Rosa Mónica Drut

Testicular microlithiasis: histologic and immunohistochemical findings in 11 pediatric cases.

Testicular microlithiasis (TM) is being recognized with increasing frequency because of the extensive use of ultrasound. TM has been linked to several pathological conditions of the testis, mainly with an increased risk for developing germ cell tumors. The pathogenesis of the microcalcospherites is unknown. We report a detailed morphologic and immunohistochemical analysis of 11 patients (age: 3 to 15 years) with TM. The microliths were related neither to the age of the children nor to the developmental stage of the testis. The microcalcospherites were PAS positive or collagen IV positive or surrounded by a collagen IV–positive band, extratubular structures consistently associated with double-layered annular tubules. Immature, smaller Sertoli cells commonly lined the inner layer of the annular tubules. Some microcalcospherites showed an interposed thin band of connective tissue cells between the concretion and the tubular basement membrane. The annular tubules seemed to result from progressive wrapping of the growing tubules around the concretions. Our findings favor the interpretation that the microliths are located outside the tubules and have been present there since very early stages of testicular development. The association of the calcospherites with Sertoli cells and annular tubules formation, like that of gonadal stromal tumor with annular tubules of the ovary and large cell–calcifying Sertoli cell tumor of the testis, favors the hypothesis that microliths may result from multifocal Sertoli cell dysfunction. Since both tumors are related to the Peutz-Jeghers syndrome, it is proposed that TM may result from the same genetic abnormalities. It is unclear how this may be related to the development of germ cell tumors. However, the presence of calcospherites in gonadoblastoma may indicate a combined Sertoli cell and germ cell derangement in the genesis of TM.

HEPATIC HEMANGIOENDOTHELIOMAS, PLACENTAL CHORIOANGIOMAS, AND DYSMORPHIC KIDNEYS IN BECKWITH-WIEDEMANN SYNDROME

A 4-month-old female, birth weight 3150 g, had a history of maternal eclampsia, multiple placental chorioangiomas, and persistent neonatal hypoglycemia. Macroglossia and enlarged kidneys were recorded. Autopsy revealed multiple hepatic hemangioendotheliomas (type 1), massive cardiomegaly, and bilateral nephromegaly. Both kidneys were lobulated with active glomerulogenesis and clusters of immature tubules and foci of dysplastic medullary ducts. The features suggest that the nephrogenesis was secondary to the persistence of actively branching nephron-inducing ducts. Nodular hyperplasia of the adrenal cortex (adrenoblastomatosis) was present. This report expands the list of tumors to be found in Beckwith-Wiedemann syndrome (BWS).

Nonimmune fetal hydrops and placentomegaly : diagnosis of familial Wiedemann-Beckwith Syndrome with trisomy 11p15 using FISH

We have studied a family in which four members of the same generation were affected with Wiedemann-Beckwith syndrome (WBS). Trisomy 11p15 was demonstrated using molecular probes in interphase nuclei of formalin-fixed paraffin-embedded placenta from a stillborn fetus and in peripheral blood lymphocytes from two liveborn female relatives. Clinical examination showed nonimmune hydrops and placentomegaly in two siblings and multiple phenotypic abnormalities consistent with WBS in the two other relatives. Paternal karyotype of the stillborn infants demonstrated a reciprocal translocation (46,XY,t(10;11) (q26;p15)) explaining the origin of the extra 11p15 material. This study illustrates the advantages of FISH for interphase analysis of chromosome aberrations otherwise not detected even by conventional cytogenetic analysis and documents that nonimmune hydrops associated with placentomegaly may be the presenting features in familial WBS.

Thyrocalcitonin-containing cells in the Di George anomaly

The Di George syndrome is an anomaly characterized by the complete or partial absence of derivatives of the third and fourth pharyngeal pouches often associated with defective development of the third, fourth, and sixth aortic arches leading to absence or hypoplasia of the thymus and parathyroid glands and to cardiovascular anomalies. The fifth pharyngeal pouch, often considered a part of the fourth pouch, gives rise to the ultimobranchial body (UB), which becomes incorporated into the thyroid gland and is thought to be the source of thyroid C cells. Robinson suggested that complete or partial absence of the UB should be considered a part of the Di George anomaly. To substantiate this theory, the thyroid glands of 11 patients with the Di George syndrome and 11 age-matched control infants were examined immunohistochemically using the immunoperoxidase technique for presence or absence of thyrocalcitonin (TC)-containing cells. Only three of 11 patients with the Di George syndrome had TC-containing cells in their thyroid glands (27 per cent), and nine of 11 control infants had these cells (82 per cent). It is concluded that thyroid C cell deficiency is present in most patients with Di George anomaly, suggesting a relationship between these cells and development of derivatives of the third through fifth visceral pouches. Furthermore, there is a spectrum of deficiency of thyroid C cells in these individuals comparable with the spectrum of partial to complete absence of third and fourth pharyngeal pouch derivatives regarding thymus and parathyroid glands. Immunostaining for TC of the lungs of all infants with the Di George syndrome and control infants revealed similar numbers of thyrocalcitonin-containing cells in both groups. Asynchronous development of thyroid and lung thyrocalcitonin-containing cells in those with the Di George syndrome favors the theory that the latter develop independently of derivatives of the third through fifth visceral pouches. This study further supports a neural crest origin of the Di George anomaly and strengthens the concept that the Di George anomaly is a neurocristopathy.

EBV-Associated Kaposi's Sarcoma in a Pediatric Renal Transplant Recipient

A 7-year-old boy had undergone kidney transplantation for chronic renal failure secondary to bilateral renal hypoplasia. He developed acute and chronic rejection and received immunosuppressive therapy. A year later he died with EBV-associated hemophagocytic syndrome. The main pathologic findings disclosed visceral (lung and stomach) and abdominal lymph node involvement of Kaposis sarcoma and EBV-positive immunoblasts in several organs. In the lungs and lymph nodes these had the features of polymorphous lymphoimmunoblastic lesions. Because of the peculiar distribution of Kaposis sarcoma lesions a pathogenetic hypothesis is proposed based on the site of entry of the virus. This case contributes to expanding the relationship between Kaposis sarcoma and kidney transplantation in the pediatric population.

Use of Fluorescent in Situ Hybridization to Detect Trisomy 13 in Archival Tissues for Cytogenetic Diagnosis

The present report describes the use of molecular probes to investigate the chromosomal constitution of interphase nuclei of formalin-fixed, paraffin-embedded tissue from three infants with multiple congenital malformations and a provisional diagnosis of trisomy 13 in two. Fluorescent in situ hybridization with the probe for the 13 and 21 centromeric regions revealed five nuclear signals in two of the cases, indicating the presence of an extra chromosome, and only four nuclear signals in the other case. Only the two positive cases had phenotypic features consistent with trisomy 13. Routine cytogenetic analysis was performed on one child and confirmed an additional chromosome 13. The child without an extra chromosome had features consistent with Ivemark syndrome. This study demonstrates the utility of fluorescent DNA probes for the retrospective diagnosis of aneuploidies in archival material.

Giant-Cell Myocarditis in a Newborn with Congenital Herpes Simplex Virus (Hsv) Infection: an Immunohistochemical Study on the Origin of the Giant Cells

Giant-cell myocarditis is a rare inflammatory disorder characterized by degeneration and necrosis of myocardial fibers and presence of chronic inflammatory infiltrates associated with multinucleated giant cells forming a granulomatous inflammatory reaction. The etiology of giant-cell myocarditis is unknown. Many conditions have been reported as associated with this phenomenon such as fungi, virus, sarcoidosis, and hypersensitivity or autoimmune reactions. We are reporting a case of giant-cell myocarditis discovered in a newborn with congenital herpetic sepsis. The myogenic origin of the giant-cells of this case is supported by the positivity for desmin and myoglobin and negativity for muramidase and alpha-1-antichymotrypsin after immunoperoxidase procedure. The presence of Herpes simplex virus type II was confirmed by indirect immunoperoxidase reaction in most of the viscera including the heart, but is not considered a factor in the production of giant cells.

Solitary Unilocular Cyst of the Lung with Features of Persistent Interstitial Pulmonary Emphysema: Report of Four Cases

ABSTRACT Neonatal interstitial pulmonary emphysema (IPE) is a well-characterized lesion usually presenting in preterm newborns as a complication of respiratory distress syndrome and/or assisted ventilation. Occasionally, IPE may occur spontaneously in infants with no underlying pulmonary disease. Persistence of IPE (PIPE) may be diffuse or localized. Localized PIPE usually presents as multiple cysts 0.3 to 3 cm in one or more lobes of the lung. In this report, we describe four cases of unilocular large cysts (up to 5 cm in diameter) partially lined by uni- and multinucleated histiocytes in a foreign body type reaction and showing gas dissection of the surrounding parenchyma (present in case 1). These histological features favored the diagnosis of PIPE and the cases were interpreted as such, since no other clear-cut diagnosis could be defined. However, because the lesion was limited to one lobe, and the children were full term, asymptomatic at birth and without history of respiratory distress or assisted ventilation, differential diagnosis with other pulmonary cystic lesions of infancy is mandated.

Yolk sac tumor of the placenta in Wiedemann-Beckwith syndrome.

ABSTRACT The present report describes an example of multifocal (two) yolk sac tumor (YST) with mesenchyme-like and enteroid patterns found in the placenta (730 g) of a newborn (4200 g) with Wiedemann-Beckwith syndrome (WBS) phenotype (macroglossia, omphalocele, hemihypertrophy, cardiomegaly, hypoglycemia). YST has not been previously reported to develop in the placenta. This case expands further the spectrum of alterations found in the placenta in the WBS and fits in the list of tumors related to WBS. {KW}Key words: Wiedemann-Beckwith syndrome, yolk sac tumor, placenta

Adnexal-Centered Giant Congenital Melanocyte Nevus with Extensive Ganglioneuromatous Component and Trisomy 7

ABSTRACT Adequate interpretation of clinical and histopathologic features of giant congenital melanocytic nevus (GCMN) in newborns is a continued challenge. A GCMN with three large nodules and three polypoid exophytic tumors presented in the dorsum of a female full-term newborn, the borders exhibiting a spotted grouped pattern. Microscopic examination revealed a peculiar adnexal-centered (eccrine sweat gland ducts, acrosiringia, and hair infundibula) compound nevus expressing pagetoid intraepidermal spreading of epithelioid melanocytes. The nodules represented an extensive ganglioneuromatous component. The neurons and their neuropil were positive for neuron-specific enolase, S-100, synaptophysin, tyrosine hydroxilase, and PGP 9.5. In addition to these components, a poorly differentiated, fusiform, low-mitotic rate population of cells undergoing epithelioid differentiation (and probably neuronal differentiation) with nodular arrangement was also present in the polypoid tumors and deeper parts of the nevus, in part intermixed with the neurons. These cells were vimentin positive but S-100 negative. FISH studies revealed these cells to express three signals for the centromeric probe for chromosome 7 whereas the neuronal component showed just two. Adnexal-centered arrangement of melanocytes has not been emphasized in GCMN. Ganglioneuromatous differentiation has been rarely reported in this condition. Trisomy 7 in GCMN has been reported only once previously.