Evolution of epidermoid cyst into dermoid cyst: Embryological explanation and radiological-pathological correlation.

Intracranial dermoid and epidermoid cysts are usually considered to be two different entities in the radiological and surgical literature. Epidermoid cysts are classically off midline in location, isointense to cerebrospinal fluid on T1 and T2-weighted images and have restricted diffusion, whereas dermoid cysts are classically midline in location, have T1-hyperintense regions due to the presence of fat and show facilitated diffusion. We report a case of radiological epidermoid cyst in baseline imaging, which evolved into a radiological dermoid cyst over time, and explain this unique occurrence with a review of the embryology and histopathogenesis of these cysts.

Congenital cystic neck masses: embryology and imaging appearances, with clinicopathological correlation.

Congenital cystic masses of the neck are uncommon and can present in any age group. Diagnosis of these lesions can be sometimes challenging. Many of these have characteristic locations and imaging findings. The most common of all congenital cystic neck masses is the thyroglossal duct cyst. The other congenital cystic neck masses are branchial cleft cyst, cystic hygroma (lymphangioma), cervical thymic and bronchogenic cysts, and the floor of the mouth lesions including dermoid and epidermoid cysts. In this review, we illustrate the common congenital cystic neck masses including embryology, clinical findings, imaging features, and histopathological findings.

Adult nasal dermoid sinus cyst.

Midline congenital nasal lesions are rarely encountered in adults. We present the case of a 31-year-old man with a nasal dermoid sinus cyst who presented with a nasal dorsal abscess. We review the embryology of nasal dermoid sinus cysts, and we discuss their presentation, evaluation, and management in adults.

Congenital neck masses.

Congenital neck lesions reflect abnormal embryogenesis in head and neck development. A thorough knowledge of embryology and anatomy is critical in the diagnosis and treatment of these lesions. The appropriate diagnosis of these lesions is necessary to provide appropriate treatment and long-term follow up, because some of these lesions may undergo malignant transformation or be harbingers of malignant disease.

Intramedullary dermoid in a low lying conus tethered by a fatty filum - embryological implications.

Intramedullary dermoids arising within the conus medullaris are rare. We report a rare association of an intramedullary dermoid cyst located in a low lying conus tethered by a thickened, fatty filum terminale and discuss the embryological implications of this association.

Congenital nasal malformations.

The nose is a prominent feature of the human face. Congenital malformations of the nose, whether functional or anatomic, affect the physiologic and psychologic wellness of children who have these anomalies. Congenital nasal abnormalities may be overt or subtle and can occasionally cause life-threatening emergencies at birth. A discussion of nasal embryology and development provides the basis for the discussion of some of the important congenital abnormalities seen in clinical practice. The final portion of the article is devoted to several of the more common syndromes in which nasal abnormalities are encountered.

Craniofacial dermoids: an embryological theory unifying nasal dermoid sinus cysts.

OBJECTIVE: The nasal dermoid sinus cyst (NDSC) is an uncommon congenital lesion presenting as a large panel of midline craniofacial anomalies. The objective of this study was to review and reanalyze embryological hypotheses concerning NDSCs and to propose an embryological theory unifying the various anatomical characteristics of these lesions. The first case of frontal localization of a NDSC extending within the diploetic bone in a 9-month-old boy, presenting as a median frontal fistula with recurrent frontal swelling, 6 months after a mild frontal trauma is presented. RESULTS: Complete surgical removal was performed, and there was no evidence of either persistent or recurrent disease 2 years after his surgery. The embryological and anatomical origins of NDSCs are reviewed. This article reexamines and discusses major embryological theories on NDSC pathogenesis and proposes to refute the "prenasal space" theory of Grunwald and rehabilitate a forgotten embryological hypothesis, which unifies the main various clinical presentations of NDSCs.

Congenital dermoid cyst of the tongue.

True dermoid cysts of the oral cavity are rare, usually presenting as midline swellings in the floor of the mouth and occasionally elsewhere in the oral cavity. This report describes the diagnosis and management of a congenital dermoid cyst of the lateral aspect of the body of the tongue in a 10-year-old girl. The theories of the pathogenesis of this cyst during embryogenesis of the tongue are also reviewed.

Pharyngeal dermoids ("hairy polyps") as accessory auricles.

The purpose of this study is to clarify the origin and nature of so-called hairy polyps or dermoids of the pharynx, which are often thought to be a variant of pharyngeal teratoma. For this purpose, a case is reported of a dermoid polyp involving the middle ear of an infant, the features of multiple examples of pharyngeal dermoid polyps and teratomas received for consultation by the Armed Forces Institute of Pathology are examined, and selected pertinent reports from the literature are reviewed. All three means are used to support the conclusion that these lesions are choristomatous developmental anomalies arising from the first branchial cleft area and that they essentially represent heterotopic accessory "ears" (auricles) without the growth potential of a teratoma.

Cerebellar dermoid tumor and occipital meningocele in a monozygotic twin: clues to the embryogenesis of craniospinal dysraphism.

A case of monochorionic/monoamnionic twin with discordant occipital developmental malformations is presented. One female twin appeared to have an occipital meningocele with cerebellar aplasia and died immediately after birth. The other twin presented with signs and symptoms of raised intracranial pressure at the age of 7 months. Severe hydrocephalus was present due to an infected intracerebellar dermoid tumor with a contiguous occipital dermal sinus. The clinical and pathological characteristics are described and the different theories concerning twinning, embryogenesis, and dysmorphology in relation to neural tube defects are discussed. Analysis of the features of these monozygotic twins indicates that a meningocele is not a post-neurulation disorder but results from deficient neurulation, probably due to mesodermal insufficiency.

Dermoids and dermal sinus tracts of the spine.

The evaluation of a child with a midline dimple or pit is one of the most common referrals to a pediatric neurosurgeon. Regardless of their depth, those below the top of the intergluteal crease end blindly and never extend intraspinally. Families can be reassured there is no infection or mechanical risk to the developing nervous system. A high index of suspicion must be maintained for all dimples above the intergluteal fold despite a normal examination or neuroradiologic studies. The midline must be carefully inspected when a child of any age suffers meningitis, especially when an unusual organism is cultured. Conservative management of dermal sinuses is not justified, and these lesions should be electively resected at the time of diagnosis. Dermal sinuses and inclusion tumors may lead to spinal cord tethering and progressive neurologic deterioration. Surgery in advance of deficits maintains normal neurologic function, and children can develop unencumbered by infection, motor, or bladder paralysis.

[Dermoid cyst in the fourth ventricle associated with Klippel-Feil syndrome].

Dermoid cysts in the central nervous system are often associated with various congenital disorders, especially dermal sinus and spina bifida. We report a case of dermoid cyst in the fourth ventricle associated with Klippel-Feil syndrome. A 47-year-old man with a long history of headache had been known to have a cystic lesion in the posterior fossa for 12 years. When he was referred to our hospital with complaints of transient tetraparesis, he showed bilateral cerebellar ataxia and minimal left hemiparesis. Furthermore, he was noted to have a webbed neck with a low hairline and facial asymmetry. CT and MRI showed multiple cerebral infarctions as well as a mass lesion in the posterior fossa. Cervical roentgenogram showed a fusion of C 2 and C 3 vertebrae. The tumor was totally removed via a suboccipital approach, and the diagnosis was a dermoid cyst. The present patient had not only dermoid cyst and Klippel-Feil syndrome but also hypertrophy of the zygomatic bone. The pathogenesis of the Klippel-Feil syndrome is presumed to be an intrauterine defect, with a failure of segmentation of mesodermal somites. The zygomatic bone is also derived from the mesoderm somites at early fourth week, too. From these points of view, the disturbance in the mesoderm before the fourth week of gestation might have played an important role in causing a dermoid cyst.

[Dermoid cyst of the scalp. Apropos of a case]. / Kyste dermoïde du cuir chevelu. A propos d'un cas.

A subgaleal dermoid cyst of a 32 years old white adult is reported. The lesion appeared at the age of several years and ten regularly. Clinical examination, complementary exams as well as the result of the operation are reported. Embryology, histological classification and the main clinical, laboratory and histological characteristics of such lesions are defined by the review of the literature. Subgaleal dermoid cyst is rare in childhood and exceptionally occurs in adults. Only six cases of subgaleal dermoid cyst of adult are mentioned in the literature. Most of the time, the lesion is situated on the anterior fontanelle. The treatment is surgical and the prognosis is excellent.

[Dermoid of the cornea. Report of 2 cases of Ida Mann's 2nd type]. / Dermoïdes de la cornée. A propos de deux observations du 2e degré de Ida Mann.

At the opposite of epibulbar dermoids (which are isolated or combined), dermoids of IDA MANN's second type are uncommon. The two cases reported had a big size and covered almost the cornea, without damage on the descemet's membrane, the endothelium and the other eyeball structures. This lesion is classified by the W.H.O. among choristomas. It's made of skin recovering fat which includes in different figures, hair follicle, eccrine and sweat glands. Total excision is the best treatment, but couls become complicated by cornea perforation. It could be followed in some cases by keratoplasty. Amblyopia could go with this malformation.

Unilateral athelia with a subcutaneous dermoid cyst.

A case of unilateral athelia with a subcutaneous dermoid cyst in the area in question is reported. The histologic features of the cyst wall suggest that it is derived from a base in the nipple-areola complex. Dozens of cases of congenital absence of the breast have been reported, some of them associated with congenital anhidrotic ectodermal dysplasia, others with additional musculoskeletal abnormalities, and still others normal in other respects. But to our knowledge, the combination of athelia and corresponding subcutaneous dermoid cyst has not been reported.

Dysontogenetic neoplasms of the thyroid gland in infancy: two case reports.

Two rare cases of benign dysontogenetic neoplasms of the thyroid gland in pediatric age are presented, which were observed at the E.N.T. department of the Bambino Gesù Hospital of Rome, and successfully operated. The first case turned out to be a dysembryoma, classified as monodermic because of its origin from derivatives of only one germinal layer, the entoderm. The second case, a teratoma, presented a high seric concentration of AFP as the consequence of the synthetic activity of the share of embryonal epatic tissue present in the neoformation. Criteria to distinguish thyroid from cervical teratomata and to classify the different types of dysontogenetic neoplasms are discussed. The usual clinical and pathological manifestations of teratomas of the neck in infancy are mentioned. The necessity of a prompt surgical removal and of pre- and postoperative thyroid function studies is mentioned.