Paraganglia of the Gallbladder: An Underrecognized Incidental Finding and Potential Diagnostic Pitfall.

CONTEXT.­: The identification of paraganglia (PG) in the gallbladder (GB) is infrequent, and easily overlooked as it is not something routinely reported. Occasionally they may be misinterpreted as neoplastic cells, such as low-grade carcinomas, germ cell tumors, or because of their close resemblance to neuroendocrine cells, as low-grade neuroendocrine neoplasms. OBJECTIVE.­: To evaluate the incidence and histological features of PG of the GB in patients that underwent cholecystectomy, and discuss the potential misinterpretation of these benign structures as clusters of neoplastic cells. DESIGN.­: A retrospective study of cholecystectomy specimens performed during a 6-month period were reviewed for identification of PG. Immunohistochemical studies for chromogranin, synaptophysin, S100, and cytokeratin AE1/AE3 were performed in selected cases. RESULTS.­: A total of 365 GBs were reviewed and in 16 cases (4.4%) PG was identified within the subserosal connective tissue of the GB wall or cystic duct adjacent to small capillaries, nerves, and ganglia. They consisted of well-demarcated, lobular structures ranging in size from 0.2 to 0.5 cm, which were predominantly composed of chief cells, with strong expression for chromogranin and synaptophysin and negative CKAE1/AE3, and a minor component of S100-positive sustentacular cells. CONCLUSIONS.­: PG is an uncommon finding with a prevalence of 4.4% in our study. Awareness of their location, histologic features, and immunohistochemical profile may help practicing pathologists to confirm their benign nature, avoid a misdiagnosis of malignancy, and prevent unnecessary diagnostic work-up and treatment.

Metabolomics Analyses of 14 Classical Neurotransmitters by GC-TOF with LC-MS Illustrates Secretion of 9 Cell-Cell Signaling Molecules from Sympathoadrenal Chromaffin Cells in the Presence of Lithium.

The classical small molecule neurotransmitters are essential for cell-cell signaling in the nervous system for regulation of behaviors and physiological functions. Metabolomics approaches are ideal for quantitative analyses of neurotransmitter profiles but have not yet been achieved for the repertoire of 14 classical neurotransmitters. Therefore, this study developed targeted metabolomics analyses by full scan gas chromatography/time-of-flight mass spectrometry (GC-TOF) and hydrophilic interaction chromatography-QTRAP mass spectrometry (HILIC-MS/MS) operated in positive ionization mode for identification and quantitation of 14 neurotransmitters consisting of acetylcholine, adenosine, anandamide, aspartate, dopamine, epinephrine, GABA, glutamate, glycine, histamine, melatonin, norepinephrine, serine, and serotonin. GC-TOF represents a new metabolomics method for neurotransmitter analyses. Sensitive measurements of 11 neurotransmitters were achieved by GC-TOF, and three neurotransmitters were analyzed by LC-MS/MS (acetylcholine, anandamide, and melatonin). The limits of detection (LOD) and limits of quantitation (LOQ) were assessed for linearity for GC-TOF and LC-MS/MS protocols. In neurotransmitter-containing dense core secretory vesicles of adrenal medulla, known as chromaffin granules (CG), metabolomics measured the concentrations of 9 neurotransmitters consisting of the catecholamines dopamine, norepinephrine, and epinephrine, combined with glutamate, serotonin, adenosine, aspartate, glycine, and serine. The CG neurotransmitters were constitutively secreted from sympathoadrenal chromaffin cells in culture. Nicotine- and KCl-stimulated release of the catecholamines and adenosine. Lithium, a drug used for the treatment of bipolar disorder, decreased the constitutive secretion of dopamine and norepinephrine and decreased nicotine-stimulated secretion of epinephrine. Lithium had no effect on other secreted neurotransmitters. Overall, the newly developed GC-TOF with LC-MS/MS metabolomics methods for analyses of 14 neurotransmitters will benefit investigations of neurotransmitter regulation in biological systems and in human disease conditions related to drug treatments.

Paraganglia of the gallbladder: a report of two cases with an immunohistochemical study.

Paraganglionic tissues incidentally observed in the gallbladder are presented. The patients, a 51- and a 55-year-old woman, underwent gallbladder resection for chronic cholecystitis with gallstones. Two and one paraganglionic tissues were observed in the subserosal connective tissue of the two gallbladders, respectively. Immunohistochemically, the chief cells were positive for chromogranin A, and the sustentacular cells were positive for S100 protein. Tyrosine hydroxylase (in two of three), dopamine beta-hydroxylase (in one of three), methionine-enkephalin (in two of three), and leucine-enkephalin (in two of three) were also positive in a small amount of the chief cells. These structures, which slightly resembled adrenal medulla or retroperitoneal paraganglia, might be misunderstood as an infiltration of primary or metastatic carcinoma into the subserosal connective tissue.

Paraganglia of the prostate. Location, frequency, and differentiation from prostatic adenocarcinoma.

In contrast to paraganglia of the urinary bladder, prostatic paraganglia have been largely unreported. Following the discovery of paraganglia in two separate radical prostatectomy specimens, we reviewed 100 randomly selected radical prostatectomy specimens to document the location and frequency of prostatic paraganglia. Twelve additional paraganglia were identified in eight resections, for a total of 14 paraganglia in 10 cases. Most paraganglia were located in or adjacent to lateral neurovascular bundles and, rarely, in lateral prostatic stroma. The size of paraganglia ranged from 0.1 to 1.7 mm (median 0.9 mm). Paraganglia consisted of clusters of cells in patterns that ranged from lobular to diffuse, usually with a prominent stromal vascular component. The cells contained bland oval nuclei and clear cytoplasm, which was often abundant. Occasionally, larger cells with larger nuclei were present. Immunohistochemical stains for chromogranin, neuron-specific enolase, and synaptophysin were positive; those for prostatic-specific antigen were uniformly negative. In one of our cases, histologic similarity was noted between a paraganglion and an adjacent prostatic adenocarcinoma with a "hypernephroid" pattern. Recognition of prostatic paraganglia, with appropriate immunohistochemical stains when necessary, will obviate the possibility of confusing these structures with prostatic adenocarcinoma.

Perinatal development of galanin-like immunoreactivity in chromaffin tissues of the rabbit.

We have analyzed the perinatal development of galanin-like immunoreactivity (GAL-LI) and catecholamines (CA) in the paraaortal paraganglia (PGGL) and adrenal glands. In the PGGL, the tissue content of GAL-LI was highest on the day of birth and decreased postnatally. The fetal levels were lower than at birth. In contrast, the content of CA in the PGGL increased with age. In the adrenal glands, the contents of both GAL-LI and CA also increased with age. During the first postnatal week the contents of both GAL-LI and CA in the PGGL were markedly higher than in the adrenal glands. Chromatographic analysis of GAL-LI in extracts of fetal and postnatal rabbit PGGL, respectively, indicated that most of the GAL-LI from both age groups co-eluted with synthetic porcine GAL. An additional, apparently more polar, component was also detected at both ages, which may represent a differently processed form of the peptide. The high content of GAL-LI in the PGGL at birth may reflect an enhanced synthesis associated with birth.

An immunohistochemical study of human postnatal paraganglia associated with the urinary bladder.

Histological and immunohistochemical methods were used to study pelvic paraganglia in a series of human postnatal specimens ranging in age from 1 month to 6 y. Up to 5 months of age, many of the encapsulated paraganglia contained small pacinian-like sensory corpuscles which occurred either singly or in small clusters, implying an unknown functional interrelationship during this period. In older specimens, this intimate association was not observed since pacinian corpuscles and small nonencapsulated clusters of paraganglion cells were observed only as separate structures. It is suggested that the paraganglion cells may induce the formation of the pacinian corpuscles during fetal development. Immunohistochemistry using the nerve marker protein gene product (PGP 9.5) demonstrated a rich plexus of varicose nerve fibres within the paraganglia which may directly innervate the paraganglion cells and/or be associated with the profuse vascular supply. A similar density of vasoactive intestinal polypeptide-containing nerves was also demonstrated while some of the nerves contained calcitonin gene related peptide or substance P. The paraganglion cells stained positively for tyrosine hydroxylase, dopamine-beta-hydroxylase and neuropeptide Y, but not for phenylethanolamine N-methyltransferase. This combination of immunostaining confirms them as a rich source of noradrenaline.

Enkephalin- and serotonin-like immunoreactivity in the aortico-pulmonary paraganglia of the white-belly opossum Didelphis albiventris (Marsupialia).

Serial histological sections of the interatrial septum and basal heart vessels of the weaned and juvenile white-belly opossum (Didelphis albiventris) were obtained in order to study the presence of paraganglia and their content of regulatory peptides and serotonin. Paraganglion groups were mapped between the aorta and pulmonary arteries and close to the bifurcation of the pulmonary trunk and were found to contain cells with immunoreactivity to serotonin and to the neuroendocrine markers PGP 9.5 and NSE. When these paraganglia were tested for immunoreactivity to a battery of regulatory peptides, all were found to be positive for methionine-enkephalin, leucine-enkephalin and galanin. The hypothesis is raised that these peptides and serotonin, besides catecholamines, produced by these paraganglia may play a physiological role in the functions of the cardiovascular system of the white-belly opossum.

Immunocytochemical identification of neuroendocrine markers in human cardiac paraganglion-like structures.

Paraganglion-like structures (PLS) containing chromaffin-positive cells have been reported to be present in the adult human heart. The present work was initiated in order to evaluate the density of these structures in the interatrial septum and to study the presence of immunoreactivity of their cells to NSE and PGP 9,5 antibodies, two neuroendocrine markers. Six hundred 6-microns paraffin serial sections were obtained from the upper third of the interatrial septum from six adult human hearts. From 2 to 12 paraganglia were found in each case, and their principal cells stained positively with NSE and PGP 9,5 antibodies. Depending on how these PLS related to other cardiac structures, four different types were identified: Type I - "True paraganglia" (located adjacent to ganglia or nerve fibers); Type II - "Free paraganglia" (immersed in the interatrial adipose tissue, without evident connection to other structures); Type III - "Intraganglionic paraganglia" (located within the nervous ganglia); Type IV - "Intramyocardic paraganglia" (small nests of immunoreactive cells closely related to myocardiocyte bundles). These cardiac paraganglia, which probably belong to the visceral-autonomic group, may have a role in the regulation of the cardiac function and in the adaptive mechanisms of the heart. Its is also possible that they originate functioning and non-functioning tumours.