Melanotic progonoma of temporal and occipital bones: A case report.

Melanotic progonoma is a rare tumor that primarily affects the maxilla of infants during the first year of life. Involvement in the skull is rare and can mimick other benign or malignant tumors affecting the infant's skull. The authors report a case of melanotic progonoma of right occipital and temporal bones in a 7-months' girl and discuss the histological features, immunohistochemistry study, differential diagnosis and management of this tumor.

[Role of the pathologist in the diagnosis of palpebral keratoacanthoma: case report and literature review]. / Rôle du pathologiste dans le diagnostic du kératoacanthome de la paupière : à travers un cas et une revue de la littérature.

We report the case of a keratoacanthoma of the lower lid in a 14-year-old girl posing diagnostic difficulty with differentiating the lesion from a verrucous squamous cell carcinoma on histologic examination of an incisional biopsy. It was only upon complete excision of the tumor that the diagnosis of keratoacanthoma could be made and that of malignancy ruled out. We discuss the clinical and histologic diagnostic criteria for keratoacanthoma and assert that wide biopsy is essential for adequate morphologic study to enable better therapeutic management.

[Cerebral atypical rhabdoid/teratoid tumor: report of two cases]. / La tumeur tératoïde rhabdoïde atypique cérébrale : à propos de deux cas.

The cerebral atypical rhabdoid/teratoid tumor constitutes one of the most aggressive tumors of children. Such tumors are equally characterized by a critically and speedly mortal development. The optimal management of such tumors remains unknown. The authors report two cases of cerebral atypical rhabdoid teratoid tumor in 8- and 10-year girls and discuss the histological features, immunochemistry study, prognosis and treatment of these rare tumors.

Epidemiology of pediatric primary tumors of the nervous system: a retrospective study of 633 cases from a single Moroccan institution.

BACKGROUND AND PURPOSE: There are several reports regarding the epidemiology of pediatric brain tumors. However, little is known about the profile of pediatric brain tumors in Africa especially in Morocco in particular. The authors report the results of epidemiological analysis of a retrospective review of childhood primary brain tumors in a single institution. METHODS: A retrospective review of all cases of primary brain from 1 month to 15 years diagnosed at the Department of Pathology of the Hospital of Specialities of Rabat between January 1991 and December 2009 was performed. RESULTS: Six hundred and thirty-three primary tumors of the central nervous system were reviewed with a mean of 33.31 cases per year. According to the gender, 55% of the tumors occurred in males and 45% in females. The mean age was 8.36 years. Of all the tumors, 47% were situated in the supratentorial compartment, 48% in the infratentorial compartment, and 5% in spinal cord. In the infratentorial compartment, 82% of tumors are located in the cerebellum, 15% in the fourth ventricle, 2% in the brain stem and 1% in the cerebellar pontine angle. In the supratentorial compartment, two third of the tumors were located in the cerebral hemispheres and the sellar region. Thus 39% of tumors are located in the cerebral hemispheres followed by the sellar/suprasellar region (30%), lateral and third ventricles (11%), pineal region (8%), meninges (5%), choroid plexus (4%), and optic chiasma/tracts (3%). The most common types of tumors diagnosed were pilocytic astrocytoma and medulloblastoma together accounting for nearly half of the cases (46%) (23.1% and 22.9% respectively), followed by craniopharyngiomas (9%), ependymomas grade II (6.5%), glioblastomas (6%), astrocytomas grade II (4.4%), ependymomas grade III (3.9%). The other tumors represent 22.6%. CONCLUSION: We think that our results reflect fairly well the incidence of tumors of the nervous system in children due to the fact that this study was performed through many years in a single institution with a homogeneous neuropathological approach.

Solitary plasmocytoma: ghost tumour?

Solitary plasmocytoma is a rare tumour that belongs to the myeloid dysplasia group. The authors present an unusual evolution of this pathology through a clinical case. A 42-year-old patient was diagnosed with solitary nasosinusal plasmocytoma following biopsy of the right nasal fossa process; several weeks after this the tumour spontaneously regressed. Extramedullar plasmocytoma is a myeloid dysplasia that seldom evolves into multiple myeloma. Spontaneous regression has been described for some malignancies, implying immunological factors, but not previously for extramedullary plasmocytoma.

[Solitary fibrous tumor of the orbit: report of two cases and review of literature]. / Tumeur fibreuse solitaire de l'orbite : à propos de deux cas avec revue de la littérature.

Solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm that most frequently arises in the pleura and uncommonly involves the orbit. There are 54 cases of SFT of the orbit available in the literature. The authors report tow cases of an orbital SFT and discuss the clinical, radiological, pathological features and differential diagnosis. Long-term follow-up of patients is necessary because SFT may recur many years after operation. Complete surgical resection is the most important prognosis factor of this tumor.

[Primitive aspergillosis of the posterior cerebral fossa in immunocompetent patient]. / Aspergillose primitive de la fosse cérébrale postérieure chez un patient immunocompétent.

Cerebral aspergillosis arises in the great majority of cases during an invasive aspergillosis with hematogene scattering from the lung hurts. The cerebral, not rare location is one of the worse criteria forecast during the invasive aspergillosis. We report the case of patient who was hospitalized in the neurosurgery department for syndrome of increased intracranial pressure, hemiparesis and cerebellar syndrome in febrile context. The radiological exploration objectified a collection of the posterior fossa. A stereotactic biopsy was performed. It collected fragments biopsy and pus. The pathological and microbiological analysis allowed the identification of Aspergillus fumigatus. The originality of this observation comes from the rare location in the posterior fossa of aspergillosis and because the patient is immunocompetent and no primary location is found. The patient presents however a viral hepatitis B of fortuitous discovery. He is put under treatment by amphotericin B. The evolution is marked by meningitis comment-diversion. Antibiotics are prescribed, and then the patient is operated for total ablation of the tumor. He dies following an osmolar coma associated with thrombopenia and a secondary renal insufficiency due to his treatment by the amphotericin B.

[A case of cystic craniofacial fibrous dysplasia]. / Un cas de dysplasie fibreuse kystique craniofaciale.

INTRODUCTION: Fibrous dysplasia is a benign, idiopathic, fibro-osseous disease. CLINICAL CASE: A 17-year-old girl had presented with left proptosis for the previous two years, associated to homolateral hemicranial pain. Clinical examination was normal except for non-reducible axile exophthalmia. Computed tomography and magnetic resonance imaging of the head revealed an extensive cystic tumor of the left fronto-ethmoido-sphenoidal region, with compression of the left frontal lobe and medial orbital wall. The radiological appearance suggested a mucocele but histological examination, after surgery, proved a fibrous dysplasia. DISCUSSION: Fibrous dysplasia with fronto-sphenoido-ethmoidal localization may be misdiagnosed as mucocele. Histology proves the diagnosis.

[Papillary adenocarcinoma on ectopic thyroid tissue]. / Adénocarcinome papillaire sur tissu thyroïdien ectopique.

OBJECTIVES: To report a case of papillary adenocarcinoma occurring on ectopic thyroid tissue in the hyoid bone region. MATERIAL AND METHODS: A 57-year-old patient consulted for a cervical mass appearing 1 year before, with no signs of compression. The thyroid function was normal. RESULTS: The examination showed a firm tumefaction, fixed on the hyoid bone, with undetermined limits, measuring approximately 8 cm. The thyroid gland was in the normal pretracheal position. The cervical tomodensitometry objectified an osteolytic process centered on the hyoid bone with a fleshy zone of tissue density and calcifications. Cervical MRI provided a more precise assessment of the extension of the mass and confirmed the integrity of the other structures, in particular the endo-larynx. The tumor was totally resected via a cervical approach. The pathologic study suggested a papillary adenocarcinoma on ectopic thyroid tissue. The treatment was completed by a total thyroidectomy with normal histological results. CONCLUSIONS: Papillary adenocarcinoma on ectopic thyroid is a very rare situation. Its diagnosis is histological. Its treatment is primarily surgical, sometimes associated with radioiodine I-131 therapy.

Escherichia coli ribonuclease III: affinity purification of hexahistidine-tagged enzyme and assays for substrate binding and cleavage.

It is now evident that members of the RNase III family of nucleases have central roles in prokaryotic and eukaryotic RNA maturation and decay pathways. Ongoing research is uncovering new roles for RNase III homologs. For example, the phenomena of RNA interference (RNAi) and posttranscriptional gene silencing (PTGS) involve dsRNA processing, carried out by an RNase III homolog. We anticipate an increased focus on the mechanism, regulation, and biological roles of RNase III orthologs. Although the differences in the physicochemical properties of RNase III orthologs, and distinct substrate reactivity epitopes and ionic requirements for optimal activity, may mean that the protocols describe here are not strictly transferrable, the affinity purification methodology, and substrate preparation and use should be generally applicable.

[Chordoma: atypical mediastinal mass. Report of a case]. / Le chordome: une masse médiastinale atypique. A propos d'un cas.

Chordoma is a rare tumor which develops from remnant notochord tissue. Sacro-coccygeal and spheno-occipital localizations predominate. We report a thoracic chordoma of the fifth thoracic vertebra with mediastinal expansion in a 70-year-old woman. Pathology confirmed the diagnosis revealing a lobulated architecture, presence of physaliphorous cells and intracellular mucoid substance. Immunohistochemistry can also be very helpful in atypical cases: positive for anti-cytokeratine, antivimetin and anti-protein S100 antibodies. Spontaneous outcome is fatal. Early and complete resection is the only way to improve prognosis.

Specific binding of melatonin by purified cell nuclei from spleen and thymus of the rat.

In the present paper, we show that pineal hormone melatonin interacts with purified cell nuclei from rat spleen and thymus. Binding of 2-[125I]iodomelatonin ([125I]melatonin) by cell nuclei fulfills all criteria for binding to a receptor site. Binding exhibited properties such as dependence on time and temperature as well as reversibility, saturability, high affinity, and specificity. Results suggested binding to single classes of binding sites. The dissociation constants (Kd) for the binding sites in the spleen and thymus nuclei were 68 and 102 pM, respectively. These data are in close agreement with data obtained from kinetic studies, in which the kinetically derived values of the dissociation constant in the spleen and thymus nuclei were 166 and 537 pM, respectively. The affinities for melatonin of these nuclear binding sites suggest that they may recognize the physiological concentrations of melatonin in the tissues. Finally, we have demonstrated that binding of [125I]melatonin by the nuclei is displaced by CGP 52608, a specific ligand of the putative nuclear melatonin receptor RZR/ROR. Results strongly suggest that in addition to membrane receptor-related mechanisms, nuclear receptors may be involved in the regulation of immune system by melatonin.

Differential adrenergic regulation of rat pineal cyclic AMP production and N-acetyltransferase activity during postnatal development: involvement of G alpha s and G alpha i1-2 proteins.

We have studied why rat pineal N-acetyltransferase (NAT) activity is relatively insensitive to isoproterenol in young rats when compared with adult rats. We report that activation by isoproterenol of pineal cyclic AMP production and NAT activity is higher in adult than in 2-week-old rats. However, the effect of dibutyryl cyclic AMP, which enters the pinealocyte and duplicates the effect of cyclic AMP, on NAT activity was similar at both ages. Moreover, we found that both alpha- and beta-adrenergic receptors are highly specific at both ages, since the binding of the specific radioligands used to their receptors could be displaced only by their corresponding agonists and antagonists. However, we observed differences between pineals from young and adult rats when several families of the alpha subunit of G-proteins were studied in cell membranes. ADP-ribosylation and immunoblot studies have shown clear differences in both 42 and 45 kDa forms of the Gs alpha Both forms exhibit low values in pineals from 2-week-old animals when compared with 6-week-old. We also show that the later appearance of both Gs alpha forms is roughly similar to the potent activation of cyclic AMP production and NAT activity in adult rats when compared with young rats. In conclusion, the results presented suggest that the relative lack of sensitivity of rat pineal gland to beta-adrenergic receptor agonists early in the postnatal development may be explained by the low levels of membrane Gs alpha, rather than postreceptor-mediated mechanisms or changes in the characteristics of the beta-adrenergic receptors on the pinealocyte membrane.

Binding of [125I]iodocyanopindolol by rat harderian gland crude membranes: kinetic characteristics and day-night variations.

The Harderian glands are innervated by sympathetic fibers originating in the superior cervical ganglia. The aim of this study is to characterize the beta-adrenergic receptors in the rat Harderian gland. The characteristics of beta-adrenergic receptors were determined in crude membrane preparations from rat Harderian gland, using [125I]iodocyanopindolol ([125I]CYP) as radioligand. The binding of the ligand to the receptor is rapid, reversible, saturable, specific and dependent on time, temperature and membrane concentration. At 30 degrees C, stoichiometric data suggest the presence of one binding site with a Kd value of 0.29 nM and Bmax of 32 pmol/L. The interaction shows a high degree of specificity for beta-adrenergic agonists and blockers, as suggested by competitive displacement experiment with isoproterenol (IC50 = 19.1 nM), propranolol (IC50 = 28.1 nM), and norepinephrine (IC50 = 96.3 nM). Clonidine, yohimbine, methoxamine, and prazosin are ineffective at concentrations up to 1 microM. In the other hand, binding of [125I]CYP by Harderian gland membranes exhibits day-night variations. Binding values are low during the daytime and increase progressively late in the evening to reach a maximum at 2200 h (2 h after the onset of dark period), but decreased to the end of the dark period (0600 h). In conclusion, the results presented in this paper show the functional and pharmacological characterization of beta-adrenergic receptors in the rat Harderian gland. This neurotransmitter may play a physiological role at this level regulating, at least, processes such as a thyroid hormone metabolism.

Characterization of binding sites for beta-adrenergic agonists and vasoactive intestinal peptide in the rat harderian gland.

Vasoactive intestinal peptide (VIP) receptors and beta-adrenergic receptors were investigated in rat Harderian gland membranes using 125I-VIP and 125I-cyanopindolol (125I-CYP), respectively, as ligands. The receptor bindings were rapid, reversible, saturable, specific, and dependent on time, temperature, and membrane concentration. The stoichiometric data suggested the presence of two classes of VIP receptors with Kd values of 0.36 and 65.37 nM and binding capacities of 323 and 39,537 fmol VIP/mg protein, respectively. The interaction showed a high degree of specificity, as suggested by competitive displacement experiments with several peptides structurally or not structurally related to VIP as follows: VIP > helodermin > rGRF > PHI > > secretin. Glucagon, somatostatin, insulin, and pancreastatin were ineffective at concentrations up to 1 microM. However, the stoichiometric data suggest the presence of one class of binding sites for 125I-CYP. The Kd for the single site was 290 pM with a binding capacity of 32 pmol/L. The pharmacological characterization of 125I-CYP binding to membranes showed that only isoproterenol, a beta-adrenergic agonist, and norepinephrine, an alpha beta-adrenergic agonist, was as effective as propranolol in inhibiting 125I-CYP binding to Harderian gland membranes. However, alpha 1- and alpha 2-adrenergic agonists and blockers such as methoxamine, prazosin, clonidine, and yohimbine were shown to be ineffective. These results demonstrate the presence of specific VIP and beta-adrenergic receptors in the Harderian gland and suggest a role for VIP and beta-adrenergic agonists in the physiology of this gland.

Specific binding of 2-[125I]iodomelatonin by rat splenocytes: characterization and its role on regulation of cyclic AMP production.

In the present paper we show that pineal hormone melatonin interacts with rat splenocytes through high-affinity binding sites. Binding of 2-[125I]iodomelatonin ([125I]MEL) by splenocytes fulfills all criteria for binding to a receptor site. Binding exhibited properties such as dependence on time and temperature as well as reversibility, saturability, high affinity, specificity, and increased under constant light exposure. Results suggest binding to a single class of binding sites without cooperative interactions. The dissociation constant (Kd) for the single site was 0.34 nM with a binding capacity of 2.25 fmol/10(7) cells. These data are in close agreement with data obtained from kinetic studies, in which the kinetically derived value of the dissociation constant was 0.20 nM. The affinity of these binding sites suggests that they may recognize the physiological concentrations of melatonin in serum. Moreover, pharmacological doses of melatonin also inhibited cyclic AMP production stimulated by forskolin, a potent activator of adenylate cyclase system. The demonstration of [125I]MEL binding sites in the spleen, in addition to those described in blood mononuclear cells and thymus, provides evidence to support a direct mechanism of action of melatonin on immune system.

Different sensitivity of rat pineal N-acetyltransferase to alpha- and beta-adrenergic receptor agonists during development: in vitro studies.

Herein, we investigate the mechanisms involved in the adrenergically mediated stimulation of rat pineal N-acetyltransferase (NAT) activity during development using an in vitro model. Compared with adults, results suggest a different regulation of pineal NAT activity in growing rats where a similar efficiency of alpha- and beta-adrenergic receptor agonists is observed during the 1st weeks of age for activating the enzyme. In adult rats, beta- but not alpha-adrenergic receptors appear to play the preeminent role. The results indicate that the adrenergic receptor agonists used acted in a non-specific manner by binding to relatively immature receptors early during development.