Thyroid gland organogenesis results in an organ the shape, size, and position of which are largely conserved among adult individuals of the same species, thus suggesting that genetic factors must be involved in controlling these parameters. In humans, the organogenesis of the thyroid gland is often disturbed, leading to a variety of conditions, such as agenesis, ectopy, and hypoplasia, which are collectively called thyroid dysgenesis (TD). The molecular mechanisms leading to TD are largely unknown. Studies in murine models and in a few patients with dysgenesis revealed that mutations in regulatory genes expressed in the developing thyroid are responsible for this condition, thus showing that TD can be a genetic and inheritable disease. These studies open the way to a novel working hypothesis on the molecular and genetic basis of this frequent human condition and render the thyroid an important model in the understanding of molecular mechanisms regulating the size, shape, and position of organs.

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Thyroid development and its disorders: genetics and molecular mechanisms.

Cervical cancer is one of the most common cancers in women worldwide The outcome of patients with metastatic cervical cancer is poor We reviewed the relevant literature concerning the treatment and diagnosis of metastatic cervical cancer There are two types of metastasis related to different treatments and survival rates: hematogenous metastasis and lymphatic metastasis Patients with hematogenous metastasis have a higher risk of death than those with lymphatic metastasis In terms of diagnosis, fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) and PET-computed tomography are effective tools for the evaluation of distant metastasis Concurrent chemoradiotherapy and subsequent chemotherapy are well-tolerated and efficient for lymphatic metastasis As for lung metastasis, chemotherapy and/or surgery are valuable treatments for resistant, recurrent metastatic cervical cancer and chemoradiotherapy may be the optimal choice for stage IVB cervical cancer Chemotherapy and bone irradiation are promising for bone metastasis A better survival is achieved with multimodal therapy Craniotomy or stereotactic radiosurgery is an optimal choice combined with radiotherapy for solitary brain metastases Chemotherapy and palliative brain radiation may be considered for multiple brain metastases and other organ metastases

/pdf/advances-in-diagnosis-and-treatment-of-metastatic-cervical-exkg73faho.pdf

Advances in diagnosis and treatment of metastatic cervical cancer

Thyroid dysgenesis (TD) is responsible for most cases of congenital hypothyroidism, a condition that affects about one in 4000 newborns. Mutations in PAX8, TITF1, or FOXE1 may account for congenital hypothyroidism in patients with either isolated TD or TD with associated malformations involving kidney, lung, forebrain, and palate. Pax8, titf1, and foxe1 are expressed in the mouse thyroid bud as soon as it differentiates on the pharyngeal floor. Because the spatio-temporal expression of these genes is unknown in humans, we decided to study them at different stages of human embryonic and fetal development. PAX8 and TITF1 were first expressed in the median thyroid primordium. Interestingly, PAX8 was also expressed in the thyroglossal duct and the ultimobranchial bodies. Human FOXE1 expression was detected later than in the mouse. PAX8 was also expressed in the developing central nervous system and kidney, including the ureteric bud and the main collecting ducts. TITF1 was expressed in the ventral forebrain and lung. FOXE1 expression was detected in the oropharyngeal epithelium and thymus. In conclusion, the expression patterns described here show some differences from those reported in the mouse. They explain the malformations associated with TD in patients carrying PAX8, TITF1, and FOXE1 gene mutations.

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PAX8, TITF1, and FOXE1 gene expression patterns during human development: new insights into human thyroid development and thyroid dysgenesis-associated malformations.

Congenital hypothyroidism is the most common congenital endocrine disorder (one newborn in 3000) and represents the most common cause of preventable mental retardation. In 10-20% of cases, it is due to autosomal recessive functional disorders leading to goiter formation (thyroid dyshormonogenesis). In the remainder, it is due to thyroid dysgenesis, which comprises usually isolated defects in: (1) migration of the median thyroid anlage, leading to a round cluster of ectopic cells (usually in a sublingual position) with no other thyroid tissue present; (2) differentiation or survival of the thyroid follicular cells leading to athyreosis; and (3) growth of a thyroid with the normal bilobed shape and in the normal cervical position (orthotopic hypoplasia). Mouse knock-outs have demonstrated that thyroid transcription factor-1 (TTF-1) and PAX8 are required for the survival and proliferation of thyroid follicular cell precursors, TTF-2 for their downward migration and the thyrotropin receptor (TSHR) for post-natal thyroid growth. In humans, thyroid dysgenesis is generally a sporadic malformation but an affected relative is found in 2% of cases, a figure 15-fold higher than by chance alone. Pedigree analysis is most compatible with dominant inheritance with variable penetrance. However, mutations in TTF-1, TTF-2, PAX8 and TSHR are found in 90% of monozygotic twin pairs suggests that isolated thyroid ectopy or athyreosis most often results from early somatic mutations, epigenetic modifications or stochastic developmental events.

Development of the thyroid gland: lessons from congenitally hypothyroid mice and men

Corresponding Authors: Ibrahim NA, Department of Surgery, Lagos State University, College of Medicine and Lagos State University Teaching, Hospital, P.M.B. 21266, Ikeja, Lagos, Nigeria, E-mail: ibrahimakanmu@yahoo.com Received 03-08-11, Revised 10-09-11, Accepted 25-09-11

/pdf/ectopic-thyroid-etiology-pathology-and-management-2zxinhaqmh.pdf

Ectopic thyroid: etiology, pathology and management.

Ectopic thyroid glands generally appear in the midline due to abnormal median migration; their presence lateral to the midline is rare. We report the case of a 42-year-old female who presented with symptoms of thyrotoxicosis and an expanding submandibular swelling. Tc-99m-sodium pertechnetate scanning showed thyroid tissue in the left submandibular region, while no thyroid tissue was seen in the normal site. The patient was treated with 10 mCi of 131I and subsequently became euthyroid. Literature review revealed seven cases of lateral aberrant thyroid tissue. The theories to explain lateral aberrant thyroid are presented.

Thyrotoxicosis in a Patient with Submandibular Thyroid

Dual ectopic thyroid glands rarely occur, and only six cases have been reported in the literature. The authors describe a 14-year-boy who had a midline neck swelling for 8 to 9 years. The swelling increased gradually, but he had no pressure symptoms. The thyroid hormone profile showed a moderately increased thyroid-stimulating hormone value and normal T3 and T4 levels. A Tc-99m sodium pertechnetate thyroid scan showed dual ectopic thyroid glands in the sublingual and subhyoid regions.

Dual thyroid ectopy: case report and review of the literature.

A 53-year-old man was found serendipitously to have increased blood-pool uptake in the right lobe of the thyroid during a radionuclide ventriculography study for left ventricular function. Primary thyroid hemangioma is a rare condition, with only two cases reported in the literature. Secondary hemangioma may occur as a result of fine-needle aspiration. This technique may cause hematoma formation, which generally resolves normally, but on rare occasions it can lead to cavernous hemangioma formation. In patients with a thyroid swelling who have a cold nodule on a thyroid scan and only blood on repeated fine-needle aspiration, Tc-99m erythrocyte blood-pool imaging may be performed to diagnose hemangioma.

Thyroid hemangioma: a case report with a review of the literature.

Aim Bone metastasis in cervical cancer is rare. With the aim of defining the frequency of bony metastasis in patients of carcinoma cervix, with clinical suspicion of metastasis, we performed bone scan in 38 such patients. Results Twelve out of the 38 patients were confirmed as having metastasis. All the patients were also detected by bone scan (100% sensitivity). Conclusion Bone scan should be investigation of choice for screening patients of carcinoma cervix with symptoms suggestive of metastasis in all stage of the disease. Bone scan is the most sensitive method for detection of bone metastasis. Bone scan offers the additional advantages of allowing a review of the kidney size to look for ureteric involvement and subsequent hydronephrosis.

Bone scanning for bone metastasis in carcinoma cervix.

https://jnm.snmjournals.org/content/jnumed/41/6/1120.1.full.pdf

Shikha Khullar

Papers

Thyrotoxicosis in a Patient with Submandibular Thyroid

Dual thyroid ectopy: case report and review of the literature.

Thyroid hemangioma: a case report with a review of the literature.

Bone scanning for bone metastasis in carcinoma cervix.

99mTc-tetrofosmin scintigraphy in management of pulmonary tuberculosis.