Pituitary gigantism

Extraordinary case presentations in pediatric pituitary adenoma: report of 6 cases

Pediatric pituitary adenomas (PPAs) are rare neoplasms with a propensity for unusual presentations and an aggressive clinical course. Here, the authors describe 6 highly atypical PPAs to highlight this tendency and discuss unexpected management challenges.A 14-year-old girl presented with acute hemiparesis and aphasia. MRI revealed a pituitary macroadenoma causing internal carotid artery invasion/obliteration without acute apoplexy, which was treated via emergent transsphenoidal resection (TSR). Another 14-year-old girl developed precocious galactorrhea due to macroprolactinoma, which was medically managed. Several years later, she re-presented with acute, severe, bitemporal hemianopia during her third trimester of pregnancy, requiring emergent induction of labor followed by TSR. A 13-year-old boy was incidentally diagnosed with a prolactinoma after routine orthodontic radiographs captured a subtly abnormal sella. An 18-year-old male self-diagnosed pituitary gigantism through a school report on pituitary disease. A 17-year-old boy was diagnosed with Cushing disease by his basketball coach, a former endocrinologist. A 12-year-old girl with growth arrest and weight gain was diagnosed with Cushing disease, which was initially treated via TSR but subsequently recurred and ultimately required 12 operations, 5 radiation treatments involving 3 modalities, bilateral adrenalectomy, and chemotherapy. Despite these efforts, she ultimately died from pituitary carcinoma.

Pituitary gigantism: a retrospective case series

BACKGROUND

Pituitary gigantism (PG) is a rare pediatric disease with poorly defined long-term outcomes. Our aim is to describe the longitudinal clinical course in PG patients using a single-center, retrospective cohort study.

METHODS

Patients younger than 19 years diagnosed with PG were identified. Thirteen cases were confirmed based on histopathology of a GH secreting adenoma or hyperplasia and a height >2 SD for age and gender. Laboratory studies, initial pathology, and imaging were abstracted.

RESULTS

Average age at diagnosis was 13 years with an average initial tumor size of 7.4×3.8 mm. Initial transsphenoidal surgery was curative in 3/12 patients. Four of the nine patients who failed the initial surgery required a repeat procedure. Octreotide successfully normalized GH levels in 1/6 patients with disease refractory to surgery (1/6). Two out of five patients received pegvisomant after failing octreotide but only one patient responded to treatment. Five patients were ultimately treated with radiosurgery or radiation patients were followed for an average of 10 years.

CONCLUSIONS

PG is difficult to treat. In most patients, the initial transsphenoidal surgery failed to normalize GH levels. If the initial surgery was unsuccessful, repeat surgery was unlikely to control GH secretion. Treatment with octreotide or pegvisomant was successful in less than half the patients failing surgery. Radiosurgery was curative, but is not an optimal treatment for pediatric patients. Despite the small sample, our study suggests that the treatment outcome of pediatric PG may be different than adults.

Clinical applications of somatostatin analogs for growth hormone-secreting pituitary adenomas

Excessive growth hormone (GH) is usually secreted by GH-secreting pituitary adenomas and causes gigantism in juveniles or acromegaly in adults. The clinical complications involving cardiovascular, respiratory, and metabolic systems lead to elevated morbidity in acromegaly. Control of serum GH and insulin-like growth factor (IGF) 1 hypersecretion by surgery or pharmacotherapy can decrease morbidity. Current pharmacotherapy includes somatostatin analogs (SAs) and GH receptor antagonist; the former consists of lanreotide Autogel (ATG) and octreotide long-acting release (LAR), and the latter refers to pegvisomant. As primary medical therapy, lanreotide ATG and octreotide LAR can be supplied in a long-lasting formulation to achieve biochemical control of GH and IGF-1 by subcutaneous injection every 4-6 weeks. Lanreotide ATG and octreotide LAR provide an effective medical treatment, whether as a primary or secondary therapy, for the treatment of GH-secreting pituitary adenoma; however, to maximize benefits with the least cost, several points should be emphasized before the application of SAs. A comprehensive assessment, especially of the observation of clinical predictors and preselection of SA treatment, should be completed in advance. A treatment process lasting at least 3 months should be implemented to achieve a long-term stable blood concentration. More satisfactory surgical outcomes for noninvasive macroadenomas treated with presurgical SA may be achieved, although controversy of such adjuvant therapy exists. Combination of SA and pegvisomant or cabergoline shows advantages in some specific cases. Thus, an individual treatment program should be established for each patient under a full evaluation of the risks and benefits.

Overgrowth

The predominant influences on fetal growth are maternal and placental factors. Post-natal growth is regulated by a complex interaction between genetic, environmental and hormonal influences. The role of the growth hormone insulin-like growth factor (GH-IGF) system is explored, including the emerging role of IGF-2 in fetal growth. Increasing understanding of the genetics of overgrowth and short stature syndromes is contributing greatly to basic understanding of growth regulation. A range of prenatal overgrowth syndromes is discussed, including those associated with neonatal hyperinsulinism and hypoglycaemia.Post-natal overgrowth may be caused by a diverse range of normal variant conditions, endocrine disorders, chromosomal abnormalities and other genetic syndromes. An approach to diagnosis is presented and major conditions discussed in detail. Sex-steroid therapy for height limitation continues to be a controversial area with uncertainty about height prediction, benefits achieved and possible long-term side-effects.

Long-acting peptidomimergic control of gigantism caused by pituitary acidophilic stem cell adenoma

Gigantism is caused by GH hypersecretion occurring before epiphyseal long bone closure and usually is associated with pituitary adenoma. A 15-yr-old female patient presented with accelerated growth due to a large pituitary tumor that was surgically resected to relieve pressure effects. Second surgery to remove residual tumor tissue was followed by administration of octreotide LAR, a long-acting depot somatostatin analog, together with long-acting cabergoline. Height was over the 95th percentile, with evidence of a recent growth spurt. Serum GH levels were more than 60 ng/mL (normal, <10 ng/mL) with no suppression to 75 g oral glucose, and serum PRL (>8,000 ng/mL; normal, <23 ng/mL) and insulin-like growth factor I levels (845 ng/mL; age-matched normal, 242-660 ng/mL) were elevated. Histology, immunostaining, and electron microscopy demonstrated a pituitary acidophil stem cell adenoma. Tumor tissue expressed both somatostatin receptor type 2 and dopamine receptor type 2. The Gs alpha subunit, GHRH receptor, and MEN1 genes were intact, and tumor tissue abundantly expressed pituitary tumor transforming gene (PTTG). Serum GH and PRL levels were controlled after two surgeries, and with continued cabergoline and octreotide LAR GH, PRL, and insulin-like growth factor I levels were normalized. In conclusion, administration of long-acting somatostatin analog every 4 weeks in combination with a long-acting dopamine agonist biweekly controlled biochemical parameters and accelerated growth in a patient with gigantism caused by a rare pituitary acidophil stem cell adenoma.

Transsphenoidal surgery for pituitary gigantism and galactorrhea in a 3.5 year old child

The management of pituitary macroadenomas which lead to gigantism may require multiple therapeutical approaches, including medical treatment, surgery, and radiation therapy. Transsphenoidal surgery (TSS) during early childhood that achieves total removal of a growth hormone (GH) secreting tumor is rarely reported. The surgeon is confronted with special problems regarding the infantile anatomy. In this case, a 3.5 year old child, the youngest successfully treated by TSS so far, suffered from a GH- and prolactin (PRL) secreting macroadenoma of the pituitary gland. The girl initially presented with an increasing growth rate, later with breast development, and finally, at the age of 2.8 years, with galactorrhea and secretion of blood from the nipples. Increased levels of GH [122 micrograms/l], insulin-like growth factor (IGF-1) [830 micrograms/l], insulin-like growth factor binding protein 3 (IGFBP-3) [8.6 mg/l] and PRL [590 micrograms/l] were found. MRI scans revealed a macroadenoma of 2.7 cm diameter. An eight-week trial of relatively low dose dopamine agonists led to a reduction of PRL, while the GH- and IGF-1 levels remained unchanged; the tumor showed only little shrinkage. Since there was chiasma compression, we opted for early TSS. A complete tumor removal was achieved despite the difficulties of a narrow approach. After TSS, low levels of GH, IGF-1, and PRL documented a complete tumor removal, but persistent diabetes insipidus and anterior lobe deficits resulted from surgery. In summary, if primary medical therapy alone is unable to adequately reduce hormone hypersecretion and tumor size in early childhood, TSS is recommended. Thus, radiation therapy may be reserved for surgical failure.

Growth hormone-secreting pituitary adenomas in childhood and adolescence: features and results of transnasal surgery

OBJECTIVE

Pituitary tumors causing gigantism are rare in childhood and adolescence. In a review of 2367 patients with pituitary adenomas who were treated between 1970 and 1997, we found 15 cases (0.63%, 9 male and 6 female patients) of growth hormone-secreting pituitary adenomas in patients who were less than 20 years of age at the time of surgery, and we compared their characteristics with those of adenomas in an adult group.

METHODS

Patients were grouped according to their ages at the first operation, with five patients (33.3%) in the prepubescent group (0-11 yr), eight (53.3%) in the pubescent group (12-17 yr), and two (13.3%) in the postpubescent group (18-19 yr). All 15 patients exhibited the typical symptoms of growth hormone oversecretion. The incidence of hyperprolactinemia among patients with prepubescent onset was 66.7%. Radiological examinations demonstrated microadenomas in 4 patients (26.7%) and macroadenomas in 11 patients (73.3%). The mean follow-up period was 73.5 months.

RESULTS

Direct transnasal explorations were performed for all patients. Tumor invasion into the cavernous sinus was observed in six patients (40%). Radical tumor resection was performed for four patients (80%) in the prepubescent group, for five patients (62.5%) in the pubescent group, and for neither patient in the postpubescent group. Surgical morbidity was caused by permanent diabetes insipidus in three patients (20%). Rapid growth was postoperatively improved in 80% of the prepubescent age group. The recurrence rate was 13.3% (2 of 15 patients).

CONCLUSION

Transnasal pituitary surgery was found to be as safe in pediatric patients with gigantism as in adults. Growth hormone-secreting pituitary adenomas in childhood and adolescence were more likely to be invasive or aggressive than were those in adulthood. The clinical biological characteristics for children were different from those for adults.