Reversibility of thyrotroph hyperplasia after L-thyroxine replacement therapy in patients with juvenile primary hypothyroidism

Pituitary hyperplasia in childhood primary hypothyroidism: a review

INTRODUCTION

Pituitary hyperplasia following primary hypothyroidism in pediatric age group population is considered rare with reports of unnecessary neurosurgical intervention for this medically treatable condition. Given the paucity of information on this topic, it is timely to provide clinicians with a comprehensive summary of available research.

METHODS

A search of published studies in Pubmed, PsychInfo and Cochrane Database with the terms "pituitary hyperplasia" or "pituitary hypertrophy" and "hypothyroidism" was performed and the results filtered for English language, pediatric (0-18 years) population and CT or MRI confirmed findings. 55 studies met the inclusion criteria. Data for a total of 110 patients with pituitary hyperplasia following primary hypothyroidism were extracted. The study population included 29 males and 81 females (M: F= 0.35:1). Patient age varied from 3 weeks to 18 years with a mean age of 10.22 years.

RESULTS

The most common clinical presentations included growth retardation, constipation and features of myxedema which were present in 78, 36 and 18 percent of children included in our review. Neuroimaging showed the mean (SD) pituitary height being 13.48 mm (4.72 mm). All of the patients achieved resolution of their pituitary mass and clinical as well as biochemical abnormalities 1 to 26 months after initiation of thyroid hormone replacement therapy, with an average time interval of 7.22 months. Our review has tried to delve in the pathophysiology as well as clinical, biochemical and radiological aspects of pediatric pituitary hyperplasia secondary to primary hypothyroidism and provide recommendations for treatment and follow-up. This may help anyone concerned gain a substantial knowledge on this topic.

Phenotypic presentation of adolescents with overt primary hypothyroidism

BACKGROUND

The phenotypic presentation of overt hypothyroidism during adolescence is less well characterized. The aim of the study was to study the phenotypic presentation of patients with overt hypothyroidism presenting during adolescence (age 9-18 years).

METHODS

Records of adolescent patients with overt hypothyroidism (thyroid stimulating hormone [TSH]>10 mIU/L) were retrospectively analyzed for presenting complaints, height and pubertal status.

RESULTS

A total of 67 patients (40 females and 37 males, average age 13.2+2.3 years) with a mean TSH of 241.3±336.6 mIU/L were included. The commonest presentation was short stature in 46.2% of patients followed by neck swelling (16.4%) and weight gain (11.9%). The mean height standard deviation score (SDS) was -2.5+2.11, 43% of patients had less than 3 SDS. The height age and bone age were around 3 years less than the chronological age. The bone age significantly correlated with the height age but not with TSH levels. Three patients referred from neurology with primary complaints of headache had pituitary hyperplasia and one presented with hypokalemic periodic paralysis. Seven had delayed puberty and one patient had early periods due to huge ovarian cysts.

CONCLUSIONS

In the present study, severe short stature and uncommon phenotypic presentations were a consequence of long-standing severe untreated hypothyroidism.

Diagnostic approach in children with unusual symptoms of acquired hypothyroidism. When to look for pituitary hyperplasia?

BACKGROUND

Pituitary hyperplasia secondary to primary longstanding hypothyroidism has been reported in the literature in adults and rarely in children.

METHODS

Here we present the clinical presentation and diagnostic procedures in eight children with pituitary hyperplasia due to autoimmune thyroiditis, highlighting common findings, such as growth delay, fatigue or gaining weight, but also exceptional findings such as pericardial effusion, rhabdomyolysis, isolated hypertrichosis, and Van Wyk-Grumbach syndrome, which have rarely or never been described.

RESULTS AND CONCLUSIONS

Surprisingly no thyroid enlargement was detected. We discuss the unusual presenting signs of autoimmune thyroiditis that should raise the suspicion of pituitary hyperplasia. We suggest that a more elaborate clinical assessment and even modification of the diagnostic approach to autoimmune thyroiditis is needed in order to avoid its serious complications.

Endocrine diagnosis and treatment of sellar lesions in pediatric age

INTRODUCTION

Sellar masses are an heterogeneous group of lesions, both in nature and management. Not all of them require surgery.

OBJECTIVES

To describe the presenting symptoms of sellar masses and endocrine abnormalities occurring during follow-up. To emphasize the significance of endocrine assessment, and to identify lesions amenable to hormonal treatment.

PATIENTS AND METHODS

A retrospective review of the records of children under 14 years of age referred to our center for sellar lesions during 12 years. Data collected included sex, age, nature of lesion, clinical presentation, size, treatment, and endocrine abnormalities.

RESULTS

Forty-five patients (25 females) aged 7.2 ± 4.1 years (range 0.25-13.5) were enrolled. Follow-up time was 6.2 ± 3.7 years. Lesion nature was known in 39 cases, 4 of which were successfully treated at the Endocrinology Department: 3 prolactinomas (with dopamine agonist) and one thyrotroph cell hyperplasia (with levothyroxine). The most common presenting symptoms were neurological and/or visual (25/45), followed by endocrine conditions (13/45). Duration of endocrine and neuro-ophthalmic symptoms was 12.6 ± 18.2 months and 2.6 ± 4.9 (P=.012), respectively. Some endocrine condition was found in 24/45 patients at the initial evaluation and in 37/45 patients at the end of follow-up.

CONCLUSIONS

Management of sellar lesions requires a multidisciplinary effort. Endocrine tests are indispensable to identify lesions amenable to hormonal treatment. Endocrine disorders usually occurred before neurological and ophthalmological symptoms, and their identification may therefore allow for earlier diagnosis. Hormone assessment should be regularly performed during follow-up.

Empty sella and primary autoimmune hypothyroidism

In order to assess the association between empty sella (ES) and primary autoimmune hypothyroidism, and the possibility of a common pathogenesis. We retrospectively studied all patients with presumed ES diagnosed in the last 20 years, most of whom were treated by our Endocrinology Department. Subjects with a known etiology were excluded. Incomplete records or those with a doubtful diagnosis were also excluded. A total of 56 subjects were included in the study. ES was diagnosed by pituitary MRI. The measurement of free T4, TSH, and antithyroid antibodies (TPOAb and TgAb) was assayed using commercial kits. The cases of hypothyroidism obtained were compared with those in another group of similar patients, diagnosed with diabetes mellitus type 2, through chi2 test. A total of 15 (26.78%) patients of 56 with ES had autoimmune thyroid disease (subclinical or clinical hypothyroidism). Primary hypothyroidism with negative antithyroid autoantibodies was found in a further 13 patients (23.21%). The 46.42% of ES had primary hypothyroidism; this result had obtained a statistically significant difference when compared to the ratio obtained in the group of diabetes mellitus type 2 (P < 0.0029). There is an important association between ES and autoimmune thyroid disease, which reached 26.78% in our series. We suggest the possibility of a common pathogenesis for certain cases of ES and autoimmune thyroid disease, with the end point of ES in the pituitary, and atrophy in the thyroid gland.

[Pituitary tumorigenesis]

Pituitary adenomas, almost invariably adenomas, account for 10% to 15% of all intracranial neoplasms and are incidentally detected in up to 27% of non selected autopsies. They are morphologically classified as microadenomas (diameter < 1 cm) or macroadenomas, which can be enclosed, invasive and/or expansive. Functionally, they are classified as secreting adenomas (PRL, GH, ACTH, TSH, LH, and FSH, and those co-secreting two or more hormones), and clinically non secreting or "non functioning" tumors. Diagnosis is based on the hypersecretion phenotype (acromegaly, Cushing, etc), and on mass effect of macroadenomas leading to neurological disturbances, mainly visual complaints and headache. Pituitary tumorigenesis mechanisms include those of primary hypothalamic versus pituitary origin, the latter is supported by evidence of pituitary adenoma monoclonality, as well as the absence of hyperplastic tissue surrounding the surgically removed tumor, and the relative independence of tumor hypothalamic control. Nevertheless, a permissive role of the hypothalamus on tumor progression is also postulated. Several molecular mechanisms involved in pituitary tumorigenesis have been unraveled including oncogenes, tumor suppressor genes and growth factors involved in neoplastic development, and will be described in this review.