Intrasellar hamartoma associated with pituitary adenoma

Observation of Clinicopathologic Features of Pituitary Adenoma With Neuronal Differentiation

OBJECTIVE

To investigate the clinicopathologic features of pituitary adenoma with neuronal differentiation.

METHODS

Four patients with mixed gangliocytoma-pituitary adenomas between January 2011 and January 2021 and 111 new-onset patients with adenomas between January 2019 and June 2021 who attended the First Affiliated Hospital of Fujian Medical University were included in the study. The histological and immunohistochemical findings were analyzed. Neuronal differentiation marker staining was performed on new-onset adenomas, and the related literature was reviewed.

RESULTS

Altogether, more than 100 mixed gangliocytoma-pituitary adenoma cases have been reported in the literature until now, of which pituitary-specific POU-class homeodomain transcription 1 (PIT1) positive adenomas are more frequently observed. In the present study, all 4 patients we described were female, aged 29 to 53 years (mean 39 years). Clinically, 3/4 patients presented with acromegaly, and 1/2 patients presented with headache. Histologically, the tumor was composed of two distinct mixed components. The one was a population of neoplastic ganglionic cells with large nuclei, prominent nucleoli, and abundant basophilic cytoplasm embedded in a fibrillary background. Stains of chromograninA (CgA), synaptophysin (Syn), Calretinin (CR) were positive. Axotomy-like expression was observed in neurofilament (NF) staining. PIT1 was expressed in partial ganglionic cells in all cases. The other component was a population of small uniform cells with round nuclei and acidophilic cytoplasm. Prolactin (PRL) and growth hormone (GH) were positive in all 4 cases. PIT1 was positive in the nuclei of adenomas. Although adenomas and ganglionic regions varied in histology, there was a population of cells with neuronal differentiation expressing PIT1. Additionally, axotomy-like expression of NF staining could be seen in a distant area of adenoma regions. A total of 111 cases of adenomas without ganglionic cells were included in this study, including 7 cases with neuronal differentiation. Among them, 4 cases were prolactinomas, 2 cases were somatotroph adenomas, and 1 case was corticotroph adenoma. 6/7 cases were PIT1-positive adenomas. And the remaining one case is T-PIT-positive adenoma.

CONCLUSIONS

Mixed gangliocytoma-pituitary adenomas are rare tumors with neuronal differentiation. The majority of MGAs are associated with endocrinopathies, mainly acromegaly. Our results suggest that PIT1-positive pituitary adenomas may have neural differentiation potential, which may not be unusual. This indication supports the possibility that the neuronal transdifferentiation of adenomatous cells is a possible mechanism, and the underlying mechanism requires further elucidation.

Acromegaly Caused by Ectopic Growth Hormone Releasing Hormone Secretion: A Review

INTRODUCTION

Ectopic acromegaly is a rare condition caused most frequently by growth hormone releasing hormone (GHRH) secretion from neuroendocrine tumors. The diagnosis is often difficult to establish as its main symptoms do not differ from those of acromegaly of pituitary origin.

OBJECTIVES

To determine most common clinical features and diagnostic challenges in ectopic acromegaly.

PATIENTS AND METHODS

A search for ectopic acromegaly cases available in literature was performed using PubMed, Cochrane, and MEDline database. In this article, 127 cases of ectopic acromegaly described after GHRH isolation in 1982 are comprehensively reviewed, along with a summary of current state of knowledge on its clinical features, diagnostic methods, and treatment modalities. The most important data were compiled and compared in the tables.

RESULTS

Neuroendocrine tumors were confirmed in 119 out of 121 patients with histopathological evaluation, mostly of lung and pancreatic origin. Clinical manifestation comprise symptoms associated with pituitary hyperplasia, such as headache or visual field disturbances, as well as typical signs of acromegaly. Other endocrinopathies may also be present depending on the tumor type. Definitive diagnosis of ectopic acromegaly requires confirmation of GHRH secretion from a tumor using either histopathological methods or GHRH plasma concentration assessment. Hormonal evaluation was available for 84 patients (66%) and histopathological confirmation for 99 cases (78%). Complete tumor resection was the main treatment method for most patients as it is a treatment of choice due to its highest effectiveness. When not feasible, somatostatin receptor ligands (SRL) therapy is the preferred treatment option. Prognosis is relatively favorable for neuroendocrine GHRH-secreting tumors with high survival rate.

CONCLUSION

Although ectopic acromegaly remains a rare disease, one should be aware of it as a possible differential diagnosis in patients presenting with additional symptoms or those not responding to classic treatment of acromegaly.

Hypothalamic hormone-producing tumors

The hypothalamus is functional neuroendocrine tissue that is responsible for the synthesis and secretion of peptide hormones that regulate the pituitary and other endocrine functions. Endocrine tumors of the hypothalamus are rare but they provide a model for tumors that have both structural and functional effects. Patients with hypothalamic endocrine tumors suffer mass effects including headaches, visual disturbances, and endocrine dysfunction due to structural damage to hypothalamic nuclei, which regulate appetite, temperature, diurnal rhythms and emotions. In addition, these tumors can secrete hormones that can cause acromegaly, Cushing disease, hyperprolactinemia, and the syndrome of inappropriate antidiuresis. Morphologic classification of these tumors has provided evidence for two classes of tumors, gangliocytomas that are composed of large neurons and neurocytomas that are comprised of small cells; these resemble the variants of magnocellular and parvocellular neurons in the hypothalamic nuclei. Biomarkers are used to classify these tumors and achieve accurate structure-function correlations. While surgery remains the mainstay of therapy, novel medical and radiopharmaceutical approaches are available for patients with progressive and/or unresectable tumors.

Hypothalamic Endocrine Tumors: An Update

The hypothalamus is the site of synthesis and secretion of a number of endocrine peptides that are involved in the regulation of hormonal activity of the pituitary and other endocrine targets. Tumors of the hypothalamus have been recognized to have both structural and functional effects including hormone hypersecretion. The classification of these tumors has advanced over the last few years, and biomarkers are now available to classify these tumors and provide accurate structure-function correlations. This review provides an overview of tumors in this region that is critical to metabolic homeostasis with a focus on advances in the diagnosis of gangliocytomas, neurocytomas, and pituicytomas that are unique to this region.

Mixed gangliocytoma-pituitary adenoma containing GH and GHRH co-secreting adenoma cells

SUMMARY

A 67-year-old woman with a past history of type 2 diabetes mellitus presented with worsening glycemic control. She had some acromegaly symptoms and magnetic resonance imaging demonstrated a pituitary tumor. Endocrinological examination found the resting growth hormone (GH) level within the normal range, but elevated insulin-like growth factor 1 level. A 75 g oral glucose tolerance test showed inadequate suppression of nadir GH levels. Acromegaly due to GH-secreting pituitary tumor was diagnosed. The patient underwent endoscopic transsphenoidal surgery resulting in gross total removal of the tumor and recovered well postoperatively. Histological examination of the tumor showed coexistence of relatively large gangliocytoma cells and pituitary adenoma cells, suggesting mixed gangliocytoma-pituitary adenoma. In addition, colocalization of GH and GH-releasing hormone (GHRH) in pituitary adenoma cells was revealed, so the adenomatous components were more likely to produce GHRH in our mixed gangliocytoma-pituitary adenoma case. Mixed gangliocytoma-pituitary adenoma is very rare, and the present unique case demonstrated only the adenomatous components associated with GHRH production.

LEARNING POINTS

Sellar gangliocytoma coexisting with pituitary adenoma is recognized as a mixed gangliocytoma-pituitary adenoma and is very rare. A proposed developmental mechanism of growth hormone (GH)-secreting mixed gangliocytoma-pituitary adenoma involves GH-releasing hormone (GHRH) produced by the gangliocytic components promoting the growth of tumor including GH-secreting adenomatous components. Since our present case indicated that the adenomatous components of mixed gangliocytoma-pituitary adenoma could secrete both GH and GHRH simultaneously, progression of GH-secreting mixed gangliocytoma and pituitary adenoma may involve exposure to spontaneously produced GHRH due to the adenomatous components.

Mixed gangliocytoma-pituitary adenoma in the sellar region: a large-scale single-center experience

BACKGROUND

Mixed gangliocytoma-pituitary adenoma is an extremely rare tumor occurring in the sellar region, histologically composed of both gangliocytic and pituitary adenomatous architectures. The histogenesis of these tumors remains unknown, and the diagnosis, treatment, and prognosis are yet to be fully understood.

METHODS

We retrospectively reviewed the clinical, radiological, and histopathological profiles from a series of 20 patients with sellar mixed gangliocytoma-pituitary adenomas. All patients underwent surgical tumorectomy via an endoscopic or microscopic transsphenoidal approach. Perioperative magnetic resonance imaging (MRI) and computed tomography (CT) data were reviewed. Immunohistochemical stains and electron microscopy examination were performed. Follow-up outcomes were presented.

RESULTS

This case series consisted of 13 females and seven males (age range, 20-59 years; mean age, 42.3 ± 11.2 years). Preoperative endocrine examination showed elevated growth hormone (GH) in nine patients and hyperprolactinemia in eight patients. The tumors were positive for GH in 15 cases, prolactin in 13 cases, adrenocorticotropic hormone in three cases, and thyroid-stimulating hormone in one case. Gross total resection was achieved in 15 patients, and subtotal resection in five patients. During an average follow-up period of 42.5 ± 29.0 months, no recurrence was noted.

CONCLUSIONS

The clinical and neuroimaging features of sellar mixed gangliocytoma-pituitary adenomas are non-specific, and invasion into the cavernous sinus is common. Surgical resection via a transsphenoidal approach is the preferred treatment, and the surgical outcomes are favorable. Moreover, our histopathological findings are more likely to support the theory that mixed gangliocytoma-pituitary adenoma originates from the neuronal transdifferentiation of adenomatous cells.

Transsphenoidal Surgery for Mixed Pituitary Gangliocytoma-Adenomas

BACKGROUND

Most sellar gangliocytomas are discovered with a concurrent pituitary adenoma, also known as a mixed gangliocytoma-adenoma (MGA). MGAs are rare, with fewer than 100 cases reported in the literature to date and only 1 previously documented surgical series. Because MGAs are radiologically indistinguishable from pituitary adenomas, they are often diagnosed after surgery. Combined with the paucity of clinical outcome data for these tumors, this makes their diagnosis and management challenging. Here we describe the clinical presentation and outcomes of 10 individuals who were diagnosed with a MGA at a single institution.

METHODS

This retrospective case series study included patients diagnosed with a combined sellar MGA between 1993 and 2016.

RESULTS

This series comprised 10 patients, mean age of 44 years (range, 28-63 years) diagnosed with an MGA. The mean tumor size was 1.6 cm (range, 0.4-2.4 cm). Five patients presented with acromegaly, and 1 patient had recurrent Cushing disease. Transsphenoidal surgery was performed in all cases, and gross total resection was achieved in 7 patients (70%). Histologically, 9 of the 10 MGAs were identified as mixed somatotroph adenoma-gangliocytomas. The median duration of follow-up was 74 months (range, 2-180 months). Following adjuvant treatment (n = 3), all patients with acromegaly (n = 4) achieved biochemical remission, and no patient experienced recurrence of the pituitary tumor with a median radiographic follow-up of 48 months.

CONCLUSIONS

MGAs are often associated with a hypersecretory adenoma. Transsphenoidal surgery is well tolerated by most patients, and when performed in combination with adjuvant therapy, a low rate of recurrence and reversal of preoperative endocrinopathy can be expected.

Anterior Gray Matter Pituicytic Heterotopia with Monomorphic Anterior Pituitary Cells: A Variant of Nonsecretory Pituitary Adenoma Neuronal Choristoma? Report of a Rare Case and Review of the Literature

BACKGROUND

Mixed tumors of adenomatous and neuronal cells in the sellar region are an uncommon finding. The origins of these heterogeneous tumors are unknown, and management remains unsettled. We report a very rare case of anterior gray matter pituicytic heterotopia with monomorphic anterior pituitary cells that likely represents a variant of nonsecreting pituitary adenoma neuronal choristoma (PANCH) with no ganglion cells. We also review the current literature for the various clinical presentations of PANCH.

CASE DESCRIPTION

A 49-year-old female complaining of headache, blurred vision, and hair loss was found to have a nonsecretory sellar mass with compression of the optic chiasm on magnetic resonance imaging (MRI). The mass was excised via a transsphenoidal procedure. Histological analysis of tissue sections revealed heterotopic gray matter with reactive gliosis without ganglion cells or Herring bodies. Only 1 smear exhibited characteristics of a pituitary adenoma.

CONCLUSIONS

The overall findings were most consistent with a variant of PANCH. At a postoperative follow-up of 4.5 years, there was resolution of visual symptoms, and the residual sellar mass was stable on MRI. Neuronal choristoma is hypothesized to originate from embryonal pituitary or hypothalamus, or by differentiation from pituitary adenoma cells. Surgery is the cornerstone of management, and the clinical course appears to be similar to that of nonfunctioning pituitary adenoma in reported cases.

Homology of insect corpora allata and vertebrate adenohypophysis?

Animal species of various phyla possess neuroendocrine glands whose hormonal products regulate developmental and physiological mechanisms and directly impact behavior. Two examples, the corpora allata of insects and the vertebrate adenohypophysis have previously been regarded as analogous tissues that evolved independently from diffuse epidermal nerve nets of early metazoans. More recent developmental and functional studies accumulated evidence suggesting that the bilaterian nervous systems including its modern parts (e.g. pallium or cortex and mushroom bodies) and its neuroendocrine appendages (that are considered to be more ancient structures) possess a single evolutionary origin. The corpora allata of insects and the vertebrate adenohypophysis share a number of characteristics in respect of morphology, control of hormone release by RFamides, metabolites produced by closely related cytochrome P450 enzymes and gene expression during embryonic development. This review incorporates latest findings into an extensive description of similarities between insect corpora allata and vertebrate adenohypophysis that should encourage further studies about the onto- and phylogenetic origin of these neuroendocrine glands.

Combined sellar fibrosarcoma and prolactinoma with neuronal metaplasia: report of a case unassociated with radiotherapy

We report the occurrence of a primary pituitary fibrosarcoma causally unrelated to radiotherapy, admixed in association with a prolactin cell pituitary adenoma showing neuronal metaplasia. These unique findings were associated with multiple endocrine neoplasia type 1 (MEN 1). Primary fibrosarcoma involving the sella is a very rare tumor. The majority of cases have been associated with prior irradiation of either a pituitary adenoma or a craniopharyngioma. Pituitary adenoma with neuronal metaplasia is also rare and usually occurs in the setting of acromegaly. Despite the intimate association of both elements in our lesion, no transition of adenoma to sarcoma was demonstrable by immunohistochemistry or in situ hybridization studies.

Prolactin-producing pituitary adenoma and carcinoma with neuronal components--a metaplastic lesion

Recent studies indicate that cells of various epithelial tumors are capable of transformation to neurons. Observing both neurons and neuropil in two prolactin-producing adenohypophyseal tumors, one benign and one malignant, we sought to assess their cellular differentiation, the presence of nerve growth factor receptor, and expression of the dopamine receptor gene using immunocytochemistry, electron microscopy, and in situ hybridization. Light and electron microscopy clearly revealed cells morphologically transitional between adenoma/carcinoma cells and neurons. Large neurons lacked proliferative activity. Neurons in varying number showed immunoreactivity for pituitary hormones including prolactin, growth hormone and alpha subunit in the adenoma and prolactin alone in the carcinoma. The distribution of nerve growth factor receptor staining was similar. In both tumors, in situ hybridization showed mRNAs for prolactin and dopamine receptor within adenohypophyseal cells and neurons. Our results indicate that the occurrence of neurons and neuropil in growth hormone and prolactin-producing pituitary tumors appears to be the result of metaplasia. The process is not limited to benign tumors and may be due to the production of tropic substances by the adenohypophysial cells, which by paracrine/autocrine mechanisms result in transformation of adenoma cells to nerve cells.

Hypothalamic hamartoma: report of a case with unusual histologic features

A rare case of hypothalamic hamartoma with unusual radiologic and histopathological features is described, possibly the first of its type in English literature. A 1.5-year-old female child presented with precocious puberty. MR scan of the brain revealed a pedunculated hypothalamic mass, most of which was isointense with normal brain on T1- and T2-weighted images. However, a sizeable component of the lesion was hyperintense on T1-weighted images, suggestive of adipose tissue. Microscopically, the lesion was a hamartoma composed of an admixture of neuroectodermal elements, namely glial cells, neurons, and nerve bundles along with mesenchymal elements in the form of fibroadipose tissue.

Differentiating neuroblastoma of pituitary gland: neuroblastic transformation of epithelial adenoma cells. Case report

The authors report the case of a 40-year-old woman with a 12-year history of irregular menses, amenorrhea, infertility, galactorrhea, a slightly elevated prolactin level, and a slowly growing pituitary adenoma. She developed recent onset of visual symptoms, prompting craniotomy for removal of an intrasellar tumor. Following surgery, her vision and prolactin levels returned to normal. Light microscopic and immunohistochemical examination of the tumor revealed it to be a neuroblastoma, which was immunohistochemically positive for synaptophysin, S-100 protein, and oxytocin. The neoplasm contained prolactin-positive neuroblastic and pituitary epithelial cells. No other pituitary hormones were found. Electron microscopy demonstrated two cell types: one with frequent neuritic processes containing neurosecretory granules and showing synaptic specialization, and another one compatible with epithelial adenohypophyseal cells. A few cells had ultrastructural features that were transitional between neuronal cells and granulated epithelial cells. Agranular folliculostellate cells were also identified. Immunoelectron microscopy demonstrated prolactin granules in the cytoplasm of the epithelial cells, in a few transitional cells, and in scattered neuritic processes. Ultrastructural and immunohistochemical features of the tumor suggested a transformation of pituitary epithelium to neuroblastic cells. Hyperprolactinemia and associated clinical symptoms may in part be attributed to selective prolactin secretion by neoplastic cells that were differentiating into adenomatous pituitary cells and, to a lesser extent, to cells differentiating into a neuroblastic line. Compression of pituitary stalk might also have been a contributory factor to the increased prolactin levels. Moreover, the oxytocin produced by the neuroblastic cells was considered an additional stimulus for prolactin secretion by neoplastic cells or by the normal pituitary.

Intrasellar neuronal choristoma associated with growth hormone-producing pituitary adenoma containing amyloid deposits

The histological, immunocytochemical, and ultrastructural features of an intrasellar neuronal choristoma associated with pituitary growth hormone (GH)-producing adenoma are reported. Immunohistochemistry studies and electron microscopy examination showed the adenoma cells to be positive for GH but negative for prolactin, and the neurons of the choristoma to have GH-releasing factor (GRF) neurosecretory activity. The adenoma also had many amyloid deposits in its extracellular space immunoreactive to GRF. This is the first report of the tumor containing amyloid deposits.

Smith-Lemli-Opitz syndrome type II: report of a case with additional radiographic findings

A phenotypically female infant with 46-XY chromosomes was found to have Smith-Lemli-Opitz syndrome, type II a rare congenital malformation syndrome with many features of the more common classic Smith-Lemli-Opitz syndrome. The patient's skeletal survey revealed characteristic and previously undescribed skeletal anomalies which are reported. In addition a lipoma of the pituitary gland was found on magnetic resonance imaging. This lesion is particularly interesting given the hypothesized steroid abnormality in Smith-Lemli-Opitz, type II syndrome, the sexual ambiguity of males with this syndrome and the similarity of this syndrome to the Pallister-Hall syndrome which characteristically has a hamartoblastoma of the hypothalamus.