Síndrome del nevus melanocítico congénito. Serie de casos / Congenital Melanocytic Nevus Syndrome: A Case Series

El síndrome del nevus melanocítico congénito (SNMC) consiste en la proliferación anormal de melanocitos en la piel y el sistema nervioso central, y se debe a mutaciones de las células progenitoras durante el desarrollo embrionario. En muchas de estas células se han detectado mutaciones en el gen NRAS. Se exponen 5 casos de nevus melanocítico congénito gigante, 3 de ellos asociados al SNMC, en los que se ha estudiado dicha mutación. Hasta hace unos años la cirugía era el tratamiento de elección, sin embargo, sus resultados son insatisfactorios, con cirugías agresivas que no mejoran el aspecto estético y reducen mínimamente el riesgo de malignización. En el año 2013 se aprobó el trametinib en el uso del melanoma avanzado con mutaciones de NRAS. Dicho fármaco, que participa en la cascada intracelular de RAS-RAF-MEK-pERK-MAPK, podría ser útil en pacientes pediátricos con SNMC. El conocimiento más amplio de esta enfermedad permitirá crear nuevas estrategias (AU)

Congenital melanocytic nevus syndrome (CMNS) is the result of an abnormal proliferation of melanocytes in the skin and central nervous system caused by progenitor-cell mutations during embryonic development. Mutations in the NRAS gene have been detected in many of these cells. We present 5 cases of giant congenital melanocytic nevus, 3 of them associated with CMNS; NRAS gene mutation was studied in these 3 patients. Until a few years ago, surgery was the treatment of choice, but the results have proved unsatisfactory because aggressive interventions do not improve cosmetic appearance and only minimally reduce the risk of malignant change. In 2013, trametinib was approved for use in advanced melanoma associated with NRAS mutations. This drug, which acts on the intracellular RAS/RAF/MEK/pERK/MAPK cascade, could be useful in pediatric patients with CMNS. A better understanding of this disease will facilitate the development of new strategies (AU)

Congenital basis of posterior fossa anomalies.

The classification of posterior fossa congenital anomalies has been a controversial topic. Advances in genetics and imaging have allowed a better understanding of the embryologic development of these abnormalities. A new classification schema correlates the embryologic, morphologic, and genetic bases of these anomalies in order to better distinguish and describe them. Although they provide a better understanding of the clinical aspects and genetics of these disorders, it is crucial for the radiologist to be able to diagnose the congenital posterior fossa anomalies based on their morphology, since neuroimaging is usually the initial step when these disorders are suspected. We divide the most common posterior fossa congenital anomalies into two groups: 1) hindbrain malformations, including diseases with cerebellar or vermian agenesis, aplasia or hypoplasia and cystic posterior fossa anomalies; and 2) cranial vault malformations. In addition, we will review the embryologic development of the posterior fossa and, from the perspective of embryonic development, will describe the imaging appearance of congenital posterior fossa anomalies. Knowledge of the developmental bases of these malformations facilitates detection of the morphological changes identified on imaging, allowing accurate differentiation and diagnosis of congenital posterior fossa anomalies.

[Multiple congenital smooth-muscle hamartomas]. / Hamartomes musculaires lisses congénitaux multiples.

BACKGROUND: Smooth muscle hamartoma is an uncommon lesion. Diagnosis is usually made at birth in infants presenting a plaque with minimal or no infiltration and covered with long dark hairs. Congenital forms with multiple plaques are rarely reported. CASE REPORT: A 5-day-old infant (normal pregnancy and delivery) had plaques localized on the buttocks, the left thigh, leg and shoulder and the right ankle. The plaques were minimally infiltrative and covered with long black hairs. Histology examination showed hyperplastic smooth muscle bundles with varying orientation. The diagnosis was smooth muscle hamartoma. The rest of the clinical examination was normal. CONCLUSION: This case of congenital smooth muscle hamartoma showed a particular form with partially regressive multiple plaques.

Congenital hypothalamic hamartoma syndrome: nosological discussion and minimum diagnostic criteria of a possibly familial form.

We report on congenital hypothalamic hamartomas, discovered at autopsy in 3 unrelated fetuses. In the first 2 patients, the tumor was associated with skeletal dysplasia only. In the third patient, it was part of a non-random congenital malformation association, suggestive of Meckel syndrome. In one family, a previous boy died soon after birth with similar craniofacial and skeletal abnormalities. As far as we know, the association between isolated skeletal dysplasia and congenital hypothalamic hamartomas has not yet been documented in the literature. Nevertheless, a spectrum of skeletal abnormalities has been described in association with congenital hypothalamic "hamartoblastoma" and a constellation of variable visceral malformations under the eponym of "Pallister-Hall syndrome" (PHS). A detailed analysis of the PHS reported cases shows that only skeletal dysplasia and oro-facial abnormalities are present constantly. They show similarities with those found in our first 2 cases. These findings prompt us to consider skeletal dysplasia and oro-facial abnormalities as common denominator and minimum criteria required to define a nosologically distinct, possibly familial entity, which we suggest calling "congenital hypothalamic hamartoma syndrome" (CHHS).

Cystic hamartomata of lung and kidney: a spectrum of developmental abnormalities.

We report on a developmental malformation of the lung and kidney which has not been previously described and which we have chosen to call "cystic hamartomata of the lung and kidney" to emphasize the non-malignant nature of these lesions. We also confirm a previous case report by Weinberg and Zumwalt [1977] as a different distinct disorder that results in a multifocal cystic hamartomata of the lung with associated marked parenchymal overgrowth of the kidney (the Weinberg-Zumwalt syndrome). These cases represent a spectrum of abnormal morphogenesis affecting both kidney and lung. Patients 1 and 2 presented during infancy with abdominal masses and hypertension due to bilateral multilocular cysts of the kidney with associated hamartomatous pulmonary cysts; patient 2 also had one area of cellular mesoblastic nephroma. Patient 3 demonstrated markedly hyperplastic renomegaly with medullary dysplasia in association with bilateral cystic hamartomata of the lungs. During the fifth week of gestation, the ureteric bud invades the unsegmented mesoderm that becomes the metanephric system, and the lung bud invades the splanchic mesoderm, which provides the stimulus for its growth. We suggest that the predominant pattern of a congenital kidney or lung hamartoma might reflect the timing of a prenatal neoplastic event affecting these developmental processes.