Diagnosis and Management of Pituitary Adenomas: A Review.

Importance: Pituitary adenomas are neoplasms of the pituitary adenohypophyseal cell lineage and include functioning tumors, characterized by the secretion of pituitary hormones, and nonfunctioning tumors. Clinically evident pituitary adenomas occur in approximately 1 in 1100 persons. Observations: Pituitary adenomas are classified as either macroadenomas (≥10 mm) (48% of tumors) or microadenomas (<10 mm). Macroadenomas may cause mass effect, such as visual field defects, headache, and/or hypopituitarism, which occur in about 18% to 78%, 17% to 75%, and 34% to 89% of patients, respectively. Thirty percent of pituitary adenomas are nonfunctioning adenomas, which do not produce hormones. Functioning tumors are those that produce an excess of normally produced hormones and include prolactinomas, somatotropinomas, corticotropinomas, and thyrotropinomas, which produce prolactin, growth hormone, corticotropin, and thyrotropin, respectively. Approximately 53% of pituitary adenomas are prolactinomas, which can cause hypogonadism, infertility, and/or galactorrhea. Twelve percent are somatotropinomas, which cause acromegaly in adults and gigantism in children, and 4% are corticotropinomas, which secrete corticotropin autonomously, resulting in hypercortisolemia and Cushing disease. All patients with pituitary tumors require endocrine evaluation for hormone hypersecretion. Patients with macroadenomas additionally require evaluation for hypopituitarism, and patients with tumors compressing the optic chiasm should be referred to an ophthalmologist for formal visual field testing. For those requiring treatment, first-line therapy is usually transsphenoidal pituitary surgery, except for prolactinomas, for which medical therapy, either bromocriptine or cabergoline, is usually first line. Conclusions and Relevance: Clinically manifest pituitary adenomas affect approximately 1 in 1100 people and can be complicated by syndromes of hormone excess as well as visual field defects and hypopituitarism from mass effect in larger tumors. First-line therapy for prolactinomas consists of bromocriptine or cabergoline, and transsphenoidal pituitary surgery is first-line therapy for other pituitary adenomas requiring treatment.

Italian Association of Clinical Endocrinologists (AME) and International Chapter of Clinical Endocrinology (ICCE). Position statement for clinical practice: prolactin-secreting tumors.

Prolactinomas are the most frequent pituitary adenomas. Prolactinoma may occur in different clinical settings and always require an individually tailored approach. This is the reason why a panel of Italian neuroendocrine experts was charged with the task to provide indications for the diagnostic and therapeutic approaches that can be easily applied in different contexts. The document provides 15 recommendations for diagnosis and 54 recommendations for treatment, issued according to the GRADE system. The level of agreement among panel members was formally evaluated by RAND-UCLA methodology. In the last century, prolactinomas represented the paradigm of pituitary tumors for which the development of highly effective drugs obtained the best results, allowing to avoid neurosurgery in most cases. The impressive improvement of neurosurgical endoscopic techniques allows a far better definition of the tumoral tissue during surgery and the remission of endocrine symptoms in many patients with pituitary tumors. Consequently, this refinement of neurosurgery is changing the therapeutic strategy in prolactinomas, allowing the definitive cure of some patients with permanent discontinuation of medical therapy.

Outcomes of surgical and/or medical treatment in patients with prolactinomas during long-term follow-up: a retrospective single-centre study.

OBJECTIVES: Prolactinoma is the most common cause of pituitary tumours. Current medical guidelines recommend dopamine agonists (cabergoline or bromocriptine) as the initial therapy for prolactinoma. However, surgical removal can also be considered in selected cases, such as patients with macroadenomas with local complications (bleeding or optic chiasm pressure) or those not responding to medical treatment. METHODS: The present retrospective study included patients with prolactinomas (n=43; female, 24; male, 19) who were primarily managed with medical (n=32) or surgical (n=11) treatment. RESULTS: Macroadenoma (n=29.67%) was commonly detected in both genders (female, 54%; male, 84%). Moreover, the mean pre-treatment prolactin levels were similar in both genders (female, 683.3 ± 1347 ng/mL; male, 685.4 ± 805 ng/mL; p=0.226). Surgically treated patients had a greater reduction in tumour size (27.7 ± 17.9 mm pre-treatment vs. 8.72 ± 14.2 mm post-treatment) than non-surgically treated ones (12.5 ± 7.5 mm pre-treatment vs. 4.1 ± 4.2 mm post-treatment; p=0.00). However, the decrease in prolactin levels was similar between the two patient groups (p=0.108). During the follow-up period (10.6 ± 7.0 years), the average cabergoline dose of the patients was 1.42 ± 1.47 mcg/week. CONCLUSIONS: Although a surgical approach was considered for selected cases of prolactinoma, the average dose used for medical treatment was highly inadequate for the patients in the present study.

Pituitary Adenomas in Transgender Individuals?

Transgender individuals may receive long-term hormonal treatment as part of their sexual transition; limited literature has suggested that they consequently may be predisposed to development of prolactinomas. We questioned whether we had encountered such cases. Pathology databases were searched for the years 2000-2019 for tissue specimens from transgender individuals; Sixty surgical specimens from 58 individuals and 8 cytology specimens were identified. Two of these 60 were pituitary adenomas, neither of which were lactotroph adenomas (prolactinomas).The first occurred in a 71-year-old transgender male-to-female who had undergone high-dose hormone therapy, followed by orchiectomy 30 years prior. Chronic hypertension, dizziness, and vertigo prompted an endocrine workup which revealed elevated IGF-1 and prolactin; The pituitary mass proved to be a mixed somatotroph/lactotroph adenoma. The second occurred in a 53-year-old transgender male-to-female who was being evaluated by an endocrinologist prior to initiating hormone therapy for transition when a slightly elevated prolactin level was discovered. This pituitary macroadenoma proved to be a gonadotroph adenoma. The most common surgical specimens were 33 bilateral mastectomies, 13 hysterectomies, and 4 orchiectomies, almost all for gender transition purposes rather than medical conditions. Pathologists may wish to be aware of the occurrence of pituitary adenomas in transgender individuals, although the incidence is quite low.

mPRs represent a novel target for PRL inhibition in experimental prolactinomas.

Membrane progesterone receptors are known to mediate rapid nongenomic progesterone effects in different cell types. Recent evidence revealed that mPRα is highly expressed in the rat pituitary, being primarily localized in lactotrophs, acting as an intermediary of P4-inhibitory actions on prolactin secretion. The role of mPRs in prolactinoma development remains unclear. We hypothesize that mPR agonists represent a novel tool for hyperprolactinemia treatment. To this end, pituitary expression of mPRs was studied in three animal models of prolactinoma. Expression of mPRs and nuclear receptor was significantly decreased in tumoral pituitaries compared to normal ones. However, the relative proportion of mPRα and mPRß was highly increased in prolactinomas. Interestingly, the selective mPR agonist (Org OD 02-0) significantly inhibited PRL release in both normal and tumoral pituitary explants, displaying a more pronounced effect in tumoral tissues. As P4 also regulates PRL secretion indirectly, by acting on dopaminergic neurons, we studied mPR involvement in this effect. We found that the hypothalamus has a high expression of mPRs. Interestingly, both P4 and OrgOD 02-0 increased dopamine release in hypothalamus explants. Moreover, in an in vivo treatment, that allows both, pituitary and hypothalamus actions, the mPR agonist strongly reduced the hyperprolactinemia in transgenic females carrying prolactinoma. Finally, we also found and interesting gender difference: males express higher levels of pituitary mPRα/ß, a sex that does not develop prolactinoma in these mice models. Taken together, these findings suggest mPRs activation could represent a novel tool for hyperprolactinemic patients, especially those that present resistance to dopaminergic drugs.

Association of prolactin receptor (PRLR) variants with prolactinomas.

Prolactinomas are the most frequent type of pituitary tumors, which represent 10-20% of all intracranial neoplasms in humans. Prolactinomas develop in mice lacking the prolactin receptor (PRLR), which is a member of the cytokine receptor superfamily that signals via Janus kinase-2-signal transducer and activator of transcription-5 (JAK2-STAT5) or phosphoinositide 3-kinase-Akt (PI3K-Akt) pathways to mediate changes in transcription, differentiation and proliferation. To elucidate the role of the PRLR gene in human prolactinomas, we determined the PRLR sequence in 50 DNA samples (35 leucocytes, 15 tumors) from 46 prolactinoma patients (59% males, 41% females). This identified six germline PRLR variants, which comprised four rare variants (Gly57Ser, Glu376Gln, Arg453Trp and Asn492Ile) and two low-frequency variants (Ile76Val, Ile146Leu), but no somatic variants. The rare variants, Glu376Gln and Asn492Ile, which were in complete linkage disequilibrium, and are located in the PRLR intracellular domain, occurred with significantly higher frequencies (P < 0.0001) in prolactinoma patients than in 60 706 individuals of the Exome Aggregation Consortium cohort and 7045 individuals of the Oxford Biobank. In vitro analysis of the PRLR variants demonstrated that the Asn492Ile variant, but not Glu376Gln, when compared to wild-type (WT) PRLR, increased prolactin-induced pAkt signaling (>1.3-fold, P < 0.02) and proliferation (1.4-fold, P < 0.02), but did not affect pSTAT5 signaling. Treatment of cells with an Akt1/2 inhibitor or everolimus, which acts on the Akt pathway, reduced Asn492Ile signaling and proliferation to WT levels. Thus, our results identify an association between a gain-of-function PRLR variant and prolactinomas and reveal a new etiology and potential therapeutic approach for these neoplasms.

Nonalcoholic fatty liver disease with prolactin-secreting pituitary adenoma in an adolescent: A case report.

RATIONALE: Nonalcoholic fatty liver disease (NAFLD), among the commonest chronic liver disorders in children and adolescents, is considered a reflection of the current obesity epidemic in children and adults. This liver disease has been linked with various metabolic disorders, but not with prolactinoma (PRLoma). PATIENT CONCERNS: A 13-year-old Japanese girl manifested obesity, serum transaminase and γ-glutamyltransferase elevations, and amenorrhea. Abdominal ultrasonography showed fatty liver. Her serum prolactin concentration was elevated, and cranial magnetic resonance imaging showed a pituitary mass consistent with macroadenoma. DIAGNOSES: NAFLD and PRLoma. INTERVENTIONS AND OUTCOMES: After the patient's NAFLD failed to respond to diet and exercise, cabergoline treatment of the PRLoma decreased body weight, serum transaminase and γ-glutamyltransferase elevations, and ultrasonographic fatty liver grade as the tumor became smaller. LESSONS: Physicians should consider the possibility of PRLoma when diet and exercise fail to improve fatty liver disease in a patient with endocrine symptoms such as amenorrhea.

Prenatal alcohol exposure increases the susceptibility to develop aggressive prolactinomas in the pituitary gland.

Excess alcohol use is known to promote development of aggressive tumors in various tissues in human patients, but the cause of alcohol promotion of tumor aggressiveness is not clearly understood. We used an animals model of fetal alcohol exposure that is known to promote tumor development and determined if alcohol programs the pituitary to acquire aggressive prolactin-secreting tumors. Our results show that pituitaries of fetal alcohol-exposed rats produced increased levels of intra-pituitary aromatase protein and plasma estrogen, enhanced pituitary tissue growth, and upon estrogen challenge developed prolactin-secreting tumors (prolactinomas) that were hemorrhagic and often penetrated into the surrounding tissue. Pituitary tumors of fetal alcohol-exposed rats produced higher levels of hemorrhage-associated genes and proteins and multipotency genes and proteins. Cells of pituitary tumor of fetal alcohol exposed rat grew into tumor spheres in ultra-low attachment plate, expressed multipotency genes, formed an increased number of colonies, showed enhanced cell migration, and induced solid tumors following inoculation in immunodeficient mice. These data suggest that fetal alcohol exposure programs the pituitary to develop aggressive prolactinoma after estrogen treatment possibly due to increase in stem cell niche within the tumor microenvironment.

Polimorfismos del receptor D2 / D2 receptor polymorphisms

Los prolactinomas son tumores bien diferenciados que se originan en las células lactotropas pituitarias, una línea celular que secreta fisiológicamente prolactina (PRL). A nivel hipofisario, la dopamina está implicada en la regulación de la secreción de PRL por las células lactotropas y este efecto inhibitorio está mediado por la activación del receptor de prolactina tipo 2 (DRD2). Hay varios polimorfismos del DRD2, el primero y más estudiado es TaqI A1; está demostrado que este alelo se encuentra asociado a una reducción de la actividad cerebral dopaminérgica, además de observarse una reducción en su capacidad de unión de aproximadamente un 30%. Este alelo se ha vinculado con una menor densidad de DRD2 en el cuerpo estriado, especialmente en el putamen y caudado ventral, y la cantidad de DRD2 en portadores del alelo A1 fue un 30-40% más bajo que en los no portadores (es decir, TaqI A2 homocigotos). En la literatura, hay evidencia que apoya la posible participación de los polimorfismos DRD2 en la regulación de la secreción hormonal.

Prolactinomas are well differentiated tumours that originate in the pituitary lactotrope cells, a cell line that physiologically secretes prolactin (PRL). At pituitary level, dopamine is involved in the regulation of PRL secretion by lactotropes, and this inhibitory effect is mediated by activation of prolactin type 2 receptor (DRD2). Of the several DRD2 polymorphisms, the first and most studied is TaqI A1. It has been demonstrated that this allele is associated with a reduced dopaminergic brain activity, and a reduction in its binding capacity of approximately 30% also being observed. This allele was associated with a lower density of DRD2 in the striatum, especially in the putamen and ventral caudate. The amount of DRD2 in A1 allele carriers was 30 - 40% lower than in non-carriers (this is, TaqI A2 Homozygotes). There is evidence in the literature, that supports the possible involvement of DRD2 polymorphisms in the regulation of hormonal secretion.

[Multiple Endocrine Neoplasia I (Wermers Syndrome), Forms of Clinical Manifestation, 5 Case Studies]. / Mnohocetná endokrinní neoplazie I (Wermeruv syndrom) - formy klinické manifestace: 5 kazuistik.

Multiple Endocrine Neoplasia (MEN) is a condition in which several endocrine organs of an individual are affected by adenoma, hyperplasia and less often carcinoma, either simultaneously or at different stages of life. Two existing syndromes, MEN1 and MEN2 (2A, 2B), in literature is also mentioned MEN4, are associated also with other non-endocrine disorders. MEN1 (Wermer syndrome) affects the pituitary, parathyroid, and pancreatic area. 95 % of patients show very early manifestation of hyperparathyroidism, often before 40 years of age. Multiple adenomas gradually involve all four parathyroid glands. The first clinical sign of MEN1 includes recurrent nephrolithiasis. The second most frequent manifestation of MEN1 is pancreatic area (pancreas, stomach and duodenum), again multiple malignancies of varying degree which can metastasize. Most often gastrinomas and insulinomas are involved. Pituitary adenomas occur in about one third of MEN1 patients and tend to be larger and less responsive to treatment. Tumors appearing most often are prolactinomas, tumors producing growth hormone, or afunctional adenomas. The other endocrine tumors include carcinoids and adrenal lesions. In the last year we have registered four MEN1 syndrome patients in our center and one patient has been already followed since 2008. In four out of five patients, nephrolithiasis after 30 years of age was the first clinical symptom, but only one of theses cases resulted in MEN1 diagnosis. In all patients, the clinical symptoms intensified and the diagnosis was established between 36 and 40 years of age. A crutial factor is a cooperation with the urology examination of kidney stones formation in young individuals with nephrolithiasis in order to reveal the potential cases of MEN1 syndrome very early on. Consider the MEN1 genetic diagnostics if recurrent primary hyperparathyroidism or recurrent gastroduodenal ulcer disease appear in patients under 40 years of age.Key words: carcinoid - gastrinoma - hyperparathyroidism - insulinoma - MEN1 - multiple endocrine neoplasia - nefrolithiasis - neuroendocrine tumor - pancreatic area - pituitary gland.

Pituitary Prolactinoma Imaged by 99mTc-Sestamibi SPECT/CT in a Multiple Endocrine Neoplasia Type 1 Patient.

A 35-year-old woman who had undergone bilateral inferior parathyroidectomy for primary hyperparathyroidism was referred to our hospital to evaluate the cause of irregular menses, galactorrhea, and paroxysmal headache. Multiple endocrine neoplasia type 1 was then suspected for the high levels of plasma prolactin, parathyroid hormone, serum calcium, insulin, and related symptoms. A Tc-sestamibi SPECT/CT acquired to evaluate parathyroid glands unexpectedly revealed an increased accumulation in the pituitary gland, which was further confirmed by enhanced magnetic resonance imaging as a pituitary microadenoma. Bromocriptine treatment gradually reduced the prolactin level.

Prolactin-producing pituitary adenoma with atypical spindle cell morphology: a case report.

Reported herein is a 25-year-old woman who was treated for a large and highly atypical prolactin-producing pituitary adenoma. On presentation, she exhibited right hemiparesis and left-sided visual loss, associated with amenorrhea. A massive (>5 cm) intra- and suprasellar lesion was seen on imaging, and her serum prolactin level was 4408 ng/ml. The patient received dopamine agonist treatment preoperatively for 4 weeks. To resect the tumor, a two-stage excision was required. Histologically, the specimen was composed of polygonal or spindle cells showing marked nuclear pleomorphism and/or multinucleation. Fibrosis was also focally conspicuous. Differential diagnoses included pituitary adenoma, pituitary carcinoma, pituicytoma, paraganglioma, spindle cell oncocytoma, and meningioma. Immunohistochemically, the tumor cells were positive for prolactin, chromogranin-A, and synaptophysin, but were negative for glial fibrillary acidic protein, S-100 protein, epithelial membrane antigen, and vimentin. No apparent cerebrospinal or systemic metastases are found. Ultimately, prolactin-producing pituitary adenoma was diagnosed. Our case highlights the difficulty in definitively diagnosing an unusual prolactin-producing adenoma based on histopathology alone and the importance of referring to clinical information and immunohistochemical findings when deriving the diagnosis.

Radiation-induced ocular motor cranial nerve palsies in patients with pituitary tumor.

BACKGROUND: Radiation therapy is often used in the treatment of pituitary tumor. Diplopia due to radiation damage to the ocular motor cranial nerves has been infrequently reported as a complication in this clinical setting. METHODS: Retrospective case series of 6 patients (3 men and 3 women) with pituitary adenoma, all of whom developed diplopia following transsphenoidal resection of pituitary adenoma with subsequent radiation therapy. None had evidence of tumor involvement of the cavernous sinus. RESULTS: Five patients developed sixth nerve palsies, 3 unilateral and 2 bilateral, and in 1 patient, a sixth nerve palsy was preceded by a fourth cranial nerve palsy. One patient developed third nerve palsy. Five of the 6 patients had a growth hormone-secreting pituitary tumor with acromegaly. Following transsphenoidal surgery in all 6 patients (2 had 2 surgeries), 4 had 2 radiation treatments consisting of either radiosurgery (2 patients) or external beam radiation followed by radiosurgery (2 patients). CONCLUSIONS: Patients with pituitary tumors treated multiple times with various forms of radiation therapy are at risk to sustain ocular motor cranial nerve injury. The prevalence of acromegalic patients in this study reflects an aggressive attempt to salvage patients with recalcitrant growth hormone elevation and may place the patient at a greater risk for ocular motor cranial nerve damage.

Pituitary adenomas in childhood, adolescence and young adulthood: presentation, management, endocrine and metabolic outcomes.

OBJECTIVE: To elucidate the long-term outcomes of pituitary adenomas diagnosed in childhood and adolescence, knowledge of which remains sparse. DESIGN AND METHODS: A retrospective review of patients aged ≤21 years at diagnosis of pituitary adenoma, attending a neuroendocrine service in Liverpool, UK, between 1984-2009. RESULTS: There were 41 patients (33 female), mean age at diagnosis 17.3 years (range 11-21) and mean follow-up 9.6 years; 29 patients had prolactinomas (15 macroprolactinomas), 6 non-functioning pituitary adenomas (NFPAs), 5 Cushing's disease (CD) and 1 acromegaly. All prolactinoma patients received dopamine agonists (DAs) and three also underwent pituitary surgery. Furthermore, ten patients underwent surgery: five with CD, one with acromegaly and four with NFPA. Four received radiotherapy after surgery. Another ten patients received hormone replacement: nine hydrocortisone, five thyroxine, seven sex steroids and five GH; another seven had severe asymptomatic GH deficiency. Three female patients were treated for infertility (two successfully). Thirteen patients gained significant weight (body mass index (BMI) increase >2 kg/m(2)) since diagnosis and 16 in total are now obese (BMI>30 kg/m(2)). Five were treated with orlistat and one attended a weight management service. Two received antihypertensive medications, two had type 2 diabetes and four were treated for dyslipidaemia. CONCLUSIONS: This is one of the largest reviews of patients aged 21 or younger at diagnosis of pituitary adenoma followed up by a single service. Two-thirds had prolactinomas, all were treated with DAs and three underwent surgery. Increased cardiovascular risk factors (obesity and dyslipidaemia) and infertility are important sequelae and active identification and treatment are necessary.

Enhanced LH action in transgenic female mice expressing hCGbeta-subunit induces pituitary prolactinomas; the role of high progesterone levels.

The etiology of pituitary adenomas remains largely unknown, with the exception of involvement of estrogens in the formation of prolactinomas. We have examined the molecular pathogenesis of prolactin-producing pituitary adenomas in transgenic female mice expressing the human choriongonadotropin (hCG) beta-subunit. The LH/CG bioactivity is elevated in the mice, with consequent highly stimulated ovarian progesterone (P(4)) production, in the face of normal estrogen secretion. Curiously, despite normal estrogen levels, large prolactinomas developed in these mice, and we provide here several lines of evidence that the elevated P(4) levels are involved in the growth of these estrogen-dependent tumors. The antiprogestin mifepristone inhibited tumor growth, and combined postgonadectomy estradiol/P(4) treatment was more effective than estrogen alone in inducing tumor growth. Evidence for direct growth-promoting effect of P(4) was obtained from cultures of primary mouse pituitary cells and rat somatomammotroph GH3 cells. The mouse tumors and cultured cells revealed stimulation of the cyclin D1/cyclin-dependent kinase 4/retinoblastoma protein/transcription factor E2F1 pathway in the growth response to P(4). If extrapolated to humans, and given the importance of endogenous P(4) and synthetic progestins in female reproductive functions and their pharmacotherapy, it is relevant to revisit the potential role of these hormones in the origin and growth of prolactinomas.

Pituitary tumours: the prolactinoma.

This review focus on the epidemiology, diagnosis and treatment of prolactinomas. In particular, attention was given to recent data showing a high prevalence of these tumours in the general population, 3-5 times higher than previously reported. The diagnosis of hyperprolactinaemia has been simplified in recent years, and only prolactin (PRL) assay and magnetic resonance imaging of the sella are required. Nonetheless, macroprolactinaemia should be assessed in patients with hyperprolactinaemia in the absence of clinical symptoms of elevated PRL levels. The recent evidence that medical therapy with dopamine agonists should be continued lifelong has been confirmed by several studied. The patients achieving disappearance of the tumours and suppression of PRL levels during treatment are those showing the highest likelihood to have persistent remission of hyperprolactinaemia after treatment withdrawal.

Simultaneous above and below approach to giant pituitary adenomas: surgical strategies and long-term follow-up.

INTRODUCTION: Giant pituitary adenomas of excessive size, fibrous consistency or unfavorable geometric configuration may be unresectable through conventional operative approaches. We present our select case series for operative resection and long-term follow-up for these unusual tumors, employing both a staged procedure and a combined transsphenoidal-transcranial above and below approach. METHOD: A retrospective chart review was performed on patients operated via the staged, and combined approaches by the senior author (J.N.B.). Preoperative characteristics and postoperative outcomes were reviewed. A detailed description of the operative technique and perioperative management is provided. RESULTS: Between 1993 and 1996, two patients harboring giant pituitary adenomas underwent an intentionally staged resection, and between 1997 and 2006, nine patients harboring giant pituitary adenomas underwent surgery via a single-stage above and below approach. Nine patients (82%) presented with non-secreting adenomas and two patients (18%) presented with prolactinomas refractory to medical management. Gross total resection was achieved in six patients (55%), near total resection in 1 (9%), and subtotal removal in 4 (36%). Seven patients (64%) experienced visual improvement postoperatively and no major complications occurred. Long-term follow-up averaged 51.6 months. Panhypopituitarism was observed in four patients, partial hypopituitarism in four, persistent DI in two, and persistent SIADH in one. CONCLUSIONS: The addition of a transcranial component to the transsphenoidal approach offers additional visualization of critical neurovascular structures during giant pituitary adenoma resection. Complications rates are similar to other series in which complex pituitary adenomas are resected by other means. The above and below approach is both safe and effective and the immediate and long-term advantages of a single-stage approach justify its utility in this select group of patients.

Can radiation induce pituitary tumors? Giant prolactinoma after radiation exposure.

Radiation is a well-known etiology for many CNS tumors, including meningiomas, sarcomas and gliomas. However, occurrence of pituitary adenoma after radiation exposure is rare. We report a 21-year-old man with a pituitary adenoma, who was treated with post-operative radiotherapy for pontine glioma at 6 years of age. The role of radiation exposure in the etiology of pituitary adenoma is discussed, along with a literature review of radiation-induced tumors.