A mixed functional microadenoma and ganglioneuroma of the pituitary fossa. Case report

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.

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.

Trigeminal Ganglioneuroma: A Rare Case of Trigeminal Neuralgia Caused by Cerebellopontine Angle Tumor

BACKGROUND

Intracranial ganglioneuromas are very rare benign tumors of neural crest origin and generally arise from the peripheral nervous system or adrenal glands. Very few cases of intracranial ganglioneuroma arising from the trigeminal nerve have been reported in the literature, all in East Asia.

CASE DESCRIPTION

A 52-year-old male presented to his primary care physician for evaluation of right facial and periorbital pain for over 18 months. He also reported a two-week history of diplopia with right lateral gaze, which resolved spontaneously. An MRI brain with and without contrast revealed a 3.0 × 2.6 × 2.4 cm enhancing extra-axial mass involving right Meckel's cave with a posterior 1.0 × 1.4 cm lobular component protruding into the prepontine cistern. The patient underwent a right middle fossa craniotomy for a subtemporal surgical resection of the tumor. Histologic section of the tumor demonstrated mature ganglion cells with surrounding satellite cells in a schwannian rich stroma, consistent with mature type ganglioneuroma.

CONCLUSIONS

To the best of our knowledge, this is the sixth case of trigeminal ganglioneuroma; however, it is the first case reported in the United States.

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.

Ganglioneuroma of the sphenoid wing: a case report and literature review

Ganglioneuromas (GNs) are well-differentiated, slow-growing, benign tumors that are quite rare and usually found in the posterior mediastinum and retroperitoneum. They are composed of ganglion and Schwann cells and their origin remains in dispute. GNs have been reported as intraosseous lesions, such as in temporal and orbital bones. There are rare reports of intracranial lesions, mostly in the pituitary fossa. Most GN patients are children and are clinically asymptomatic. Diagnosis of GN requires histopathologic evaluation since no specific clinical or radiologic diagnostic features have been identified. We report the case of a 35-year-old man with recurrent sinusitis whose radiologic workup revealed a lytic right sphenoid wing lesion with microcalcifications. He underwent gross-total resection of the lesion and the pathologic findings were diagnostic of ganglioneuroma. To the best of our knowledge, this is the first reported case of sphenoid wing GN. The nature and origin of this tumor are discussed, and the GN literature is reviewed.

Sellar neuroblastoma mimicking pituitary adenoma

OBJECTIVE AND IMPORTANCE

Primary intracranial neuroblastomas are rare. They generally arise in the supratentorial parenchyma or paraventricular region. Even more rare are primary sellar neuroblastomas. We present a neuroblastoma that arose in the sellar region and mimicked a non-functioning pituitary adenoma.

CLINICAL PRESENTATION

This 33-year-old man presented with bitemporal hemianopsia. MRI showed a sellar mass with suprasellar extension mimicking a pituitary adenoma.

INTERVENTION

Because of tumor recurrence and dissemination to the cervical region, he underwent 6 operations and radiosurgery. Detailed histologic examination confirmed the diagnosis of neuroblastoma. Postoperative conventional radiotherapy was effective in reducing the size of the tumor.

CONCLUSION

Neuroblastoma should be considered in the differential diagnosis of patients with sellar lesions.

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.

Gangliocytoma masquerading as a prolactinoma. Case report

The authors describe the case of a 36-year-old man who presented with bitemporal hemianopsia and a serum prolactin concentration of 1440 ng/ml. Magnetic resonance imaging of the pituitary revealed a presumed macroadenoma with suprasellar and temporal lobe extension. Although the patient's prolactin level was lowered to 55 ng/ml by bromocriptine therapy, no tumor shrinkage occurred. Fourteen months later, progression of visual field defects necessitated transsphenoidal resection, which was incomplete. Immunocytochemical analysis of the biopsy tissue was positive for prolactin and, in view of the clinical picture, more detailed analysis was not performed. External-beam radiotherapy was given 2 years later because of enlargement of residual tumor. Subsequently, despite a fall in the serum prolactin concentration to less than 20 ng/ml in response to the course of bromocriptine, the mass displayed further extension into the temporal lobe. Nine years after the patient's initial presentation, he underwent transfrontal craniotomy for sudden deterioration in visual acuity caused by hemorrhage into the mass. No adenohypophyseal tissue was identified in the resected tissue. The mass was composed of dysplastic neurons that were strongly immunoreactive for synaptophysin and neurofilament (indicating neural differentiation) and prolactin. Review of the original biopsy specimen indicated that the prolactin-positive cells had striking neuronal morphological characteristics. The final diagnosis in this case is prolactin-secreting gangliocytoma. Although exceedingly rare, this disease must be added to the differential diagnosis in cases of "prolactinoma" when bromocriptine therapy is followed by a marked decline in serum prolactin that is not accompanied by significant tumor shrinkage. Furthermore, in such instances, consideration should be given to "obtaining a biopsy sample prior to electing for radiotherapy.

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.

Intrasellar pituitary gangliocyto-adenoma presenting with acromegaly: case report

OBJECTIVE AND IMPORTANCE

A gangliocytoma in the sellar region is extremely rare. We describe a rare case of intraseller gangliocytoma coexisting with a growth hormone-producing pituitary adenoma, which presented with acromegaly.

CLINICAL PRESENTATION AND INTERVENTION

A 64-year-old woman was admitted to our hospital with headache and acromegaly. Endocrinological studies revealed an elevated serum level of growth hormone (GH). Magnetic resonance imaging showed a tumor at the intrasellar and suprasellar regions. The tumor was totally removed via a transsphenoidal approach.

RESULTS

A histological examination of the resected specimen showed areas of ganglionic cells and adenomatous cells. Immunohistochemical examination demonstrated GH-releasing hormone-positive ganglionic cells and GH-positive pituitary adenoma.

CONCLUSION

Based on these immunohistochemical findings, we hypothesized that the intrasellar gangliocytoma promoted the growth of the pituitary adenoma, which had been transformed from a region of pituitary hyperplasia by chronic overstimulation from excess GH-releasing hormone produced by the intrasellar gangliocytoma.

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.

Pituitary adenoma with neuronal choristoma (PANCH): composite lesion or lineage infidelity?

Fifteen cases of the rare association of pituitary adenoma and neuronal choristoma (PANCH) were investigated by histology, immunohistochemistry, and electron microscopy. Acromegaly was apparent clinically in 11 patients and was equivocal in 1, and 3 lesions appeared to be nonfunctioning. Histology revealed various proportions of chromophobic PA and nervous tissue consisting of neuronlike cells and neuropil. Immunohistochemistry documented growth hormone (GH) in every PA, including those unassociated with clinical acromegaly. In contrast, the NCH component showed no consistent immunohistochemical profile. Most frequent reactivities were for the pituitary hormone alpha subunit, thyroid-stimulating hormone, and GH, whereas only a few cases displayed scattered positivity for GH-releasing hormone. Low-molecular weight keratin tested positive in PAs and in a few cells and processes of an NCH. A few fibrous bodies were immunoreactive for neurofilament protein. Electron microscopy revealed sparsely granulated GH cell adenoma, neurons, and neuropil. Cells intermediate between PA and neurons were numerous in 1 lesion. The present morphologic findings as well as lack of GH cell hyperplasia and the consistent association of NCH with but one type of PA do not support the causative role of NCH in the initiation of PA, as proposed previously. It appears that NCH is the result of neuronal differentiation within sparsely granulated GH cell adenomas.

Cushing's disease in a child caused by a corticotropin-releasing hormone-secreting intrasellar gangliocytoma associated with an adrenocorticotropic hormone-secreting pituitary adenoma

Cushing's disease resulting from intrasellar corticotropin-releasing hormone (CRH)-secreting gangliocytomas is very rare, and only two such cases have been reported in the literature to date. The authors present a third case in which an adrenocorticotropic hormone-secreting pituitary adenoma was found in addition to a gangliocytoma in a 10-year-old girl with clinical and endocrinological symptoms of Cushing's disease. Computed tomographic and magnetic resonance imaging scans showed a suprasellar and parasellar tumor. A green-colored, heterogeneous tumor and a small adenoma were removed transsphenoidally. Histological examination revealed a large gangliocytoma immunoreactive for CRH and a small, mucoid cell pituitary adenoma immunoreactive for ACTH. This is the first case of such a tumor causing Cushing's disease in a child. It might exemplify induction of an ACTH-secreting pituitary adenoma by means of chronic overstimulation of CRH.

Intrasellar hamartoma associated with pituitary adenoma

The histological, ultrastructural and immunocytochemical features are reported of an intrasellar neuronal and lipomatous hamartoma associated with pituitary growth hormone (GH) cell adenoma and acromegaly. Electron microscopy demonstrated a close contact between neurons and adenomatous GH cells. By immunohistochemistry the adenoma cells revealed a positive staining for GH and prolactin. The neurons of hamartoma showed neurosecretory activity which might have induced the development of pituitary GH cell adenoma.

Intrasellar gangliocytoma with multiple immunoreactivities

The authors report a rare case of intrasellar gangliocytoma without endocrinopathy. The tumor, removed by transsphenoidal surgery, exhibited immunoreactivities for VIP and galanin in the cytoplasm of several nerve cells, a-subunit, somatostatin, and serotonin in the cytoplasm of few nerve cells. Our case indicates that gangliocytomas can produce unusual combinations of peptides which, despite their known biologic activity, do not invariably cause clinical abnormalities.

Mixed gangliocytoma-adenoma: a distinct neuroendocrine tumor of the pituitary fossa

A mixed gangliocytoma-adenoma occurring in the pituitary fossa of a patient who presented with acromegaly, galactorrhea, and headaches is described. Immunohistochemical studies demonstrated the gangliocytic portion of the tumor to be composed nearly entirely of ganglion cells enmeshed in their neuritic processes and disclosed focal presence of growth hormone and prolactin-secreting cells in the adenoma. Ultrastructurally, some of the larger ganglion cells contained (and were often filled with) zebra-like bodies, while the adenoma was shown to be sparsely granulated with numerous fibrous bodies. These findings support the term of mixed gangliocytoma-adenoma for these rare intrasellar tumors and provide additional support for their nature as independent neuroendocrine units.

Intrasellar gangliocytoma containing gastrin and growth hormone-releasing hormone associated with a growth hormone-secreting pituitary adenoma

A 74-year-old acromegalic found to have an intrasellar gangliocytocytoma and GH-secreting pituitary adenoma is described. The gangliocytoma contained immunoreactive gastrin and, to a lesser extent, GHRH, and the adenoma immunostained for GH. Gastrin has not been previously reported in hypothalamic gangliocytomas. Since this peptide has been demonstrated in normal hypothalamus and pituitary, and provokes GH release when administered intraventricularly, it may have caused GHRH release from the gangliocytoma by a local paracrine action and led to adenoma formation and acromegaly.

Immunocytochemistry of four mixed pituitary adenomas and intrasellar gangliocytomas associated with different clinical syndromes: acromegaly, amenorrhea-galactorrhea, Cushing's disease and isolated tumoral syndrome

Four tumors consisting of pituitary adenomatous cells (AD) intricated with ganglion cells (GC) were studied. Each case was associated with a different clinical syndrome: acromegaly, amenorrhea-galactorrhea, Cushing's disease and isolated tumoral syndrome with no hormonal hypersecretion. (a) In the case with acromegaly, immunoreactive growth hormone (IR-GH) was present in 80% of AD. IR-vasoactive intestinal peptide (VIP) was found in 5%-10% of AD and in few GC. Rare GC and processes showed IR-GH-releasing hormone (GRH), -somatostatin (SRIH), -gonadotropin-releasing hormone and -adrenocorticotropin-releasing hormone. (b) In the case with amenorrhea-galactorrhea, IR-prolactin (PRL) was seen in 90% of AD. IR-PRL and -VIP were present in rare GC. (c) In the case with Cushing's disease, 60% of AD and very few GC contained IR-adrenocorticotropin (ACTH) and beta-lipotropin. Rare GC processes contained IR-SRIH. (d) In the case without pituitary hormone hypersecretion, PRL was localized in rare AD and GC. Pituitary hormone and neuropeptides were never colocalized in the same cells. No case displayed IR-neurophysins or -thyroliberin. Pituitary hormones were localized by ultrastructural immunogold labeling. These findings show that: (i) in three cases, pituitary hormones (PRL and ACTH), and, in one case, VIP could be localized in both adenomatous and ganglion cells; (ii) the pituitary hormone-containing cells in the tumors could be related to the hypersecretory syndromes; (iii) intratumoral IR-VIP and -GRH might be involved in GH and PRL hypersecretion in the cases with acromegaly and amenorrhea-galactorrhea.

Cerebral gangliocytoma. An ultrastructural study

We report a case of cerebral gangliocytoma (GC) with a variety of unusual structures in the tumor cells. Light microscopically, the tumor consisted of typical ganglion cells, atypical cells which has argyrophilic granules in the cytoplasm, and a few astrocytes. Electron microscopically, the tumor cells showed typical gangliocytic features, which had abundant rough endoplasmic reticula, ribosomes and cored vesicles of 90-150 nm diameter, a few 50-nm-diametered non-cored vesicles, and other common organelles in their cytoplasm. Furthermore, neoplastic ganglion cells contained a variety of abnormal structures, including membranous cytoplasmic bodies (MCB), Zebra bodies (ZB), tubular structures, branched tubular structures (BTS), concentrical laminated bodies and curvilinear bodies (CB). The MCB, ZB and CB resembled those in GM2 gangliosidosis (GMG), and the BTS that in infantile neuroaxonal dystrophy (INAD). Although the significance of these inclusions is still unknown, it is considered that some common mechanism might play a role in the metabolism of both neoplastic neuronal cells and degenerating neurons (GMG and INAD). Synapses could not be observed anywhere despite complete neuronal differentiation of many tumor cells.

Acromegaly associated with suprasellar and pulmonary hemangiopericytomas. Case report

The authors report the case of a 35-year-old acromegalic woman who developed amenorrhea and decreased left vision, and who was found to have suprasellar and pulmonary hemangiopericytomas. Total removal of the suprasellar hemangiopericytoma resulted in normalization of the plasma human growth hormone (GH) level and a marked decrease in size of the pulmonary hemangiopericytoma. Immunoperoxidase studies for GH and human hypothalamic growth hormone-releasing factor (GHRF) demonstrated immunoreactive intracellular GH only in the suprasellar hemangiopericytoma, with no immunoreactive intracellular GHRF evident in either the suprasellar or pulmonary hemangiopericytoma.

Galactorrhea in the adolescent

Inappropriate lactation--that which occurs beyond the usual postpartum or breast-feeding period or in the male--has been of medical interest for centuries. There is a suggestion that the first recorded case occurred in the Bible in the Book of Esther wherein Mordecai may have breast-fed his niece Esther [1,2]. The Talmud describes a man who nursed his infant after his wife's death during childbirth [3]. Lactation in virgin women was noted by the early Greeks [4], and Aristotle observed lactation in men [5]. The phenomenon of "witch's milk," seen in the newborn, was described as early as 1684 by Bonetus [6]. The first alleged pediatric case of nonpuerperal lactation was of an 8-year-old girl who was able to suckle her baby brother as reported in the 18th Century by Baudelocque [7]. Subsequently, many other cases of abnormal lactation were described in the 19th and early 20th centuries [7-10]. In the past 15 years, there has been a vast proliferation of cases and studies concerning galactorrhea of both sexes [11]. The advent of the prolactin radioimmunoassay was the single most important factor behind the profusion of these investigations [11-14]. Most recently, attention has focused on the high incidence of pituitary tumors--specifically the prolactinoma--in women and to some degree in men [13,15]. The occurrence of such tumors in children and adolescents is also receiving more attention [16,17]. The purpose of this review is to update the reader on galactorrhea with a specific emphasis on: 1) outlining the various causes of galactorrhea that may be seen in adolescent patients; 2) describing the work-up and management of both the male and female adolescent patient with galactorrhea; and 3) describing what is known about the natural history of galactorrhea. A brief description of the physiology of the hypothalamic-pituitary-breast axis and lactation is also presented.

Histological classification of pituitary disease

Morphological features of pituitary disease are classified according to increased and decreased hormone production to allow clinical correlation with pathological processes. Increased hormone synthesis and secretion may be due to pituitary adenomas or carcinomas derived from the five hormone-secreting cell types, or to extrapituitary stimuli causing hypertrophy and hyperplasia of those cells. Various tumour-like conditions can mimic functioning adenomas. Rarely, no lesion is detected and intrinsic abnormalities of adenohypophyseal cells are implicated. Hypopituitarism can be selective or generalized. Diffuse hormone deficiency is usually attributable to tissue destruction by tumours, inflammatory or infiltrative conditions or vascular lesions. Congenital abnormalities of pituitary development may result in hypophyseal dysfunction. Hypothalamic abnormalities may cause generalized hypopituitarism or may involve only selective releasing factors and hormones. Feedback inhibition and receptor abnormalities may be implicated in pituitary hypofunction, and selective deficiencies may be the result of genetic abnormalities, immune reactions or toxic damage to one cell type.