Primary pigmented nodular adrenocortical disease: paradoxical responses of cortisol secretion to dexamethasone occur in vitro and are associated with increased expression of the glucocorticoid receptor

Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of ACTH-independent adrenal Cushing's syndrome (CS), which is often associated with Carney complex (CNC). We have recently described a paradoxical increase in cortisol excretion after dexamethasone administration in most patients with PPNAD. In the present study we investigated the hypothesis that this phenomenon is due to a primary abnormality of the tissues affected by PPNAD, rather than a defect of the patients' hypothalamic-pituitary-adrenal axis; as such it should be replicated in vitro by adrenal slices exposed directly to dexamethasone. We were able to study adrenal tissues from eight patients with CS caused by PPNAD; two patients were also studied in vivo according to a protocol first described in ACTH-independent macronodular adrenal hyperplasia (AIMAH) for the clinical detection of aberrant hormone receptor expression. Their DNA has been previously screened for inactivating mutations of the PRKAR1A gene, the most frequent molecular defect leading to PPNAD and/or CNC. We also investigated whether glucocorticoid receptor (GR) expression underlies paradoxical dexamethasone responses in PPNAD by immunohistochemistry and semiquantitative PCR, and we correlated GR expression with that of other markers for PPNAD (e.g. synaptophysin). Indeed, we demonstrated that dexamethasone induced cortisol secretion in vitro in five of these tumors; no such increase was seen in adenomatous or AIMAH tissues that were treated in the same manner. GR mRNA was expressed, and GR immunoreactivity was detected in PPNAD nodular cells. Staining for GR was not seen in surrounding cortical cells, and hence, it correlated with synaptophysin, which also stains PPNAD in a similar manner. In normal adrenal tissue, GR was detected mostly in medullary areas, whereas GR immunoreactivity was weak in adenomatous and AIMAH tissues. We conclude that 1) dexamethasone produces an increase in glucocorticoid synthesis by PPNAD adrenal slices in vitro, suggesting a direct effect on adrenocortical tissue, and 2) this phenomenon is accompanied by increased expression of the GR in PPNAD nodules. PPNAD and/or CNC patients with and without mutations leading to protein kinase A activation demonstrated in vitro and/or in vivo paradoxical dexamethasone responses and GR expression, indicating that PRKAR1A alterations are not necessary for these phenomena.

The role of calretinin, inhibin, melan-A, BCL-2, and C-kit in differentiating adrenal cortical and medullary tumors: an immunohistochemical study

Morphologic distinction between adrenal cortical and medullary tumors can be difficult. Previous studies have shown inhibin, melan-A, and BCL-2 to be useful markers for adrenal cortical tumors. We have recently observed a high level of calretinin expression in normal adrenal cortex but not the medulla and therefore evaluated its diagnostic application for adrenal tumors in comparison with inhibin, melan-A, and BCL-2. C-kit is a transmembrane tyrosine kinase receptor. Immunodetection of c-kit expression has been recently used for tumor diagnosis, and c-kit-positive tumors can potentially benefit from kit kinase inhibitor treatment. Although c-kit expression was reported in adrenal medulla and pheochromocytoma, it has not been evaluated in adrenal cortical tumors. In this study, 28 adrenal cortical tumors (12 carcinomas, 16 adenomas), 20 pheochromocytomas, and 20 extraadrenal paragangliomas were evaluated for calretinin, inhibin, melan-A, BCL-2, and c-kit expression by standard immunohistochemical assays on paraffin sections. The percentage of immunoreactivity in adrenal cortical tumors was as follows: calretinin, 96%; melan-A, 89%; inhibin, 92%; BCL-2, 20%; and c-kit, 5%. Normal adrenal medulla did not stain for c-kit but was positive for BCL-2. Eighty-six percent of pheochromocytomas stained for BCL-2 and none for calretinin, with the exception of the ganglioneuromatous areas in composite pheochromocytomas (n = 5). Extraadrenal paragangliomas showed reactivity with calretinin in 25%, melan-A in 5%, inhibin in 16%, BCL-2 in 38%, and c-kit in 8% of the cases. Our results indicate that calretinin is the most sensitive among all the adrenal markers tested. Like melan-A and inhibin, calretinin is also a very specific marker in differentiating cortical from medullary adrenal tumors. In addition, calretinin can be used to confirm a composite pheochromocytoma. BCL-2 does not appear to be useful in differentiating adrenal cortical from medullary tumors. C-kit is not useful in the diagnosis of adrenal tumors, and kit kinase inhibitor might have a limited role in the treatment of adrenal tumors and paraganglioma because of the low frequency of c-kit expression in these tumors.

[Tumors of the adrenal medulla and the paraganglia]

The sympathetic and parasympathetic paraganglia are the site of pheochromocytomas and paragangliomas. The adrenal pheochromocytoma and the abdominal paraganglioma derive from the sympathetic nervous system. The parasympathetic paragangliomas are predominantly localized in the head and neck region. Most pheochromocytomas are hormonally active and benign. The abdominal paragangliomas usually correspond to adrenal pheochromocytomas, but are more commonly malignant. The parasympathetic paragangliomas are usually benign, hormonally inactive and are most commonly located in the bifurcation of the carotid artery.

TSPY-LTA transgenic mice develop endocrine tumors of the pituitary and adrenal gland

In an attempt to determine the susceptibility of spermatogonia to malignant transformation transgenic mice were generated harboring a 1.3 kb 5'-flanking region of the germ cell specific expressed human testis specific protein, Y-encoded gene fused with the simian virus 40 large T antigen (TAg). Unexpectedly, TAg expression in transgenic mice was also detected in somatic tissues. Between days 65 and 85 after birth most of the transgenic mice developed anterior lobe tumors of the pituitary gland and to a less extent medulla type tumors of the adrenal gland. In addition, a few older transgenic mice developed tumors of the seminal vesicle, but no testicular tumors were observed in transgenic mice up to an age of 5 months. The pituitary tumors were immunoreactive for anti-prolactin (PRL) and anti-adrenocorticotropic hormone (ACTH). PRL and corticosterone concentrations in serum of transgenic mice were significantly increased. Taken together, our studies provide a novel mouse model for pituitary adenomas displaying a unique combination of hormone expression by tumor cells secreting PRL and ACTH.

Ret protein expression in adrenal medullary hyperplasia and pheochromocytoma

Ret is a developmentally regulated tyrosine kinase involved in formation and maintenance of the nervous system. Ret mutations predisposing to pheochromocytomas and medullary thyroid carcinomas occur in multiple endocrine neoplasia (MEN) syndromes 2A and 2B. Biochemical studies have demonstrated overexpression of Ret mRNA and protein in pheochromocytomas compared to normal adrenal medulla. However, the cellular distribution of Ret in the normal human adrenal and in hyperplastic lesions that antecede pheochromocytomas are unclear. The present investigation was undertaken to resolve the histological distribution of Ret in the normal human adrenal, in pheochromocytomas evolving from adrenal medullary hyperplasia in MEN2A and in sporadic pheochromocytomas. Ret expression was studied by immunohistochemistry using both a polyclonal and a monoclonal antibody, with confirmation by immunoblotting of representative cases. Only occasional cells stained for Ret in the normal adrenal, consistent with the distribution in adult adrenals of other species. Heterogeneous, progressively increased Ret expression was observed during the evolution of pheochromocytomas. In both normal and neoplastic adrenal, the most intense immunoreactivity was observed in cells with neuron-like features. Our finding that Ret is not expressed at high levels in the early stages of disease suggests that elucidation of mechanisms that regulate Ret expression is required for understanding the pathobiology of MEN2A. The association of high-level Ret expression with neuronal morphology suggests that the variable overexpression of Ret in pheochromocytomas might in part be an epiphenomenon, reflecting the known phenotypic plasticity of these tumors.

[Morphological and morphometrical changes in nervous apparatus of the adrenal medulla after sudden death of patients with various cardiac pathology]

Adrenal glands were studied at early autopsy of 28 men aged 35-60 years after their sudden cardiac death. According to the presence and character of pathologic manifestations detected in myocardium, three groups of cases were distinguished: group 1 (control) included the people without myocardial pathology (traffic accident victims), group 2 consisted of the patients with ischemic heart disease (IHD) in association with recent myocardial infarction, group 3 included the patients with IHD and hypertension. The study was performed using the methods of silver impregnation of nerve terminals and planimetric point-counting method. Analysis of density of distribution of nerve plexuses in adrenal medulla in the groups studied has shown a tendency towards its reduction in group 2 and a significant decrease in group 3. Reactive-degenerative changes in the nervous structures of adrenal medulla were detected in these two groups, while in group 3 these were accompanied by the compensatory-adaptive changes in glandular nervous apparatus. However, despite the pronounced changes found in the nervous structures of adrenal medulla, their function remained high enough, that could be explained by a transition from nervous control of adrenal activity to a humoral one.

[Misdiagnosis of corticomedullary mixed pathological changes in adrenals: report of 4 cases]

Pathological changes usually occur independently in the adrenal cortex and medulla because of their distinct embryonic origins, and changes involving both the cortex and medulla are rare. We report 4 cases of corticomedullary mixed pathological changes adrenal glands. CT scanning of the adrenal glands showed unilateral abnormalities in all the 4 cases, 3 of which were diagnosed as aldosteronism and the other pheochromocytoma before surgery. Unilateral adrenalectomy was performed in the 4 patients 3 being cured and discharged. The other 1 had recurrence 18 months postoperatively with suspected pathological changes on the other side. Subsequent pathological examination confirmed the suspicion in both the cortex and medulla of the other adrenal gland. In cases with clinical presentations as simultaneous onset of aldosteronism and catecholamine responses, pathological changes in both the cortex and medulla of the adrenal glands should be considered. Perioperative management of such cases should be the same as that in cases of catecholamine responses, and the diagnosis relies on histopathological examination.

Increased expression of adenylyl cyclase isoforms in the adrenal gland of diabetic Goto-Kakizaki rat

The spontaneously diabetic Goto-Kakizaki rat harbors the same defects expressed in human type 2 diabetes. It is not clear, however, whether stress factors emanating from the adrenal glands are involved in causing the diabetic state. For that reason, the authors studied gland size and expression of adenylyl cyclase isoforms in adrenal glands from Goto-Kakizaki and normal rats. Goto-Kakizaki rat adrenals were found to weigh only about half as much as those of control rats. This decrease was the result of a reduction of the cortex, especially of the zona fasciculata, whereas the medulla was unaffected. Cell density measurements showed that the total number of medullary cells in Goto-Kakizaki rats was lower than that in controls. In the cortex, the cell density did not differ between the two groups; thus, our results point to a marked hypotrophy. In the medulla of Goto-Kakizaki rats, the nuclear size was significantly increased, and there was also an overexpression of adenylyl cyclase 1, 2, 4, 6, and 8 isoforms in the adrenalin-producing cells, indicating an increased functional capacity. In the cortex, despite the cortical hypotrophy, adenylyl cyclase 5 immunoreactivity was markedly increased in Goto-Kakizaki rats, especially in the zona reticularis. It is unclear whether this morphologic change in the diabetic adrenal glands together with the overexpression of different adenylyl cyclase isoforms plays a role in the pathogenesis of this diabetic state or is a genetic defect or compensatory mechanism of diabetes in this spontaneous rodent model of type 2 diabetes.

Development of chromaffin cells depends on MASH1 function

The sympathoadrenal (SA) cell lineage is a derivative of the neural crest (NC), which gives rise to sympathetic neurons and neuroendocrine chromaffin cells. Signals that are important for specification of these two types of cells are largely unknown. MASH1 plays an important role for neuronal as well as catecholaminergic differentiation. Mash1 knockout mice display severe deficits in sympathetic ganglia, yet their adrenal medulla has been reported to be largely normal suggesting that MASH1 is essential for neuronal but not for neuroendocrine differentiation. We show now that MASH1 function is necessary for the development of the vast majority of chromaffin cells. Most adrenal medullary cells in Mash1–/– mice identified by Phox2b immunoreactivity, lack the catecholaminergic marker tyrosine hydroxylase. Mash1 mutant and wild-type mice have almost identical numbers of Phox2b-positive cells in their adrenal glands at embryonic day (E) 13.5; however, only one-third of the Phox2b-positive adrenal cell population seen in Mash1+/+ mice is maintained in Mash1–/– mice at birth. Similar to Phox2b, cells expressing Phox2a and Hand2 (dHand) clearly outnumber TH-positive cells. Most cells in the adrenal medulla of Mash1–/– mice do not contain chromaffin granules, display a very immature, neuroblast-like phenotype, and, unlike wild-type adrenal chromaffin cells, show prolonged expression of neurofilament and Ret comparable with that observed in wild-type sympathetic ganglia. However, few chromaffin cells in Mash1–/– mice become PNMT positive and downregulate neurofilament and Ret expression. Together, these findings suggest that the development of chomaffin cells does depend on MASH1 function not only for catecholaminergic differentiation but also for general chromaffin cell differentiation.

[Diagnosis and treatment of adrenal medullary hyperplasia (with report of 8 cases)]

OBJECTIVE

To study the diagnosis and treatment of adrenal medullary hyperplasia (AMH).

METHODS

An retrospective analysis of the clinical data of 8 patients with AMH admitted in our hospital from May 1998 to May 2002 were conducted with a review of the follow-up study.

RESULTS

CT scanning of the adrenal gland showed unilateral abnormal appearance in all 8 cases. Diagnoses of AMH in 4 patients and pheochromocytoma in the other 4 patients were established before surgery. All the patients underwent unilateral adrenalectomy, among whom 7 were cured and 1 suffered recurrence 1 month after operation because of medullar hyperplasia in the contralateral adrenal gland.

CONCLUSIONS

AMH should be differentiated from pheochromocytoma, especially from adrenal nodules shown by catecholamin assay. Definite diagnosis depends on pathological examination and surgical removal through abdominal approach is the best choice of treatment, in which both sides of the adrenal glands should be explored.

Ultrastructural criteria of malignancy of adrenal medullary tumor

Histological analysis and electron microscopy of 12 benign pheochromocytomas and 9 malignant pheochromoblastomas showed that there are no reliable histological differences between cells of benign and malignant tumor of the adrenal medulla. The ratio of ultrastructurally differentiated and undifferentiated cells in the tumor can reflect their maturity; the more ultrastructurally undifferentiated and less differentiated cells in the tumor, the higher is the malignant potential of this tumor.

Synchronous laparoscopic-assisted right hemicolectomy and right adrenalectomy

In recent years, minimally invasive surgery has been increasingly employed for the treatment of colorectal and adrenal tumors. We report an 82-year-old woman with synchronous right-sided colonic tumor and right adrenal tumor requiring resection. Preoperative workup showed a 6-cm primary right adrenal tumor with no evidence of invasion to adjacent structures. Laparoscopic removal of the two tumors was achieved with the use of a hand-port device, which assured safe retraction of the liver and meticulous dissection of the adrenal tumor, as well as port site protection during retrieval of the specimens. The whole operation lasted 270 min and our patient made an uneventful recovery.

Myelolipoma associated with adrenal ganglioneuroma

Adrenal myelolipomas are rare, benign mesenchymal tumors composed of mature adipose tissue and hematopoietic cells in varying proportions. Although the majority of cases occur as isolated adrenal lesions, myelolipomas have been described in association with various adrenal pathologic conditions. These conditions include enzyme deficiencies and hyperplastic and neoplastic lesions of the adrenal cortex, with perhaps endocrine dysfunction as a common feature. Ganglioneuroma is a benign tumor of the sympathetic nervous system that rarely produces symptoms of endocrine dysfunction. We report an unusual case of myelolipoma associated with ganglioneuroma of the adrenal medulla. The histogenesis of myelolipoma remains speculative. However, the close proximity to adrenal cortical cells within the stroma of ganglioneuroma suggests that the hormonal microenvironment may have played a role in the development of the myelolipoma.

Recovery of injured adrenal medulla by differentiation of pre-existing undifferentiated chromaffin cells

We described previous that the adrenal medulla recovers rapidly from the injuries due to salinomycin. In the present study we found the recovery to be apparently due to differentiation of pre-existing, primitive undifferentiated, chromaffin cells, rather than mitosis, as evidenced by lack of incorporation of 5-bromo-2-deoxyuridine in the differentiating and/or differentiated chromaffin cells. Electron-dense, striated fibrils observed within the necrotic cells and in the extracellular space were presumed to be intermediate degradation products. Schwann cells actively functioned as phagocytes in this study, and seemed to indirectly stimulate the differentiation of undifferentiated chromaffin cells.

Undifferentiated ganglioneuroblastoma in a sheep

Ganglioneuroblastoma, presumably originating from the adrenal medulla, was found in an 18-month-old sheep. Histologically, the tumour was mainly composed of undifferentiated neuroblasts with neuropil and occasional ganglion cells. The morphological and immunohistochemical features with respect to intermediate filament proteins and the neuroendocrine nature of the tumour are described. The neoplastic cells were positive for neuron-specific enolase, synaptophysin and vimentin.

Growth factors and cytokines in paragangliomas and pheochromocytomas, with special reference to sustentacular cells

The aim of this study was to localize various growth factors and cytokines in paragangliomas and pheochromocytomas in order to understand their possible autocrine or paracrine functions, and to compare sustentacular cells of the adrenal medulla with pituitary stellate cells. Thirteen resected tumors, 11 paragangliomas and 2 pheochromocytomas of the adrenal medulla, were studied. In addition, five surgically removed nontumorous adrenals and five nontumorous pituitaries were studied. Varying numbers of sustentacular cells were immunopositive for S-100 protein and in most instances for glial fibrillary acidic protein. Insulin-like growth factor-1 (IGF-1), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 were localized to both cell types in all cases, whereas epidermal growth factor (EGF) immunopositivity was noted in only three. In all tumors, leukemia inhibitory factor (LIF) was restricted to chief cells and EGF receptor to sustentacular cells. Nontumorous chief cells and sustentacular cells of adrenal medulla exhibited immunoreactivities similar to those of paragangliomas and pheochromocytomas. Secretory adenohypophysial cells displayed various immunoreactivities for all growth factors, receptors, and cytokines studied. Pituitary stellate cells were immunopositive for EGF, EGF receptor, IGF-1, LIF, and TNF-alpha. In conclusion, paragangliomas and pheochromocytomas are immunoreactive for a wide spectrum of growth factors and cytokines. Immunocytochemistry demonstrated similarities between sustentacular cells and stellate cells of the pituitary in addition to their similar morphology. The significance of these observations regarding paracrine activities of chief and sustentacular cells remains to be determined.

Adrenal cortical and medullar hyperplasia--a retrospective analysis of 6 cases

The features of the symptoms, laboratory tests and pathological characteristics of adrenal cortical and medullary hyperplasia were studied. In 6 cases of hypercatecholaminenia, plasma norepinephrine (NE), epinephrine (E), catecholamine (CA) and 24-h urinary vanillylmandelic acid (VMA), 17-hydroxycorticosteroid (OHCS) and 17-ketosteroid (KS) were determined. Adrenal glands were examined by CT scan and 131I-MIBG imaging. Pathological examination was performed after operation. The results showed that in 6 cases of hypercatecholaminenia (3 men and 3 women) aged from 34-50 years, the clinical features were just like "pheochromocytoma", for example, episodic headache, perspiration, palpitation, pallor, apprehension, nausea, tremor, anxiety and so on. Plasma levels of CA, NE and E were elevated in all 6 cases. 24-h urinary samples obtained at the onset revealed elevated VMA in 1 case. 24-h urinary cortisol was obviously elevated in all 6 cases. 24-h urinary 17-OHCS, 17-KS was normal. B-type ultrasound, CT, MRI and 131I-MIBG revealed 9 lateral adrenal gland diffuse or nodular enlargement in 6 cases. Pathologic examination showed adrenal cortical and medullary hyperplasia. Clinically, adrenal cortical and medullary hyperplasia resembled "pheochromocytoma". The most significant feature of this disease was both elevated plasma CA and 24-h urinary cortisol obviously. Pathologic examination showed adrenal cortex nodular hyperplasia and medullar diffuse or limit hyperplasia. Whether it is an independent disease or symptoms of the other disease has not final conclusion up till now.

Induction of orthotopic rat adrenomedullary neoplasia by intraadrenal pheochromocytoma cell transplantation

We aimed to establish a technically feasible, easily reproducible model of orthotopic adrenomedullary neoplasia. Male rats received adrenal injection of rat pheochromocytoma cells infected with the Escherichia coli gene for beta-galactosidase (lac Z). Each of 10 animals was perfused 7 or 24 days after tumor cell injection; 5 animals of each group were injected with cyclosporin. Animals without tumor cell injection served as controls. Tumor cells were identified and characterized in frozen sections by histochemical and immunohistochemical methods. Immunosuppressed animals had enlarged adrenals 7 days after tumor cell injection. In the rats without immunosuppression the adrenals seemed unaltered despite microscopic demonstration of tumor cells. After 24 days tumors had developed in all animals, weighing 50 times more than normal adrenals in animals with immunosuppression, and 9 times more in animals without immunosuppression. Intraadrenal catecholaminergic tumor cells could be identified by beta-galactosidase expression. No animal showed systemic spread. Generation of adrenomedullary neoplasia by intraadrenal pheochromocytoma cell transplantation is easily reproducible and technically feasible. This model allows simultaneous study of neoplastic and normal adrenal tissues (e.g., regarding their response to drugs intended for diagnostic and therapeutic purposes). The decreased tumor growth in animals without immunosuppression is presumably due to the high number of intraadrenal immunocompetent cells.

Primitive small round cell tumour of the adrenal gland presenting with fever of unknown origin and t(12;22)(q13;q12) cytogenetic finding

This report describes a left adrenal tumour in a 16 year old Chinese girl who presented with fever of unknown origin. The histological and ultrastructural features of the adrenal tumour were those of a primitive small round cell tumour with neuroendocrine differentiation. Cytogenetic analysis of cultured tumour cells showed a reciprocal translocation t(12;22)(q13;q12). This is the first example of such a tumour being reported in the adrenal gland. The adrenal tumour was also the cause of the fever, which subsided after the removal of the tumour.

A new splicing variant for human tyrosine hydroxylase in the adrenal medulla

It has been reported that several mRNA isoforms of tyrosine 3-monooxygenase (tyrosine hydroxylase; TH) occur only in primates. New TH isoforms produced by skipping of exon 3 in the adrenal medulla of patients with progressive supranuclear palsy (PSP) have recently been reported, J. Neurochem. 67 (1996) 19. Here, we looked for the presence of new TH isoforms in control brains and adrenal medulla and in brains from patients with PSP. We found a novel type of TH mRNA in the adrenal medulla from one of the control subjects. The mRNA lacked exon 4, resulting in a premature stop codon at amino acid 147. This result suggests the importance of alternative splicing in the regulation of TH activity.

Corticomedullary mixed tumor of the adrenal gland

Corticomedullary mixed tumors of the adrenal gland are quite rare, with only five well-documented cases reported in the literature.(1-4) Herein, we report the light microscopic and immunohistochemical features of two cases of this rare tumor. Patient 1 is a 34-year-old woman who presented with hypertension, hair loss, and amenorrhea of 1-year duration. Patient 2 is a 52-year-old woman who presented with flank pain and what appeared to be a renal mass on arteriogram with no history of hypertension, Cushing's syndrome, or other endocrine abnormalities. At surgery, the tumor was noted to arise from the adrenal gland rather than the kidney and adrenalectomy was performed. In both cases, the surgically resected specimens consisted of a well-circumscribed, single adrenal mass surrounded by a rim of uninvolved adrenal cortical tissue. The tumors were composed of adrenal cortical cells intimately admixed with pheochromocytes. Immunohistochemical studies highlighted these two cellular components. The pheochromocytes were strongly reactive with chromogranin and the sustentacular cells with S-100 protein, whereas the adrenal cortical cells reacted specifically with inhibin. Thus, we report two additional cases of mixed corticomedullary tumor of the adrenal gland. Ann Diagn Pathol 5:304-308, 2001. This is a US government work. There are no restrictions on its use.

[Transposition of pedicled adrenal gland for the treatment of adrenal medullary hyperplasia]

OBJECTIVE

To investigate the operative modes for adrenal medullary hyperplasia.

METHODS

8 cases of adrenal medullary hyperplasia were treated with transposition of pedicled adrenal gland. The inferior and the medial blood vessel of adrenal gland were ligated. The superior blood vessel of adrenal gland was formed a 5.0- 6.0 cm pedicle and dragged to the subcutaneous of dorsum.

RESULT

After follow-up for an average of 2 years, only 1 of the 8 patients did not recover as a result of psychosis and others had no symptoms but normal endocrine results.

CONCLUSION

Transposition of the pedicled adrenal gland is a simple and satisfied way to treat patients with adrenal medullary hyperplasia.

Basic and clinical aspects of intraadrenal regulation of steroidogenesis

The adrenal gland combines essential components of the autonomic nervous system and the HPA axis in close contact. From morphological analyses employing immunohistochemistry, in situ hybridization, the novel technique of laser capture microdissection, and electron microscopy, it has been has shown that the chromaffin cells of the adrenal medulla and the steroid-producing cells of the adrenal cortex are extensively intermingled and functionally interrelated. In in vitro studies, a variety of regulatory factors produced and released by the adrenal medulla were identified as playing an important role in modulating adrenocortical function. An isolated adrenocortical cell deprived of its tissue integrity, input from the nervous system, or intercellular communication with chromaffin, vascular, and immune cells of the adrenal gland, loses its normal capacity to produce glucocorticoids and to adequately respond to the homeostatic challenges of stress. Adrenocortical cells in co-culture with chromaffin cells produced ten times more glucocorticoids than the same number of pure adrenocortical cells and demonstrated marked up-regulation in the mRNA expression of cytochrome p450 enzymes and STAR in the co-culture, while this expression was down-regulated in isolated cells. Transgenic animal models of over-expression or deletion of enzymes involved in catecholamine synthesis, as well as of altered function of components of the HPA axis, provide evidence that the mutual interdependence of the sympatho-adrenal system and the HPA axis at the level of the adrenal gland is of physiologic relevance in vivo. Alterations in intercellular communications, local production of neuropeptides, growth factors and cytokines, and aberrant expression of ectopic receptors on adrenal cells have been implicated in adrenal cell growth, development, hyperplasia, tumor formation, autonomous hormone production, and autoimmune disease. Moreover, we described a direct cellular interaction of lymphocytes with adrenal cells as a novel non-cytokine mediated mechanism of immune endocrine interactions. Highlighting the importance of the extra-pituitary mechanisms of adrenocortical regulation, be them neural or immune, is a worthwhile starting point for a more complete analysis of the human stress system in vivo.

Intermittent hyperaldosteronism in a child due to an adrenal adenoma

Aldosterone producing adenoma (APA) is a rare but potentially curable form of paediatric hypertension. We report a case of APA in a 9-year-old boy, suspected due to persistent hypokalaemia. Neither BP nor initial laboratory investigations disclosed the diagnosis and the presence of an APA was suggested by functional tests and radiological findings. Histologically, a cortical tumour was found associated with a marked medullary hyperplasia of both chromaffin and ganglion cells.

CONCLUSION

This case reinforces the need for further investigations in patients with misleading clinical and laboratory data.