A case of pituitary somatotroph adenoma with concomitant secretion of growth hormone, prolactin, and adrenocorticotropic hormone--an adenoma derived from primordial stem cell, studied by immunohistochemistry, in situ hybridization, and cell culture

Pathogenesis, clinical features, and treatment of plurihormonal pituitary adenoma

Plurihormonal pituitary adenoma (PPA) is a type of pituitary tumor capable of producing two or more hormones and usually presents as an aggressive, large adenoma. As yet, its pathogenesis remains unclear. This is the first study to systematically summarize the underlying pathogenesis of PPA. The pathogenesis is related to plurihormonal primordial stem cells, co-transcription factors, hormone co-expression, differential gene expression, and cell transdifferentiation. We conducted a literature review of PPA and analyzed its clinical characteristics. We found that the average age of patients with PPA was approximately 40 years, and most showed only one clinical symptom. The most common manifestation was acromegaly. Currently, PPA is treated with surgical resection. However, recent studies suggest that immunotherapy may be a potentially effective treatment.

Clinicopathological Characteristics of Plurihormonal Pituitary Adenoma

Background

As the pathogenesis of plurihormonal pituitary adenoma (PPA) is unclear and the diagnostic criteria are inconsistent, clinicians still find it challenging to diagnose. To analyze the relationship between clinical and pathological characteristics in PPA.

Methods

The clinical data of patients with 70 PPAs admitted during 2008-2010 and 2019-2020 were collected and analyzed. In particular, hormone examination using cell culture supernatant was performed to confirm PPA cases from 2019 to 2020.

Results

PPA accounted for 13% of all pituitary cases recorded in the same period. There were 30 men and 40 women. Fifty-three percent of patients had one endocrine manifestation, and 1% presented with two endocrine symptoms. However, none of the patients had three endocrine manifestations. The level of one and two types of hormones was elevated in 52 (74.3%) and 5 (7.1%) patients, respectively and that of three types of hormones was increased only in one patient. Immunohistochemical staining for PRL + TSH or FSH/LH was most commonly performed (n = 17), followed by that for PRL + GH + ACTH and PRL + GH + TSH or FSH/LH (n = 14) and PRL + ACTH (n = 10). The primary culture results in vitro were consistent with the pathological findings in five (41.7%) patients. Moreover, 4 of 12 patients diagnosed with PPA during 2019-2020 tested positive for SOX2.

Conclusion

The pathogenesis of PPA remains elusive due to the lack of specific clinical symptoms and endocrine changes. Examination of hormones on tumor culture supernatant is helpful for its diagnosis.

Plurihormonal pituitary macroadenoma: a case report

Background

Plurihormonal pituitary adenomas are a unique type of pituitary adenomas that secrete two or more pituitary hormones normally associated with separate cell types that have different immunocytochemical and ultrastructural features. Although they represent 10–15% of all pituitary tumors, only a small fraction of plurihormonal pituitary adenomas clinically secrete multiple hormones. The most common hormone combinations secreted by plurihormonal pituitary adenomas are growth hormone, prolactin, and one or more glycoprotein hormones. The most common hormonal symptom is acromegaly (50%). The aim of this case report is to bring awareness about this rare type of pituitary adenomas and to describe the unique presentation of our patient, even though plurihormonal pituitary adenomas are known mostly as a clinically silent tumors.

Case presentation

Herein, we describe an unusual case of plurihormonal pituitary adenoma with triple-positive staining for adrenocorticotropic hormone, growth hormone, and prolactin. The patient is a 65-year-old Egyptian woman who presented with mass effect symptoms of the pituitary tumor, which primarily manifested as severe headache and visual field defects. She also presented with some cushingoid features, and further analysis confirmed Cushing’s disease; slightly high prolactin and normal growth hormone levels were observed. She underwent transsphenoidal surgery and has been in remission thus far. Only a few cases have been reported in the literature, but none has exhibited silent acromegaly or mass effect symptoms as the initial presentation.

Conclusion

This case highlights an unusual plurihormonal pituitary adenoma case with a rare combination of secreted hormones; mass effect symptoms were dominant, as were uncommon visual field defects. Our case further proves that immunohistochemical analyses of all pituitary hormones are needed to ensure correct diagnosis and to alert clinicians to the need for more rigorous follow-up due to the higher morbidity of these patients. Our case report approval number Federal Wide Assurance NIH, USA is FWA00018774 IRB registration number with OHRP/NIH is IRB00010471.

Expression of additional transcription factors is of prognostic value for aggressive behavior of pituitary adenomas

OBJECTIVE

According to the latest WHO classification of tumors of endocrine organs in 2017, plurihormonal adenomas are subclassified by their transcription factor (TF) expression. In the group of plurihormonal adenomas with unusual immunohistochemical combinations (PAWUC), the authors identified a large fraction of adenomas expressing TFs for gonadotroph adenoma (TFGA) cells in addition to other TFs. The aim of this study was to compare clinicopathological parameters of PAWUC with TFGA expression to gonadotroph adenomas that only express TFGA.

METHODS

This retrospective single-center series comprises 73 patients with TFGA-positive pituitary adenomas (SF1, GATA3, estrogen receptor α): 22 PAWUC with TFGA (TFGA-plus group) and 51 with TFGA expression only (TFGA-only group). Patient characteristics, outcome parameters, rate of invasiveness (assessed by direct endoscopic inspection), and MIB1 and MGMT status were compared between groups.

RESULTS

Patients in the TFGA-plus group were significantly younger than patients in the TFGA-only group (age 46 vs 56 years, respectively; p = 0.007). In the TFGA-only group, pituitary adenomas were significantly larger (diameter 25 vs 18.3 mm, p = 0.002). Intraoperatively, signs of invasiveness were significantly more common in the TFGA-plus group than in the TFGA-only group (50% vs 16%, p = 0.002). Gross-total resection was significantly lower in the nonfunctioning TFGA-plus group than in the TFGA-only group (44% vs 86%, p = 0.004). MIB1 and MGMT status showed no significant difference between groups.

CONCLUSIONS

These data suggest a more aggressive behavior of TFGA-positive adenomas if an additional TF is expressed within the tumor cells. Shorter radiographic surveillance and earlier consideration for retreatment should be recommended in these adenoma types.

Plurihormonal Pituitary Tumor of Pit-1 and SF-1 Lineages, with Synchronous Collision Corticotroph Tumor: a Possible Stem Cell Phenomenon

Thyrotropin (TSH)-secreting pituitary tumors are the rarest functioning pituitary tumors. Nonetheless, they are not infrequently plurihormonal, as they may express/secrete hormones made by other pituitary cells derived from the Pit-1 lineage such as growth hormone (GH), prolactin (PRL), and α-subunit (αSU). However, adrenocorticotropin (ACTH) or gonadotropin secretion by such a tumor is exceptional. Although double pituitary tumors are rare, they often combine ACTH and GH secretion. A 41-year-old presented almost 2 years after delivering her 10th child; she had thyrotoxicosis (goiter and palpitations) masquerading as autoimmune postpartum thyroiditis. She was still breastfeeding and amenorrheic. She proved to have TSH, GH, PRL, and ACTH hypersecretion. Imaging revealed an invasive pituitary macrotumor. She had stigmata neither of Cushing's disease nor of acromegaly. Prior to surgery, hormonal control was achieved for close to 1 year by combined octreotide and cabergoline treatment with significant shrinking of the tumor. Following surgery, pathology revealed a collision tumor; the dominant lesion was positive for GH, βTSH, βFSH, and αSU and expressed both Pit-1 and SF-1.The smaller lesion was a corticotroph tumor. We report an unusual plurihormonal tumor co-expressing Pit-1 and SF-1 along with hormones made by cells of both lineages. Its simultaneous occurrence adjacent to a corticotroph tumor raises questions regarding the pathogenesis of these tumors. We propose the possibility of a stem cell tumor with multiple lineage differentiation. We hypothesize that pregnancy might have played a permissive role in tumorigenesis.

Plurihormonal ACTH-GH Pituitary Adenoma: Case Report and Systematic Literature Review

BACKGROUND

Plurihormonal adenomas (PHAs) represent 10%-15% of all functioning pituitary adenomas. The most frequent hormonal associations are with prolactin and growth hormone (GH). Here we describe a rare case of functional adrenocorticotropic hormone (ACTH) and GH microadenoma and report our findings from a systematic literature review of PHA.

METHODS

We searched PubMed using the terms "plurihormonal pituitary adenoma," "ACTH GH pituitary adenoma," and "acromegaly AND Cushing's disease". In the 17 articles that were selected for literature review, only 20% (4/20) of patients presented with clinical signs of both diseases. Histologically, 19 were pituitary adenomas composed of two distinct cell populations, while only in 1 case was there evidence of a single cell producing both ACTH and GH. In the case reported here, a 60-year-old woman was incidentally diagnosed with a pituitary microadenoma. Endocrine assessment documented increased levels of insulin-like growth factor 1 and GH; ACTH and cortisol values were within normal ranges. Echocardiography documented ventricular hypertrophy. Because of clinical and biochemical evidence of acromegaly, surgery was recommended. Postoperatively, hormonal replacement therapy was started because of adrenal insufficiency. Her antihypertensive therapy was discontinued due to evidence of normal blood pressure values. Histological examination revealed an ACTH-GH PHA with 2 distinct populations of secreting cells. At 3-year follow-up, the patient showed stable clinical remission and was no longer receiving hormonal replacement therapy.

CONCLUSIONS

This is an additional case to the 20 previously reported cases of ACTH-GH PHA. Awareness of this relatively rare entity is clinically relevant. The cytogenesis of ACTH-GH PHA remains a matter of debate, and several hypotheses have been postulated.

Somatotropinomas, but not nonfunctioning pituitary adenomas, maintain a functional apoptotic RET/Pit1/ARF/p53 pathway that is blocked by excess GDNF

Acromegaly is caused by somatotroph cell adenomas (somatotropinomas [ACROs]), which secrete GH. Human and rodent somatotroph cells express the RET receptor. In rodents, when normal somatotrophs are deprived of the RET ligand, GDNF (Glial Cell Derived Neurotrophic Factor), RET is processed intracellularly to induce overexpression of Pit1 [Transcription factor (gene : POUF1) essential for transcription of Pituitary hormones GH, PRL and TSHb], which in turn leads to p19Arf/p53-dependent apoptosis. Our purpose was to ascertain whether human ACROs maintain the RET/Pit1/p14ARF/p53/apoptosis pathway, relative to nonfunctioning pituitary adenomas (NFPAs). Apoptosis in the absence and presence of GDNF was studied in primary cultures of 8 ACROs and 3 NFPAs. Parallel protein extracts were analyzed for expression of RET, Pit1, p19Arf, p53, and phospho-Akt. When GDNF deprived, ACRO cells, but not NFPAs, presented marked level of apoptosis that was prevented in the presence of GDNF. Apoptosis was accompanied by RET processing, Pit1 accumulation, and p14ARF and p53 induction. GDNF prevented all these effects via activation of phospho-AKT. Overexpression of human Pit1 (hPit1) directly induced p19Arf/p53 and apoptosis in a pituitary cell line. Using in silico studies, 2 CCAAT/enhancer binding protein alpha (cEBPα) consensus-binding sites were found to be 100% conserved in mouse, rat, and hPit1 promoters. Deletion of 1 cEBPα site prevented the RET-induced increase in hPit1 promoter expression. TaqMan qRT-PCR (real time RT-PCR) for RET, Pit1, Arf, TP53, GDNF, steroidogenic factor 1, and GH was performed in RNA from whole ACRO and NFPA tumors. ACRO but not NFPA adenomas express RET and Pit1. GDNF expression in the tumors was positively correlated with RET and negatively correlated with p53. In conclusion, ACROs maintain an active RET/Pit1/p14Arf/p53/apoptosis pathway that is inhibited by GDNF. Disruption of GDNF's survival function might constitute a new therapeutic route in acromegaly.

Pasireotide therapy in a rare and unusual case of plurihormonal pituitary macroadenoma

We report the use of pasireotide in a rare and unusual case of pituitary macroadenoma co-secreting GH, prolactin and ACTH. A 62-year-old Caucasian man presented with impotence. Clinically, he appeared acromegalic and subsequent investigations confirmed GH excess and hyperprolactinaemia. Magnetic resonance imaging (MRI) of pituitary revealed a large pituitary macroadenoma. He underwent trans-sphenoidal surgery and histology confirmed an adenoma with immunohistochemistry positive for ACTH, GH and prolactin. Acromegaly was not cured following surgery and inadequately controlled despite subsequent octreotide therapy. He underwent further debulking pituitary surgery, following which IGF1 levels improved but still high. This time adenoma cells showed immunohistochemistry positivity for ACTH only, following which subsequent investigations confirmed intermittent hypercortisolaemia compatible with pituitary Cushing's disease. We recommended radiotherapy, but in view of the pluripotential nature of the tumour, we proceeded with a trial of s.c. pasireotide therapy on the basis that it may control both his acromegaly and Cushing's disease. After 3 months of pasireotide therapy, his mean GH and IGF1 levels improved significantly, with improvement in his symptoms but intermittent hypercortisolaemia persists. His glycaemic control deteriorated requiring addition of new anti-diabetic medication. MRI imaging showed loss of contrast uptake within the tumour following pasireotide therapy but no change in size. We conclude that our patient has had a partial response to pasireotide therapy. Long-term follow-up studies are needed to establish its safety and efficacy in patients with acromegaly and/or Cushing's disease.

A GRFa2/Prop1/stem (GPS) cell niche in the pituitary

BACKGROUND

The adult endocrine pituitary is known to host several hormone-producing cells regulating major physiological processes during life. Some candidates to progenitor/stem cells have been proposed. However, not much is known about pituitary cell renewal throughout life and its homeostatic regulation during specific physiological changes, such as puberty or pregnancy, or in pathological conditions such as tumor development.

PRINCIPAL FINDINGS

We have identified in rodents and humans a niche of non-endocrine cells characterized by the expression of GFRa2, a Ret co-receptor for Neurturin. These cells also express b-Catenin and E-cadherin in an oriented manner suggesting a planar polarity organization for the niche. In addition, cells in the niche uniquely express the pituitary-specific transcription factor Prop1, as well as known progenitor/stem markers such as Sox2, Sox9 and Oct4. Half of these GPS (GFRa2/Prop1/Stem) cells express S-100 whereas surrounding elongated cells in contact with GPS cells express Vimentin. GFRa2+-cells form non-endocrine spheroids in culture. These spheroids can be differentiated to hormone-producing cells or neurons outlining the neuroectoderm potential of these progenitors. In vivo, GPSs cells display slow proliferation after birth, retain BrdU label and show long telomeres in its nuclei, indicating progenitor/stem cell properties in vivo.

SIGNIFICANCE

Our results suggest the presence in the adult pituitary of a specific niche of cells characterized by the expression of GFRa2, the pituitary-specific protein Prop1 and stem cell markers. These GPS cells are able to produce different hormone-producing and neuron-like cells and they may therefore contribute to postnatal pituitary homeostasis. Indeed, the relative abundance of GPS numbers is altered in Cdk4-deficient mice, a model of hypopituitarism induced by the lack of this cyclin-dependent kinase. Thus, GPS cells may display functional relevance in the physiological expansion of the pituitary gland throughout life as well as protection from pituitary disease.

Expression of adrenocorticotropic hormone, prolactin and transcriptional factors in clinically nonfunctioning pituitary adenoma

We describe here a case of a clinically nonfunctioning pituitary adenoma, but with expression of ACTH and PRL. A 42-year-old woman was referred to our department for further evaluation of pituitary tumor. She had no acromegaloid features, and no typical Cushingoid features. She had no galactorrhea, and had regular menses. GH, IGF-I, LH, FSH, TSH, ACTH and cortisol levels in blood were all within the normal ranges, while PRL levels were mildly elevated. Both ACTH and cortisol levels were adequately increased in response to CRH, and both were suppressed by a small dose of dexamethasone. Plasma ACTH and cortisol levels were decreased at night, suggesting the circadian rhythms for plasma ACTH levels were undisturbed. Based on these findings we did not clinically suspect ACTH-producing tumor, however immunohistochemistry revealed ACTH immunoreactivity in the pituitary adenoma. Therefore, the tumor was considered a silent corticotroph adenoma. PRL was co-expressed in a significant subpopulation of ACTH-immunoreactive tumor cells. Ptx1, Neuro D1, and T pit were densely expressed and Pit-1 was sparsely expressed in the nuclei of adenoma cells. It is therefore possible that a tumor originating in an immature or uncommited adenohypophysial stem cell may later differentiate into different cell types due to a combination of certain specific transcriptional factors.

A multihormonal pituitary adenoma with growth hormone and adrenocorticotropic hormone production, causing acromegaly and Cushing disease

Pituitary adenoma with growth hormone (GH) and corticotropin (ACTH) production causing apparent acromegaly and Cushing disease is extremely rare. A 45-year-old woman had a pituitary macroadenoma and severe insulin resistance. Physical examination showed a fully developed acromegaly associated with mild Cushingoid features. Serum GH, insulin-like growth factor-I, ACTH, and cortisol levels were all elevated. Hormonal loading tests resulted in GH levels increasing paradoxically in response to thyrotropin-releasing hormone (TRH), but not corticotropin-releasing hormone (CRH). A similar unexpected increase in ACTH and cortisol levels occurred in response to TRH and GH-releasing hormone. After trans-sphenoidal resection of the pituitary macroadenoma immunohistochemistry revealed the presence of either diffuse but faintly GH-positive cells or sparse but distinct ACTH-stained cells. A marked amelioration of insulin resistance was observed postoperatively. The elevated ACTH and cortisol levels should therefore be investigated by CRH and dexamethasone suppression tests for the coexistence of Cushing disease to exclude the possibility of underlying ACTH-producing tumors.

Plurihormonal pituitary adenomas: immunostaining of all pituitary hormones is mandatory for correct classification

AIMS

We studied the clinicopathological characteristics of plurihormonal pituitary adenomas.

METHODS AND RESULTS

The study material included 167 plurihormonal adenomas, which consisted of 31% of the surgically removed pituitary adenomas that we collected during a 12-year period. The mean age of patients with plurihormonal adenoma was 45.7 years (range 13-75 years). There were 86 men and 81 women. All tumours were fully classified by immunohistochemical staining for seven pituitary hormones or subunits. Thirty immunohistochemical subtypes of plurihormonal adenomas were recognized. Hormonal symptoms were present in 70% of patients, while serum hormonal levels were increased in 89% of patients. Most patients had symptoms related to only one of the hormones and only 7% of patients had symptoms related to two hormones. The most common hormonal symptom was acromegaly (50%); symptoms related to hyperprolactinaemia ranked second (20%). Double immunostaining of all the possible combinations of the hormones was performed in 30 selected tumours, and they all showed mixtures of hormones in individual adenoma cells in any hormonal combinations studied. The latter finding supported the view that plurihormonal adenomas are monomorphous adenomas.

CONCLUSIONS

Plurihormonal adenomas are common pituitary adenomas. Immunohistochemical staining of all pituitary hormones is mandatory for correct classification.

From macroprolactinoma to concomitant ACTH-PRL hypersecretion with Cushing's disease

Multiple pituitary hormone hypersecretions have been already described, but the combination of PRL and ACTH excess is rare. This report deals with a 42-yr-old woman affected by macroprolactinoma (PRL 12,720 microg/l, huge tumor with extrasellar extension at imaging). After one year on dopaminergic treatment causing PRL normalization and tumor shrinkage, she developed hypercortisolism (UFC 1,000 microg/24 h, ACTH 200 ng/l). Cushing's disease was diagnosed. After neurosurgery (at immunocytochemistry mixed ACTH-PRL adenoma was shown) hypercortisolism remitted, whereas pathological hyperprolactinemia with tumor remnant in cavernous sinus persisted and hypopituitarism developed. The patient reported seems atypical for the following reasons: 1) the concomitant PRL and ACTH hypersecretions; 2) the clinical presentation with hypercortisolism following hyperprolactinemia; 3) the surgical cure of hypercortisolism with persisting hyperprolactinemia.

Target cells of gamma3-melanocyte-stimulating hormone detected through intracellular Ca2+ responses in immature rat pituitary constitute a fraction of all main pituitary cell types, but mostly express multiple hormone phenotypes at the messenger ribonucleic acid level. Refractoriness to melanocortin-3 receptor blockade in the lacto-somatotroph lineage

Gamma3-MSH has recently been shown to be a biologically active peptide in the rat anterior pituitary. It induces a sustained rise in intracellular free calcium levels ([Ca2+]i) in a relatively small population of immature pituitary cells. The present study was intended to identify the target cells of this peptide and to discern the signal-transducing melanocortin (MC) receptor. In dispersed pituitary cells from 14-day-old rats, increasing doses of gamma3-MSH (0.1, 1, and 10 nM) evoked a sustained oscillating [Ca2+]i rise in an increasing number of cells (up to 14.5%). Within the responsive cells, 53% showed GH immunoreactivity (-ir), 12% showed PRL-ir, 2% showed TSHbeta-ir, 5% showed LHbeta-ir, and 10% showed ACTH-ir, whereas 18% did not express any hormone-ir to a detectable level. As assessed by single cell RT-PCR for the presence of pituitary hormone messenger RNA (mRNA), 26% of the gamma3-MSH-responsive cells contained only GH mRNA, 5% contained only PRL mRNA, and 4% contained only TSHbeta mRNA. Twenty-two percent contained mRNA of GH, PRL, and TSHbeta in various dual or triple combinations. About 24% of the gamma3-MSH-responsive cells expressed POMC mRNA, mostly together with other mRNAs, i.e. with GH mRNA and/or PRL mRNA or with mRNA of GH, PRL, and TSHbeta. Eighteen percent of the responsive cells expressed LHbeta, all of them together with mRNA of GH, PRL, and TSHbeta in various combinations. The absence of hormone mRNA was found in less than 1% of the responsive cells. In cells chosen at random (representative of the total pituitary cell population), the proportion of cells expressing two or multiple hormone mRNAs was twice as low as that in the gamma3-MSH-responsive population, whereas the proportion of cells expressing a single hormone mRNA was twice as high (about two thirds of all cells). Moreover, unlike in the gamma3-MSH-responsive cell population, randomly chosen cells were found that coexpressed POMC mRNA with LHbeta mRNA. The effect of gamma3-MSH on [Ca2+]i was blocked by the MC-3 receptor antagonist SHU9119 (used up to a 1000-fold excess) in 46% or less of the responsive cells. SHU9119 failed to block the [Ca2+]i response to gamma3-MSH in PRL-, GH-, and TSHbeta-ir cells, but it did block the response in most ACTH-ir cells and in cells expressing no hormone to a detectable level. Single cell RT-PCR revealed that expression of MC-3 receptor mRNA was detected in only 16% of gamma3-MSH-responsive cells. The present data suggest that the target cells of gamma3-MSH in terms of [Ca2+]i responses in the immature rat pituitary constitute subpopulations of all main pituitary cell types, including nonhormonal (or low expression hormonal) cells. However, in contrast to the total pituitary cell population, most of these cells display multilineage gene activation at the mRNA level, i.e. express mRNA of GH, PRL, TSHbeta, POMC, and LHbeta in dual, triple, or quadruple combinations. Although gamma3-MSH may act through the MC-3 receptor in a portion of these cells, most of these cells (mainly in the lacto-somatotroph lineage) may transduce the signal through another receptor or through an MC-3 receptor with unconventional binding characteristics.