume of the thyroid lobes and total volume of the thyroid gland (P < .05) compared with euthyroid dogs. Other findings in hypothyroid dogs included an irregular surface to the thyroid capsule, a heterogeneous pattern to the thyroid parenchyma, and differences in the echogenic pattern between the left and right thyroid lobes. Results suggest that determination of thyroid size and volume by ultrasound may be a useful adjunctive test for differentiating between hypothyroid and euthyroid dogs with NTI.     

THYROID TO SALIVARY RATIOS DETERMINED BY TECHNETIUM-99M PERTECHNETATE IMAGING IN THIRTY-TWO EUTHYROID CATS

Thyroid to salivary (TS) ratio is the most commonly used scintigraphic parameter for differentiating euthyroid and hyperthyroid cats. Studies to determine the normal TS ratio have been performed in small cat populations. In this study, the TS ratio was determined in 32 cats between 8 and 13 years of age. The study population was documented to be euthyroid based on normal initial and 6-week follow-up serum thyroid concentrations and normal T3 suppression tests. All images were obtained with a low-energy all-purpose collimator between 20 and 40 min after the injection of approximately 111 MBq (3.0 mCi) pertechnetate. Manual regions of interest (ROI) were made of the thyroid and salivary glands of the ventral image A 95% prediction interval based on the natural log of the TS ratio was computed to provide a normal range of 0.48-1.66. This range is similar to previous studies, but suggests a slightly higher upper limit than previously reported.     

Thyroid sonography as an effective tool to discriminate between euthyroid sick and hypothyroid dogs

The diagnosis of canine hypothyroidism and its differentiation from euthyroid sick syndrome still is a major diagnostic challenge. In this study, ultrasonography was shown to be an effective tool for the investigation of thyroid gland diseases. Healthy control dogs (n = 87), dogs with euthyroid sick syndrome (n = 26), thyroglobulin autoantibody-positive (TgAA-positive, n = 30) hypothyroid dogs, and TgAA-negative (n = 23) hypothyroid dogs were examined by thyroid ultrasonography. Maximal cross sectional area (MCSA), thyroid volume, and echogenicity were measured. Statistical analysis identified highly significant (P < .001) differences between euthyroid and hypothyroid dogs both in thyroid volume and in MCSA, whereas no significant differences in thyroid size were detected between healthy euthyroid dogs and dogs with euthyroid sick syndrome. In euthyroid and euthyroid sick dogs, parenchymal echotexture was homogeneous and hyperechoic, whereas relative thyroid echogenicity of both TgAA-positive and TgAA-negative hypothyroid dogs was significantly lower (P < .001). When using arbitrarily chosen cutoff values for relative thyroid volume, MCSA, and echogenicity, thyroid volume especially was found to have highly specific predictive value for canine hypothyroidism. In summary, the data reveal that thyroid sonography is an effective ancillary diagnostic tool to differentiate between canine hypothyroidism and euthyroid sick syndrome.     

Histological, histochemical and immunohistochemical study of the lymph nodes of the one humped camel (Camelus dromedarius)

Prescapular, femoral, mesenteric, mediastinal and splenic lymph nodes from nine camels of one to 12 years of age were studied. There were no obvious structural differences between these different lymph nodes or between the ages. The lymph nodes were surrounded by a capsule formed of two layers, an outer thicker layer of connective tissue and an inner thinner layer mainly of smooth muscles. Trabeculae extended from the inner layer of the capsule dividing the parenchyma characteristically into incomplete lobules. Subcapsular and trabecular lymphatic sinuses were supported by a reticular fiber network. The parenchyma was uniquely different from that of other species, as it was arranged in the form of lymphoid follicles and interfollicular lymphoid tissue. The lymphoid follicles of CD22 positive lymphocytes were supported by a reticular fiber network. This fine network of α-smooth muscle actin positive cells enclosed the lymphoid follicles. The interfollicular tissue was mainly made up of diffusely distributed CD3 positive lymphocytes. MHC class II: DR was expressed by most lymphocytes of the follicles and interfollicular tissue. Lymphatic sinuses and high endothelial venules were found in the interfollicular zone. The lymphatic sinuses were lined by discontinuous endothelial cells. The wall of the high endothelial venules was infiltrated by several lymphocytes and enclosed in a layer of α-smooth muscle actin positive cells. Acid phosphatase positive cells were evenly distributed in the interfollicular zone. A few cells were localized in the lymph follicles. Alkaline phosphatase was observed in the endothelium of the lymphatic sinuses and in the lymphoid follicles.     

A case of canine cutaneous clear cell adnexal carcinoma with prominent expression of smooth muscle actin

Cutaneous clear cell adnexal carcinoma was found in the right lip of a 14-year-old male castrated Shih Tzu. Histologically, the tumor mostly consisted of neoplastic cells with clear or vacuolated cytoplasms and contained frequent tubular structures. Neoplastic cells showed coexpression of pan-cytokeratin (CK) and vimentin by double-labeled immunofluorescence staining. In addition, immunohistochemistry revealed that the tumor cells were positive for pan-CK (AE1/AE3, KL1, CAM 5.2), CK-7, CK-8, CK-14, CK-15, CK-18, vimentin and alpha-smooth muscle actin (SMA) with varied intensity and positivity. Among these marker proteins, SMA was positive in 75% of the tumor cells. On the other hand, CK-15, which is a specific marker of follicular stem cells, was expressed in less than 1% of the tumor cells. Based on these findings, the tumor showed diverse differentiation in apocrine sweat glands and the inner and outer root sheaths of hair follicles, indicating the follicular stem cell to be the origin of this tumor.     

Feline infectious peritonitis presenting as a tumour in the abdominal cavity

This paper describes six cases of feline infectious peritonitis (FIP) in which an abdominal tumour had been suspected clinically. Pathological changes were mainly restricted to the massive enlargement of a mesenteric lymph node due to necrogranulomatous lymphadenitis. FIP was diagnosed on the basis of the immunohistological demonstration of coronavirus antigen in intact macrophages within the necrogranulomatous lesions. In the affected lymph node lymphoid tissue was either almost completely effaced or restricted to follicles composed mainly of variable numbers of blasts. From one to many plasma cells positive for coronavirus-specific antibodies were present in the marginal sinuses or capsules. In addition, necrogranulomas were present in the gut-associated lymphoid tissue of the caecum of one cat, and adjacent to the affected lymph node of another.