The developmental anomalies of the lacrimal passage are interesting, because they are rare. The primordium of the lacrimal passage which is derived from surface ectoderm become situated in the groove between the lateral nasal and maxillary process at about 10-mm (5 weeks) stage. At 15-mm (6 weeks) stage it is free from surface ectoderm and by budding from its upper end maps out the canaliculi and puncta. Anomalies which may develop thus follow the forms of the embryological development, so that the sac and canaliculi may fail to bud off from the surface ectoderm cells, the canaliculi may run in the wrong direction, they may eventually fail to canalize, or they may be extra rods of cells budding off tbe original rod thus forming supernumeraly canaliculi and puncta. Two cases of developmental anomalies of the lacrimal passage, one has no visible puncta and the other has double puncta of both lower lids, were presented.
Ectoderm

No abstract available.
Ectoderm*

No abstract available.
Ectoderm*

No abstract available.
Ectoderm* ; Ectodermal Dysplasia*

No abstract available.
Ectoderm* ; Ectodermal Dysplasia* ; Prosthodontics*

Absence or atresia of the canaliculus and punctum is rare. The primordium of the lacrimal passage which is derived from surface ectoderm is developed along the line of the cleft between the lateral nasal and the maxillary processes at about 10 mm. (5th week) embryo. At 15 mm. (6th week) embryo, it becomes detached from the surface ectoderm to form an irregular solid rod of cells; the epithelial cord thus formed represents the rudiments of the lacrimal passages. By bud-like cutgrowths from the upper extremity of the uppermost rod of cells, these are rudiments of the lacrimal canaliculi and they reach the epithelium of the lid margins at the 35 mm. embryo. During the 3rd month the central cells of the solid rod begin to disintegrate; the originally solid naso-lacrimal passages thus become canalized. Although the lumina of the canaliculi become patent during the 4th month, the lacrimal puncta do not open onto the lid margins until just before the lids separate during the 7th month. The three main types of developmental anomaly affecting the passages are gross changes; due to failure in the regular fusing of the nasal and maxillary processes, samller changes: due to an abnormal course being followed by the budding cells, and failures in canalization resulting in atresia. Authors presented 2 cases of absence of puncta combined with atresia of canaliculi which send to be resulted from failure in canalization.
Ectoderm ; Embryonic Structures ; Epithelium ; Upper Extremity

Choristoma is a congenital abnormal growth of tissue with components which are not characteristic of the location. Most choristomas often affect tissues of one germinal layer, mainly ectodermal layer, but complex choristoma contains two or more choristomatous tissues(ectodermal, mesodermal and rarely entodermal tissue) except lacking pilosebaceous apparatus. We experienced a case of large bilateral saccular complex choristomas including scleral and episcleral cartilage in the upper part of cornea, limbus and sclera, which was confirmed histopathologically.
Cartilage* ; Choristoma* ; Cornea ; Ectoderm ; Mesoderm ; Sclera

Congenital Ectodermal dysplasia is known to be rare, recently we experienced one case of congenital ectodermal dysplasia of hydrotic tipe in newborn infant due to autosomal dominance. Review of Literatvre was done briefly.
Ectoderm* ; Ectodermal Dysplasia* ; Humans ; Infant, Newborn

Neurilemoma(schwannoma, neurinoma, Schwann's cell tumor) is a relatively uncommon, slowly growing lesion that usually has been present for a considerable time before diagnosis and treatment are requested. The site of origin is believed to be the ectodermal Schwann cells of the nerve sheath. An interesting variant, known as the ancient neurilemoma, has been reported by Eversole and others. They suggest that the histologic feature that typify this tumor result from degenerative changes which occur as a classic neurilemoma ages. We have experienced a case of schwannoma arising on the nasal tip of a 27 years old man and discussed with brief current literatures review.
Adult ; Diagnosis ; Ectoderm ; Humans ; Neurilemmoma* ; Schwann Cells

Median raphe cyst is not a cornmon disease and represents a defect in the embryologic development of male genitalia. It occurs most commonly near the glans penis, but may occur anywhere from the urethral meatus to the anus, and is lined by entodermal or ectodermal epithelium. Surgical excision is the treatment of choice. Recently we observed a 29-year-old male patient who had had a typical median raphe cyst since childhood on the ventral aspect of the glans penis. On histological examination, the cyst was lined by stratified columnar epithelium varied from four to eight cells in thickness.
Adult ; Anal Canal ; Ectoderm ; Epithelium ; Genitalia, Male ; Humans ; Male ; Penis*