A missing kidney and a hidden congenital diaphragmatic hernia

Congenital intrathoracic kidney (ITK) is a rare condition, which is usually discovered incidentally in asymptomatic children who do not need any intervention. However, it may be associated with congenital diaphragmatic hernia (CDH), in which case it requires urgent surgical intervention. We present a case of prenatally diagnosed ITK associated with a left CDH that was operated on day 5 of life. The neonate is currently well at 15 months of age.

Ectopic pancreas: a rare cause of abdominal pain

We present a case of recurrent abdominal pain due to an ectopic or heterotopic pancreas. Heterotopic pancreas (HP) is the presence of histologic pancreatic tissue outside its normal location without any anatomic or vascular continuity with the pancreas. The frequency of HP has been estimated as 0.6-13.7%. Most are found in the duodenum, stomach, andjejunum. The exact mechanism remains controversial but it has been theorized that it most likely arises congenitally during embryonic development. The elevations of amylase and lipase levels are modest due to the small volume of pancreatic tissue in the HP. Therefore, diagnostic modalities including barium swallow, upper-gastrointestinal series, CT, EUS, and MRCP can be used when suspecting HP. The need for treatment is based on symptoms and definitive diagnosis, especially when the possibility of malignancy exists. Asymptomatic causes need not require treatment.

Early onset of Runx2 expression caused craniosynostosis, ectopic bone formation, and limb defects

RUNX2 is an essential transcription factor for osteoblast differentiation, because osteoblast differentiation is completely blocked in Runx2-deficient mice. However, it remains to be clarified whether RUNX2 is sufficient for osteoblast differentiation during embryogenesis. To address this issue, Runx2 transgenic mice were generated under the control of the Prrx1 promoter, which directs the transgene expression to mesenchymal cells before the onset of bone development. The transgene expression was detected in the cranium, limb buds, and the region from the mandible to anterior chest wall. The skull became small and the limbs were shortened depending on the levels of the transgene expression. Early onset of Runx2 expression in the cranial mesenchyme induced mineralization on E13.0, when no mineralization was observed in wild-type mice, and resulted in craniosynostosis as shown by the closure of sutures and fontanelles on E18.5. Col1a1 and Spp1 expressions were detected in the mineralized regions on E12.5-13.5. The limb bones were hypoplastic and fused, and ectopic bones were formed in the hands and feet. Col2a1 expression was inhibited but Col1a1 expression was induced in the limb buds on E12.5. In the anterior chest wall, ectopic bones were formed through the process of intramembranous ossification, interrupting the formation of cartilaginous anlagen of sternal manubrium. These findings indicate that RUNX2 is sufficient to direct mesenchymal cells to osteoblasts and lead to intramembranous bone formation during embryogenesis; Runx2 inhibits chondrocyte differentiation at an early stage; and that Runx2 expression at appropriate level, times and spaces during embryogenesis is essential for skeletal development.

Multicenter study of 19 aortopulmonary window parathyroid tumors: the challenge of embryologic origin

BACKGROUND

Ectopic abnormal parathyroid glands are relatively common in the superior mediastinum but are rarely situated in the aortopulmonary window (APW). The embryological origin of these abnormal parathyroid glands is controversial. The purpose of this investigation was to investigate the embryological origin and the surgical management of abnormal parathyroid glands situated in the APW.

METHODS

The databases of patients operated on for primary, secondary, and tertiary hyperparathyroidism at eight European medical centers with a special interest in endocrine surgery were reviewed to identify those with APW adenomas. Demographic features, localization procedures, and perioperative and pathology findings were documented. The embryological origin was determined based on the number and position of identified parathyroid glands.

RESULTS

Nineteen (0.24%) APW parathyroid tumors were identified in 7,869 patients who underwent an operation for hyperparathyroidism (HPT) and 181 patients (2.3%) with mediastinal abnormal parathyroid glands. Ten patients had primary, eight had secondary, and one had tertiary HPT. Sixteen patients had undergone previous unsuccessful cervical exploration. In three patients, an APW adenoma was suspected by preoperative localization studies and was cured at the initial operation. Sixteen patients had persistent HPT of whom 15 were reoperated, resulting in 6 failures. Evaluation of 17 patients who had bilateral neck exploration allowed us to determine the most probable origin of the APW parathyroid tumors: 12 were supernumerary, 4 appeared to originate from a superior, and 1 from an inferior gland.

CONCLUSIONS

Abnormal parathyroid glands situated in the APW are rare and usually identified after an unsuccessful cervical exploration. Preoperative imaging of the mediastinum and neck are essential. The origin of these ectopically situated tumors is probably, as suggested by our data, from a supernumerary fifth parathyroid gland or from abnormal migration of a superior parathyroid gland during the embryologic development.

Congenital anomalies of the spleen from an embryological point of view

The spleen is the major accumulation of lymphoid tissue in the human body, an organ which prenatally produces and postnatally controls blood cells. Normally, a developed spleen lies in the upper left quadrant in parallel with the long axis of the 10th rib. It is a mesodermal derivate which first appears as a condensation of mesenchymal cells inside the dorsal mesogastrium at the end of the fourth embryonic week. Some congenital anomalies of the spleen are common, such as splenic lobulation and accessory spleen, while other conditions are rare, such as wandering spleen and polysplenia. Splenogonadal fusion is also a rare developmental anomaly, resulting from abnormal fusion of the splenic and gonadal primordia during prenatal development. The purpose of this article is to describe the normal development of the human spleen, supplemented with our own photomicrographs and a review of congenital anomalies of the spleen with their possible embryonic basis.

''Ectopic eyelashes'' (ectopic cilia) in a 2-year-old girl: brief report and discussion of possible embryologic origin

Cilia, or eyelashes, are unique hair follicles normally found at the eyelid margin. The spectrum of cilial anomalies includes cilial row duplication, agenesis, and ectopic placement. Ectopic cilia are the most rare of cilial anomalies. We report a case of a 2-and-a-half-year-old girl with ectopic cilia of the anterior tarsal plate, an extremely rare, congenital anomaly that is most often not associated with other findings and likely results from an event during embryogenesis.

[Nasal glial heterotopia: embryological and clinical approaches]

INTRODUCTION

Nasal gliomas or heterotopia are nonhereditary congenital malformations composed of heterotopic neuroglial tissue. They usually present in infancy. Evaluation should include preoperative imaging with CT scan and/or MRI to rule out intracranial extension. There have been several cases reported in which nasal gliomas were misdiagnosed as capillary hemangiomas. The differential diagnosis includes prenasal space developmental impairment, which are nasoethmoidal meningoencephaloceles, nasal dermoid and epidermoid cysts.

CASE REPORT

We describe the case of a newborn male infant presenting at birth with a paramedial nasal glioma. An embryological and clinical analysis of nasal gliomas is proposed.

DISCUSSION

Nasal glioma is an uncommon congenital lesion presenting as a large panel of midline craniofacial anomalies. The embryological and anatomical origins of nasal gliomas are reviewed. The most known embryological theory was described by Grünwald in 1910 and is called the "prenasal space" theory. This theory is very attractive because of the embryopathogenic continuum proposed among dermoids, gliomas, and encephaloceles. In this article, we discuss major embryological theories on nasal gliomas pathogenesis and propose that while the prenasal space theory can explain the occurrence and the continuum between basal anterior or prenasal encephaloceles and gliomas, it cannot explain the occurrence of craniofacial demoids of the same topography. Better knowledge of embryological mechanisms implicated in the pathogenesis of nasal gliomas can help clinical management of this kind of malformations.

Bilateral cervical chondrocutaneous remnants: a case report and review of the literature

Cervical chondrocutaneous remnants are less common lesions, which are encountered at the lateral neck. They are similar in appearance to preauricular tags, which are more frequent. Bilateral appearance of this pathology is quite uncommon. The lesions always present at birth, and are located in the middle or lower third of the lateral neck with a significant prevalence of location anterior to the sternocleidomastoid muscle. The overlying skin is similar to the surrounding neck skin and the lesion is painless, lacking any inflammation or discharge. Surgically there is no connection with deep underlying structures. The therapy of choice should be complete surgical removal. Several associated anomalies may accompany cervical chondrocutaneous remnants. Thus these patients must be evaluated carefully in order to detect any additional anomaly. We herein report a four-year-old patient with bilateral cervical chondrocutaneous remnant located at the inferior third of the lateral neck anterior to the sternocleidomastoid muscle. We also review the literature for patients with bilateral cervical chondrocutaneous remnants and discuss embryologic and diagnostic aspects.

Molecular mechanisms underlying ectopic otoconia-like particles in the endolymphatic sac of embryonic mice

Otoconin-90, the principal otoconial matrix protein, provided a tool to investigate the molecular mechanism of otoconial morphogenesis. The endolymphatic sac of the embryonic chick and guinea pig contain otoconia. Here, we show that the embryonic mouse transiently expresses ectopic otoconia in the endolymphatic sac. Massive precipitate of otoconin-90-positive material is detectable in the lumen of the endolymphatic sac between embryonic day 14.5 and 17.5 with frequent accretion into more heavily staining otoconia-like particles. Otoconin-90 was also localized at the surface and the interior of epithelial cells lining the endolymphatic sac as well as incorporated into free floating cells. In contrast, in situ hybridization failed to detect mRNA in the endolymphatic duct and sac, even though the adjacent nonsensory vestibular structures are heavily stained. Because of ample expression of otoconin-90 protein in the absence of the corresponding mRNA, we conclude that the luminal otoconin-90 is imported via longitudinal flow from the vestibular compartments, where both mRNA and protein are strongly expressed. Because of absence of mRNA, the expression of the corresponding protein by the epithelia lining the endolymphatic sac can only be explained by a resorptive process, as previously proposed on the basis of the movement of luminal macromolecules. The data do not support the previous hypothesis that the transient expression of otoconia-like particles of the endolymphatic sac represents a vestigial phenomenon from the amphibian stage, since amphibia express ample mRNA encoding otoconin-22 in the endolymphatic sac system.

Prenatal diagnosis of enteric duplication cyst of the tongue

Cysts located on the tongue are rare and usually diagnosed in childhood. Here we report on the prenatal diagnosis of an unusual cystic malformation of the tongue with heterotopic intestinal tissue explored by prenatal ultrasound, magnetic resonance imaging and on its surgical treatment and histological examination. The prenatal differential diagnoses as well as perinatal management of cystic lesions of the tongue are reviewed.

Uncommon ureteric ectopias: embryological implications

We herein report two rare ureteric ectopias, one in the uterus, the second in the rectum. These kinds of ectopias are not easily explained with regard to the classic embryological theories of the too-cranial or too-caudal origin of the ureteric bud on the mesonephric duct. We thus set out new explanations consistent with embryological studies on the narrow contact between the developing paramesonephric and mesonephric ducts, and on the so-called cloacal septation.

A rare expression of neural crest disorders: an intrasphenoidal development of the anterior pituitary gland

Congenital abnormalities of the pituitary gland are rare and may be associated with midline cranial, orbital, and facial anomalies and with hormonal insufficiency. Here we report a case of asymptomatic, abnormal migration of the adenohypophysis. The normally developed adenohypophysis was located in the sphenoid bone and developed on the intersphenoidal septum, extending from the superior pharyngeal wall to the floor of the sella turcica (craniopharyngeal canal). The abnormal migration of the pituitary gland was isolated without hormonal deficit, brain, or facial developmental anomalies.

The pro-apoptotic gene Bax is required for the death of ectopic primordial germ cells during their migration in the mouse embryo

In the mouse embryo, significant numbers of primordial germ cells (PGCs)fail to migrate correctly to the genital ridges early in organogenesis. These usually die in ectopic locations. In humans, 50% of pediatric germ line tumors arise outside the gonads, and these are thought to arise from PGCs that fail to die in ectopic locations. We show that the pro-apoptotic gene Bax,previously shown to be required for germ cell death during later stages of their differentiation in the gonads, is also expressed during germ cell migration, and is required for the normal death of germ cells left in ectopic locations during and after germ cell migration. In addition, we show that Bax is downstream of the known cell survival signaling interaction mediated by the Steel factor/Kit ligand/receptor interaction. Together, these observations identify the major mechanism that removes ectopic germ cells from the embryo at early stages.

Intratracheal ectopic thyroid tissue: a case report and literature review

We discuss a case of intratracheal ectopic thyroid tissue (ETT) that was retrieved from the files of the Otorhinolaryngic--Head and Neck Pathology Registry at the Armed Forces Institute of Pathology. The patient was a 54-year-old man who had a history of papillary thyroid carcinoma, which had been treated with a subtotal thyroidectomy. During routine follow-up 4 years later, the patient's primary care physician detected an elevated thyroglobulin level. Further referrals and evaluations revealed that the patient had intratracheal ETT. The patient refused to undergo surgical excision and remains without evidence of recurrent carcinoma. In a MEDLINE literature review, we found only 13 other well-documented cases of intratracheal ETT since 1966; in all but two cases, patients had benign disease. Once the possibility of thyroid carcinoma has been eliminated by histologic examination, intratracheal ETT can be managed by complete surgical excision with the prospect of an excellent long-term clinical outcome.

Neurogenesis in cerebral heterotopia induced in rats by prenatal methylazoxymethanol treatment

We have previously demonstrated that the antiproliferative agent methylazoxymethanol acetate (MAM) is able to induce in rats cerebral heterotopia that share striking similarities with those observed in human periventricular nodular heterotopia (PNH), a cerebral dysgenesis frequently observed in human patients affected by drug-resistant focal epilepsy. In this study, we investigated the time-course of neurogenesis in the cerebral heterotopia of MAM-treated rats, with the idea of understanding why PNH develop in human patients. For these goals, we analyzed the cytoarchitectural features, the time of neurogenesis and the cellular phenotype of the heterotopia, by means of BrdU immunocytochemistry and confocal immunofluorescence experiments. Our data demonstrate that the different types of heterotopia in MAM-treated rats are formed through the same altered neurogenetic process, which follows quite organized neurogenetic gradients. The MAM-induced ablation of an early wave of cortical neurons is sufficient to alter per se the migration and differentiation of subsequently generated neurons, which in turn set the base for the formation of the different heterotopic structures. The neurogenesis of MAM-induced heterotopia may explain the origin and intrinsic epileptogenicity of periventricular nodular heterotopia in human patients.

Dissection of the cellular and molecular events that position cerebellar Purkinje cells: a study of the math1 null-mutant mouse

Granule cell precursors in the external germinal layer (EGL) of the cerebellum have been proposed to be a major player in the migration and positioning of Purkinje cells through the expression of the Netrin-like receptor Unc5h3 and the extracellular matrix molecule Reelin. To explore the role of the EGL on these processes, we made use of the math1 null-mutant mouse in which the EGL does not form. In the absence of the EGL, we find three populations of ectopic Purkinje cells. First, we find 1% of all Purkinje cells in a supracerebellar position at the dorsal midline. Second, we find 7% of all Purkinje cells in the inferior colliculus, similar to what is seen in the Unc5h3 mutant. Our finding that Unc5h3 expression is not disrupted in these cells supports the proposed role of EGL granule cell precursors in establishing the anterior cerebellar boundary through the expression of Unc5h3. Third, we find 20% of all Purkinje cells positioned deep to the cerebellar cortex as seen in the reeler mutant. However, unlike the reeler mutant, where 5% of the Purkinje cells migrate successfully, we find that in the math1 null that 72% of the Purkinje cells migrate successfully. This finding demonstrates that Purkinje cell migration is not solely dependent on Reelin signaling from the EGL and is likely caused by Reelin signals emanating from the nuclear transitory zone or the ventricular zone, or both.

Annular pancreas in adults: embryological development, morphology and clinical significance

Three cases (two male, one female) of annular pancreas are presented, which were found and operated on within the last three decades. Diagnosis was made using imaging techniques, especially ultrasonography and computed tomography. In two cases there was incomplete obstruction, while in the other obstruction was complete. It is characteristic that in the case of complete obstruction the annular portion of the pancreas attached to a circular band of connective tissue, while in the two cases of incomplete obstruction there was a complete ring of pancreatic tissue. In all cases surgical intervention was needed in order to create a bypass. In the first case gastroenterostomy and truncal vagotomy was performed, in the second latero-lateral duodeno-jejunostomy and in the third latero-lateral antropyloroduodeno-jejunostomy. The embryology and morphology of the annular pancreas, the morphology of its duct system, diagnosis, differential diagnosis and the surgical treatment of this rare condition are reviewed.

Isolated extraabdominal colonic tissue: What do we know about it?

A newborn presenting with an isolated ectopic colonic tissue arising from the vulva without any associated anomaly is reported. The clinicopathologic features of this rare entity are discussed with special emphasis on embryologic basis.

Rescue of ataxia and preplate splitting by ectopic expression of Reelin in reeler mice

The gene mutated in reeler (reelin) encodes a protein secreted by neurons in the developing brain that controls laminar positioning of migrating cells in the CNS by an unknown mechanism. To investigate Reelin function, we used the nestin promoter to express Reelin ectopically in the ventricular zone and other brain regions in transgenic mice. In the presence of the endogenous protein, ectopic Reelin did not alter cell migration in the neocortex or the cerebellum. However, in the reeler background, ectopic Reelin induced tyrosine phosphorylation of Dab-1 in the ventricular zone and rescued some, but not all, of the neuroanatomic and behavioral abnormalities characteristic of reeler. These results indicate that Reelin does not function simply as a positional signal. Rather, it appears to participate in multiple events critical for neuronal migration and cell positioning.

Pancreatic heterotopia and other uncommon causes of non-malignant biliary obstruction

The vast majority of patients developing obstructive jaundice will have an underlying malignancy. When the etiology of the obstruction cannot be defined prior to operative intervention, identification of a non-malignant process will occur only subsequent to a major operation. The clinical course of a patient with complete distal common bile duct obstruction as the result of pancreatic heterotopia is discussed. This uncommon diagnosis prompted a review of the literature on this subject enabling this detailed discussion inclusive of the embryology, prevalence and clinical presentations of this entity. Our review further identified a varied group of other non-malignant causes of biliary obstruction that may be mistakenly interpreted to represent biliary or pancreatic malignancy.

[Unusual testicular tumor: an ectopic spleen]

The authors report a case of discontinuous splenogonadal fusion diagnosed after left orchidectomy. Ectopic spleen in the scrotum is a rare congential anomaly frequently associated with other anomalies, especially limb defects. The diagnosis is difficult. Preoperative isotope scanning and intraoperative pathological examination can be performed to avoid unnecessary orchidectomy.

[Complete supernumerary breast on the thigh in a male patient]

BACKGROUND

Supernumerary nipples are not rare but the developement of a complete supernumerary breast is exceptional.

CASE REPORT

A 59-year-old man presented a progressively increasing ancient right- groin-masse. The histopathologic examination of the lesion confirmed the diagnostic of polymastia.

DISCUSSION

The interest of this observation results from the very unusual occurence of polymastia (less than 1 p. 100 of supernumerary nipples), especially for a caucasian man. The prevalence appears to be higher in women and oriental people. Diagnostic of supernumerary nipple is difficult because of its atypical appearance and ectopic location. However, this diagnostic is important because ectopic breast tissue is subject to the same pathologic changes that occur in normally positioned breasts and it can be a marker for associated diseases such as urologic malformations or urogenital malignancies.

Ectopic scrotum and patent urachus

Ectopic scrotum is a rare condition and has been reported in association with other urological abnormalities. We present a case with an associated patent urachus and a brief discussion on the possible mechanism to explain this deformation.

Loss of orphan receptor germ cell nuclear factor function results in ectopic development of the tail bud and a novel posterior truncation

The dynamic embryonic expression of germ cell nuclear factor (GCNF), an orphan nuclear receptor, suggests that it may play an important role during early development. To determine the physiological role of GCNF, we have generated a targeted mutation of the GCNF gene in mice. Germ line mutation of the GCNF gene proves that the orphan nuclear receptor is essential for embryonic survival and normal development. GCNF(-/-) embryos cannot survive beyond 10.5 days postcoitum (dpc), probably due to cardiovascular failure. Prior to death, GCNF(-/-) embryos suffer significant defects in posterior development. Unlike GCNF(+/+) embryos, GCNF(-/-) embryos do not turn and remain in a lordotic position, the majority of the neural tube remains open, and the hindgut fails to close. GCNF(-/-) embryos also suffer serious defects in trunk development, specifically in somitogenesis, which terminates by 8.75 dpc. The maximum number of somites in GCNF(-/-) embryos is 13 instead of 25 as in the GCNF(+/+) embryos. Interestingly, the tailbud of GCNF(-/-) embryos develops ectopically outside the yolk sac. Indeed, alterations in expression of multiple marker genes were identified in the posterior of GCNF(-/-) embryos, including the primitive streak, the node, and the presomitic mesoderm. These results suggest that GCNF is required for maintenance of somitogenesis and posterior development and is essential for embryonic survival. These results suggest that GCNF regulates a novel and critical developmental pathway involved in normal anteroposterior development.

Morphology of the human thyroglossal tract: a histologic and macroscopic study in infants and children

The anatomic development of thyroglossal tract remnants is not understood at present. For analysis of morphology and growth patterns of thyroglossal tract remnants, we used histologic whole organ serial sections to determine developmental changes through the first years of life. Larynges of 58 infants and children ages 1 month to 13 years were obtained in whole organ serial step-sections in an axial plane. The slides were stained with hematoxylin and eosin, Alcian blue, and periodic acid-Schiff stains. Altogether, 3,247 histologic slices were examined. The resulting data were then correlated with the age and sex of the specimens. We found, in 24 cases (41.3%), remnants of the thyroglossal tract or ectopic thyroid tissue. In 4 specimens (16.6%), a complete thyroglossal tract could be observed that presented a ventral path in relation to the hyoid bone with no contact with the perichondrium of the cartilage. Hormonal activity of ectopic thyroid tissue was proven in 20 cases (34.5%). Thyroid follicles were located in 2 cases (3.5%) in the hyoid bone. The thyroglossal ducts revealed a modest tendency for a left-sided pathway, whereas thyroid follicles were located more on the right paramedian side. Morphometric data on the development and structure of the thyroglossal tract and the thyroid follicles during infancy and childhood are presented. The study provides quantitative data of clinical interest that elucidate the anatomy of thyroglossal tract remnants. In addition, our investigation supports Sistrunk's operative approach for avoiding recurrences in the treatment of thyroglossal duct cysts.

Role of the target in the pathfinding of facial visceral motor axons

Axon navigation depends, in part, on guidance cues emanating from the target. We have investigated the possible role of the target in the pathfinding of visceral motor axons to cranial parasympathetic ganglia. Mice homozygous for a tau-LacZ transgene targeted in the Phox2a locus lack the sphenopalatine ganglion, which is the normal target of visceral motor axons of the facial nerve. We found that in these mutants, facial visceral motor axon pathfinding was disrupted, and some axons were misrouted to an alternative parasympathetic ganglion. Moreover, the absence of correct facial visceral motor pathways was concomitant with defects in the pathfinding of rostrally-projecting sympathetic axons.

Ectopic adrenals in a sirenomelic fetus

A sirenomelic malformation was diagnosed in a fetus from the first pregnancy of a 25-year-old woman, and it was aborted at the 24th week of gestation. The fetus represented a sympus monopus. The head, organs of the neck, the thorax, and the upper part of abdominal cavity were normally formed. The kidneys, the ureters, the urinary bladder and the urethra were not developed. Adrenals of discoid shape and normal size were present in the normal position. The large bowel ended blindly in the sigmoid colon. Both testes were found in their normal position in the pelvis. Two symmetrical structures, resembling ovaries in shape and colour, were found near the testes. Histological examination established that these two organs were accessory (aberrant) adrenals.

Thyrotoxicosis in a patient with submandibular thyroid

Ectopic thyroid glands generally appear in the midline due to abnormal median migration; their presence lateral to the midline is rare. We report the case of a 42-year-old female who presented with symptoms of thyrotoxicosis and an expanding submandibular swelling. Tc-99m-sodium pertechnetate scanning showed thyroid tissue in the left submandibular region, while no thyroid tissue was seen in the normal site. The patient was treated with 10 mCi of 131I and subsequently became euthyroid. Literature review revealed seven cases of lateral aberrant thyroid tissue. The theories to explain lateral aberrant thyroid are presented.

Anterior patterning by synergistic activity of the early gastrula organizer and the anterior germ layer tissues of the mouse embryo

Fragments of the germ layer tissues isolated from the early-primitive-streak (early-streak) stage mouse embryos were tested for axis induction activity by transplantation to late-gastrula (late-streak to early-bud) stage host embryos. The posterior epiblast fragment that contains the early gastrula organizer was able to recruit the host tissues to form an ectopic axis. However, the most anterior neural gene that was expressed in the ectopic axis was Krox20 that marks parts of the hindbrain, but markers of the mid- and forebrain (Otx2 and En1) were not expressed. Anterior visceral endoderm or the anterior epiblast alone did not induce any ectopic neural tissue. However, when these two anterior germ layer tissues were transplanted together, they can induce the formation of ectopic host-derived neural tissues but these tissues rarely expressed anterior neural genes and did not show any organization of an ectopic axis. Therefore, although the anterior endoderm and epiblast together may display some inductive activity, they do not act like a classical organizer. Induction of the anterior neural genes in the ectopic axis was achieved only when a combination of the posterior epiblast fragment, anterior visceral endoderm and the anterior epiblast was transplanted to the host embryo. The formation of anterior neural structures therefore requires the synergistic interaction of the early gastrula organizer and anterior germ layer tissues.

[Human "pancreatic" bladder. Two case reports]

The aim of this study is to report two similar cases with an "accessory biliary duct" confluent to the main pancreatic duct. There was pancreatic juice inside the "gallbladder". There was no connection between "accessory biliary duct" and intra or extrahepatic biliary ducts. This anomalous junction of the "cystic duct" and the main pancreatic duct may be explained by embryology. These two cases could be the first human "pancreatic" bladders reported.

Malformations of cranial base structures and pituitary gland in prenatal Meckel syndrome

The sella turcica region, including the clivus and the pituitary gland, was studied histologically in five human fetuses with Meckel syndrome (MS). All cases had malformed sella turcica and malformed clivus with irregularly shaped notochordal remnants. We consider that these three characteristics are constant phenotypic traits in MS. The adenohypophysis was present in three cases. In one of these, ectopia of the gland occurred with adenopituitary tissue overlying the dorsum sella, and in another remnants were found in the pharyngeal submucosa. In two fetuses the neurohypophysis was not found. The findings in the region were compared to normal findings and to findings in trisomy 18, where cranial base structures radiographically appeared similar to those in MS. We conclude that in MS specific characteristics are found in the cranial base region and that radiographic analysis needs to be supplemented by histological analysis when studying this specific region.

Pharyngeal pituitary: development, malformation, and tumorigenesis

The development of the pharyngeal pituitary (PhP) in the fetal period was morphologically and, for the first time, immunohistochemically examined. PhP, found in every individual, begins its hormone production at the 17-18th week of gestation, that is, 4-8 weeks later than that of sellar pituitary (SP). Only 1 of 25 examined fetuses without any stigmata of developmental anomalies showed a residual pituitary fragment in the craniopharyngeal canal (craniopharyngeal pituitary, CPhP). An adult case of a rare clivus pituitary adenoma that we examined is demonstrated in discussing its relationship to PhP. Extracranial ectopic pituitary adenomas in the literature describe an exclusively sphenoid sinus/nasopharyngeal/clivus location of the tumor. Their location corresponded exactly with that of PhP, so that the origin of the tumors can be reasonably speculated as PhP, although another origin, e.g., CPhP, can not be excluded. A variety of malformations of PhP, although very rare, have been described for the fist time during the systemic examination of 16 fetuses with different cranioneural malformations, such as agenesis, unseparated PhP from SP (pharyngosellar pituitary), fragmentation, and residual pituitary tissue in the open craniopharyngeal canal. However, developmental anomaly of PhP was not specifically associated with cranioneural malformations except in cases of chromosomal aberrations. The hormone production in PhP in malformation cases tended to be retarded. Absence of SP was recorded in 50% of anencephalics in the literature; however, PhP was identified in all anencephalics in our series, independent of the existence of SP. This supports the opinion that agenesis of SP in anencephalics seems to be false information.

In utero brain lesions in SIDS

Serial examination of the cerebral hemispheres of 20 sudden infant death syndrome victims revealed high incidence of leukomalacia (40%), leptomeningeal glioneuronal heterotopias (70%) at the base of the cerebrum, and astrogliosis (65%) in the white matter and medulla reticular formation compared with 20 age-matched controls. These results suggest that an antepartum insult may become an important predisposing risk factor in some patients for sudden infant death syndrome.

Nephrogenic rests, nephroblastomatosis, and associated lesions of the kidney

The fetal kidney is formed by the development of nephrons from fetal metanephric blastema surrounding the ureteric bud. The fetal renal tissue matures into normal renal parenchyma during gestation, but, occasionally, fetal tissue persists into infancy as microscopic foci called nephrogenic rests. Nephrogenic rests are found in approximately 1% of infant kidneys at autopsy. Nephrogenic rests are associated with an increased risk of Wilms tumor, and it is theorized that nephrogenic rests undergo neoplastic change into Wilms tumor. Fortunately, this transformation occurs in less than 1% of young children with nephrogenic rests. Nephrogenic rests are associated with many syndromes, including Beckwith-Wiedemann syndrome, hemihypertrophy, and sporadic aniridia. Children with identifiable syndromes, once diagnosed, should be screened for the development of Wilms tumor. Nephrogenic rests are associated with other lesions such as multilocular cystic nephroma and multicystic dysplasia, usually without malignant complications.

Unilateral suprainguinal ectopic scrotum: the role of the gubernaculum in the formation of an ectopic scrotum

A rare case of ectopic scrotum is described together with a review of the literature and a discussion of the embryological role of the gubernaculum in the formation and location of normal and ectopic scrota. We identified 16 reported cases of a suprainguinal ectopic scrotum, 4 cases of a femoral ectopic scrotum, 26 cases of penoscrotal transposition, and 19 cases of a perineal (accessory) scrotum. Although the gubernaculum is a prerequisite for the ultimate location of both the testis and scrotum, its role is complicated by the subsequent differential growth of the labioscrotal folds in which the gubernaculum is stabilized. If this interaction is disturbed, the result may be a suprainguinal ectopia, penoscrotal transposition or a perineal scrotum. A femoral ectopic scrotum, unlike the above, is the result of an aberrant gubernacular stabilization. While the etiology of these malformations is likely to be multifactorial, the existence of an inbred strain of rats characterized by a high incidence of an ectopic scrotum suggests a genetic component to this anomaly.

[Lingual osteoma. Apropos of a case]

The authors present a case of osteoma of the tongue. This tumor was discovered without any functional symptom. Surgical resection with histological examination gives the diagnostic. This choristoma is rare, benign and clinically poor. Osteoma of the tongue is a heterotopic bone tissue and his main differential diagnosis are lingual thyroid and thyroglossal cyst. There are several opinions concerning the histogenesis of this choristoma, but an embryological anomaly is probable. Surgical removal of the tumor is curative, without any reported local recurrence.

Unilateral inguinal ectopic scrotum and imperforate anus: a case report

A case of an ectopic scrotum located in the right inguinal area is described. The left hemiscrotum was in normal location, and each hemiscrotum contained testis. The boy also had an infralevator-type anorectal malformation. Initially, anoplasty was performed, and scrotal reconstruction was carried out 1 month later. The authors also reviewed the embryological explanation of ectopic scrotum in the literature.

Supernumerary breast tissue: a case of pseudomamma on the face

Supernumerary breast tissue usually develops along the milk line. But occasionally, it may be seen outside the milk line. In this article, the authors describe a case of pseudomamma on the face, one of the rarest locations for supernumerary breast tissue. The lesion was removed for cosmetic reasons. There was no associated anomaly.

Transverse testicular ectopia with persistent müllerian duct syndrome

Transverse testicular ectopia is rarely associated with persistent müllerian duct syndrome. The ninth pediatric case of transverse testicular ectopia with persistent müllerian duct syndrome is reported. The clinical and operative findings and treatment are discussed. The importance of abdominal exploration in the presence of two gonads in one inguinal side and the avoidance of dissection of müllerian structures has been stressed.

Grey matter heterotopia: an unusual association of intractable epilepsy

Heterotopic grey matter is an abnormality of neuronal migration that has been reported in association with refractory epilepsy. In this study we reviewed the magnetic resonance (MR) imaging records of all patients undergoing MR scanning for evaluation of intractable epilepsy and identified sixteen patients who had grey matter heterotopia. The distribution of the grey matter heterotopia was periventricular in 9 patients, laminar in 3 and was in a "band" form in 4 patients. Congenital anomalies associated with grey matter heterotopia in this study included polymicrogyria in one patient and absence of the corpus callosum in 2 patients. Grey matter heterotopia is an important MR finding in patients with intractable epilepsy.

Behavioral consequences of abnormal cortical development: insights into developmental disabilities

Cerebral cortical development occurs in precisely-timed stages that can be divided into neurogenesis, neuronal migration and neuronal differentiation. These events occur during discrete time windows that span the late prenatal and early postnatal periods in both rodents and primates, including humans. Insults at particular developmental stages can lead to distinctive cortical abnormalities including cortical hypoplasia (reduced cell number), cortical ectopias (abnormalities in migration) and cortical dysplasias (abnormalities in the shapes or numbers of dendrites). In this review, we examine some of the most extensively-studied animal models of disrupted stages of cortical development and we compare long-term anatomical, neurochemical, and behavior abnormalities in these models. The behavioral abnormalities in these models range from alterations in simple motor behaviors to food hoarding and maternal behaviors as well as cognitive behaviors. Although we examine concisely animal models of cortical hypoplasia and cortical ectopias, we focus here on developmental manipulations that affect cortical differentiation, particularly, those that interrupt the normal ontogeny of the neurotransmitter-defined cortical afferent systems: norepinephrine, serotonin, dopamine and acetylcholine. All of these afferents presumably play a critical role in the maturation of their cortical targets; the timing of the afferents' entry into the cortex and their effects on their cortical targets, however, are different. We, therefore, compare the specific anatomical, neurochemical and behavioral effects of manipulations of the different cortical afferents. Because of the considerable evidence that cortical development proceeds differently in the two sexes, when data are available, we address whether perinatal insults differentially affect the sexes. Finally, we discuss how these developmental studies provide insights into cellular and neurochemical correlates of behavioral functional abnormalities and the relevance of these data to understanding developmental disabilities in humans.

Neuronal heterotopias in the developing cerebral cortex produced by neurotrophin-4

The marginal zone (MZ) of embryonic neocortex is crucial to its normal development. We report that neurotrophin-4 (but not NT3 or NGF), applied to embryonic rodent cortex in vitro or in vivo, produces heterotopic accumulations of neurons in the MZ. Although heterotopia production is TrkB mediated, BDNF is >10-fold less effective than NT4. Heterotopic neurons have the same birth date and phenotype as normal MZ neurons; they are not the result of NT4-induced proliferation or rescue from apoptosis. We suggest that NT4 causes excess neurons to migrate into the MZ and thus may play a role in normal MZ formation as well as in the pathogenesis of certain human cortical dysplasias.

Pathologic intrathyroidal parathyroid glands

BACKGROUND

Parathyroid glands originate from the third and fourth branchial pouches and migrate caudally to their final positions. Aberrations during migration result in anomalous locations. Intrathyroidal location is not common.

METHODS

We reviewed cervical explorations performed from 1974 to 1993 in hyperparathyroidism patients.

RESULTS

We found pathological intrathyroidal glands in six patients. Three patients had adenomas (left superior, left inferior and right inferior glands). The hyperplastic glands were left inferior in one patient and right inferior in the remaining two. Intraoperative diagnosis was made in three cases in which palpation of the thyroid gland showed a nodule that was suspected to be the parathyroid missing gland. In three patients it was a finding in thyroidectomy or hemithyroidectomy specimens, two of them with associated thyroid nodular disease.

CONCLUSIONS

Ipsilateral thyroidotomy on the side of a palpable thyroid mass or blind hemithyroidectomy are justified if a presumably pathological intrathyroidal gland is suspected, when all other sites in the neck have been excluded.

[Ectopic thyroid gland in the submandibular region]

A case of an ectopic thyroid gland in the submandibular region is presented. The embryological aspects are discussed.