A novel mutation in PRKAR1A gene in a patient with Carney complex presenting with pituitary macroadenoma, acromegaly, Cushing's syndrome and recurrent atrial myxoma

SUMMARY Carney complex (CNC) is a rare syndrome of multiple endocrine and non-endocrine tumors. In this paper we present a 23-year-old Iranian woman with CNC who harbored a novel mutation (c.642dupT) in PRKAR1A gene. This patient presented with pituitary macroadenoma, acromegaly, recurrent atrial myxoma, Cushing's syndrome secondary to primary pigmented nodular adrenocortical disease and pigmented schwanoma of the skin. PRKAR1A gene was PCR amplified using genomic DNA and analyzed for sequence variants which revealed the novel mutation resulting in substitution of amino acid cysteine instead of the naturally occurring valine in the peptide chain and a premature stop codon at position 18 (V215CfsX18). This change leads to development of tumors in different organs due to lack of tumor suppressive activity secondary to failure of synthesis of the related protein.

Dental pulp stem cells express proteins involved in the local invasiveness of odontogenic myxoma

Little is known about the histogenesis of the odontogenic myxoma (OM). Dental pulp stem cells could be candidate precursors of OM because both OM and the dental pulp share the same embryological origin: the dental papilla. For the purpose of comparing OM and stem cells, this study analyzed the expression of two proteins related to OM invasiveness (MMP-2 and hyaluronic acid) in human immature dental pulp stem cells (hIDPSCs). Three lineages of hIDPSCs from deciduous and permanent teeth were used in this study. Immunofluorescence revealed positive reactions for MMP-2 and hyaluronic acid (HA) in all hIDPSCs. MMP-2 appeared as dots throughout the cytoplasm, whereas HA appeared either as diffuse and irregular dots or as short fibrils throughout the cytoplasm and outside the cell bodies. The gene expression profile of each cell lineage was evaluated using RT-PCR analysis, and HA was expressed more intensively than MMP-2. HA expression was similar among the three hIDPSCs lineages, whereas MMP-2 expression was higher in DL-1 than in the other cell lines. The expression of proteins related to OM invasiveness in hIDPSCs could indicate that OM originates from dental pulp stem cells.

Appraisal of histogenesis of cardiac myxoma: our experience of 78 cases and review of literature.

Cardiac tumours are uncommon. Of these, myxomas have generated significant interest, not only because it is the commonest cardiac neoplasm but also because of controversial theories regarding its histogenesis. We encountered 78 cases of cardiac myxoma in our centre between 1976 and 1997. These included 73 sporadic cases and five cases from a single family of mother, daughter and son. The familial cases had recurrent, biatrial cardiac myxomas. Histopathologic analysis, immunohistochemical study, electron microscopic evaluation and DNA ploidy analysis done in some of these cases revealed evidence in support of the neoplastic nature of this entity. This communication sums up our observations and literature related to the histogenesis of cardiac myxoma.

DNA ploidy and proliferative index of cardiac myxoma.

Cardiac myxoma is the commonest tumour of heart. The histogenesis of this lesion is controversial as its origin has often been debated between the thrombogenic and neoplastic theories. We analysed DNA ploidy and proliferation indices of 30 cardiac myxomas which include 25 sporadic and five familial cases by image cytometry and proliferating cell nuclear antigen immunostaining. Of the 25 cases, 18 were aneuploid, three diploid and four tetraploid. Four of the five familial cases including the recurrent lesions were aneuploid. Poor tissue preservation precluded ploidy analysis in one familial case. The proliferation index of the sporadic cases ranged from 0.4 to 36.1 percent. The familial cases showed proliferation index between 10.2 and 22 percent. In addition to cardiac myxoma, proliferation index was assessed in 10 cardiac thrombi where it ranged from three to 58 percent. This study suggests that cardiac myxoma can be best interpreted as a neoplasm with a slow growth potential.

Lentiginosis cutaneomucosa y mixonas cutaneos y cardiacos: complejo de Carney / Cutaneo-mucosal lentiginosis and cutaneous and cardiac myxoma: corney complex

Se presenta un niño de 12 años, con múltiples mixomas cutáneos y lentiginosis cuataneo-mucosa de pocos años de evolución; con el antecedente de haber sido operado a los 8 años de un mixoma cardíaco. El padre falleció a los 34 años de un carcinoma tiroideo. A este síndrome, con herencia autosómica dominante, se lo conoció con acrósticos inadecuados como NAME y LAMB. Está constituido por 1) pequeñas lesiones hiperpigmentadas cutaneomuosas (lentigos simples y nevos azules), que de no estar atento, pueden pasar desapercibidas; 2) tumores mixomatosos (mixomas cardíacos y cutaneosmucosos, fibromas mixoides de mamas y tricofoliculoma con estroma mixoide); 3) desórdenes endocrinológicos (displasia adrenocortical micronodular, distintos tumores testiculares y adenomas pituirarios productores de hormona del crecimiento) y 4) más raramente por tumores neuroectodérmicos melanocíticos, semejantes a Schwannomas. Los marcadores cutaneomucosos son los primeros en exteriorizarse, de allí la importancia de saber reconocerlos, ya que permitirían orientar la búsqueda de las otras manifestaciones internas; especialmente los mixomas cardíacos, por ser estos los causantes de severas complicaciones y aun la muerte de los pacientes; como así también, dirigir el estudio de los familiares (ecografías). Estas últimas consideramos deben ser obligatorias en todo paciente portador de un tumor cutáneo con caracteres de angiomixoma, mixoma con rasgos neuroides o mixoma com componentes epiteliais anexiales