Large and especially giant congenital nevi are at higher risk for malignancy degeneration into melanoma. Because of the premalignant potential, it is an acceptable clinical practice to remove congenital nevi electively in all patients and relieve the nevocytic overload.

If a patient displays congenital melanocytic nevi or giant congenital melanocytic nevi, the criteria for diagnosis of neurocutaneous melanosis is as follows:

- Melanocytic deposits exist within the central nervous system that are either malignant or benign

- The cutaneous lesions, giant or otherwise, are not malignant

This criteria is typically validated through biopsy of the cutaneous lesions and imaging of the central nervous system. It is important to establish that the cutaneous lesions are benign. If not, then the melanocytic deposits in the central nervous system may be the result of metastasis of cutaneous melanoma and not neurocutaneous melanosis.

Imaging has been shown to be the only reliable detection method for the presence of neurocutaneous melanosis that can be performed in living patients. Currently, the preferred imaging modality for diagnosis of neurocutaneous melanosis is Magnetic Resonance Imaging, although ultrasound is another viable option. The signal due melanin deposits in the leptomeninges typical of neurocutaneous melanosis can be easily detected in MRI scans of patients under four months old. In patients above this age, there is some suggestion that normal brain myelination may partially obscure these signals.

As most patients with neurocutaneous melanosis are asymptomatic, those who are diagnosed through MR imaging are not guarantied to develop symptoms. Those diagnosed who did not develop symptoms ranged from 10% to 68%. This wide range is most likely due to the large number of asymptomatic, undiagnosed patients with neurocutaneous melanosis.

Benign congenital nevi can have histological characteristics resembling melanomas, often breaking most if not all of the ABCDE rules. Dermatoscopic findings of the smaller forms of benign congenital nevi can aid in their differentiation from other pigmented neoplasms.

Microscopically, congenital melanocytic nevi appear similar to acquired nevi with two notable exceptions. For the congenital nevus, the neval cells are found deeper into the dermis. Also, the deeper nevus cells can be found along with neurovascular bundles, with both surrounding hair follicles, sebaceous glands, and subcutaneous fat. Such annexes and the hypodermis can also be hypoplasic or, conversely, present aspects of hamartoma.

The diagnosis is made clinically, and usually this is clear cut if the lesion is associated with the flange of a denture. Tissue biopsy is not usually indicated before removal of the lesion, since the excises surgical specimen is usually sent for histopathologic examination and the diagnosis is confirmed retrospectively. Rarely, incisional biopsy may be indicated to rule out neoplasia, e.g. in the presence of suspicious ulceration. The appearance may also be confused with pyogenic granuloma.

The excessive tissue is composed of cellular, inflamed fibrous connective tissue. The appearance of an epulis fissuratum microscopically is an overgrowth of cells from the fibrous connective tissue. The epithelial cells are usually hyperkeratotic and irregular, hyperplastic rete ridges are often seen.

The majority of patients with neurocutaneous melanosis are asymptomatic and therefore have a good prognosis with few complications. Most are not diagnosed, so definitive data in not available. For symptomatic patients, the prognosis is far worse. In patients without the presence of melanoma, more than 50% die within 3 years of displaying symptoms. While those with malignancy have a mortality rate of 77% with most patients displaying symptoms before the age of 2.

The presence of a Dandy-Walker malformation along with neurocutaneous melanosis, as occurs in 10% of symptomatic patients, further deteriorates prognosis. The median survival time for these patients is 6.5 months after becoming symptomatic.

If the causative factor persists, tissue will become more fibrous over time.

Epulis (; plural "epulides") is any tumor like enlargement (i.e. lump) situated on the gingival or alveolar mucosa. The word literally means "(growth) on the gingiva", and describes only the location of the mass and has no further implications on the nature of the lesion. There are three types: fibromatous, ossifying and acanthomatous. The related term parulis (commonly called a gumboil) refers to a mass of inflamed granulation tissue at the opening of a draining sinus on the alveolus over (or near to) the root of an infected tooth. Another closely related term is gingival enlargement, which tends to be used where the enlargement is more generalized over the whole gingiva rather than a localized mass.

Lip pits are harmless and do not usually require any treatment, although in some reported cases surgical excision has been used.

An epulis granulomatosa is a granuloma which grows from an extraction socket (the hole left after a tooth has been removed), and as such can be considered to be a complication of healing after oral surgery.

Courses of treatment typically include the following:

- Draining the pus once awhile as it can build up a strong odor

- Antibiotics when infection occurs.

- Surgical excision is indicated with recurrent fistular infections, preferably after significant healing of the infection. In case of a persistent infection, infection drainage is performed during the excision operation. The operation is generally performed by an appropriately trained specialist surgeon e.g. an otolaryngologist or a specialist General Surgeon.

- The fistula can be excised as a cosmetic operation even though no infection appeared. The procedure is considered an elective operation in the absence of any associated complications.

Fibrosarcoma occurs most frequently in the mouth in dogs . The tumor is locally invasive, and often recurs following surgery . Radiation therapy and chemotherapy are also used in treatment. Fibrosarcoma is also a rare bone tumor in dogs.

In cats, fibrosarcoma occurs on the skin. It is also the most common vaccine-associated sarcoma. In 2014, Merial launched Oncept IL-2 in Europe for the management of such feline fibrosarcomas.

Treatment can be medical or surgical. Laser endoscopic treatment is often preferred. Voice therapy is sometimes necessary.

They are divided into three types based on their location:

- commissural pits, which are small pits near the labial commissure of the mouth,

- a pit in the upper lip, in which case it may be called a midline sinus of the upper lip, and

- pits in the lower lip, in which case it may be called a congenital sinus of the lower lip.

In some cases commissural pits have been reported in combination with preauricaluar pits, which are near the ear.

For most cases the diagnosis for congenital amputation is not made until the infant is born. One procedure that is helpful in determining this condition in an infant is an ultrasound examination of a fetus when still in the mother's abdomen as it can reveal the absence of a limb. However, since ultrasounds are routine they may not pick up all the signs of some of the more subtle birth defects.

The most popular method of treatment for congenital amputation is having the child be fit for a prosthesis which can lead to normal development, so the muscles don't atrophy. If there is congenital amputation of the fingers, plastic surgery can be performed by using the big toe or second toes in place of the missing fingers of the hand.

In rare cases of amniotic banding syndrome, if diagnosed "in utero", fetal surgery may be considered to save a limb which is in danger of amputation.

Studies suggest that prenatal care for mothers during their pregnancies can prevent congenital amputation. Knowing environmental and genetic risks is also important. Heavy exposure to chemicals, smoking, alcohol, poor diet, or engaging in any other teratogenic activities while pregnant can increase the risk of having a child born with a congenital amputation. Folic acid is a multivitamin that has been found to reduce birth defects.

Prosthetic replacement of missing teeth is possible using dental implant technology or dentures. This treatment can be successful in giving patients with anodontia a more aesthetically pleasing appearance. The use of an implant prosthesis in the lower jaw could be recommended for younger patients as it is shown to significantly improve the craniofacial growth, social development and self-image. The study associated with this evidence worked with individuals who had ectodermal dysplasia of varying age groups of up to 11, 11 to 18 and more than 18 years. It was noted that the risk of implant failure was significantly higher in patients younger than 18 years, but there is significant reason to use this methodology of treatment in those older. Overall the use of an implant-prosthesis has a considerable functional, aesthetic and psychological advantage when compared to a conventional denture, in the patients.

Neurocristopathy is a diverse class of pathologies that may arise from defects in the development of tissues containing cells commonly derived from the embryonic neural crest cell lineage. The term was coined by Robert P. Bolande in 1974.

Accepted examples are piebaldism, Waardenburg syndrome, Hirschsprung disease, Ondine's curse (congenital central hypoventilation syndrome), pheochromocytoma, paraganglioma, Merkel cell carcinoma, multiple endocrine neoplasia, neurofibromatosis type I, CHARGE syndrome, familial dysautonomia, DiGeorge syndrome, Axenfeld-Rieger syndrome, Goldenhar syndrome (a.k.a. hemifacial microsomia), craniofrontonasal syndrome, congenital melanocytic nevus, melanoma, and certain congenital heart defects of the outflow tract, in particular.

Multiple sclerosis has also been suggested as being neurocristopathic in origin.

The usefulness of the definition resides in its ability to refer to a potentially common etiological factor for certain neoplasms and/or congenital malformation associations that are otherwise difficult to group with other means of nosology.

Congenital cysts of the larynx with incidence of about 1.8 in 100,000 newborns.

Laryngeal cysts form 4% of all laryngeal tumors or about 5% of benign laryngeal lesions. Prevalence is about equal between the sexes.

Ancillary testing for fibrosarcoma includes IHC, where vimentin is positive, cytokeratin and S100 are negative, and actin is variable.

Occasionally a preauricular sinus or cyst can become infected.

Most preauricular sinuses are asymptomatic, and remain untreated unless they become infected too often. Preauricular sinuses can be excised with surgery which, because of their close proximity to the facial nerve, is performed by an appropriately trained, experienced surgeon (e.g. a specialist General Surgeon, a Plastic Surgeon, an otolaryngologist (Ear, Nose, Throat surgeon) or an Oral and Maxillofacial Surgeon).

Aplasia cutis congenita (ACC) is a rare disorder characterized by congenital absence of skin. Frieden classified ACC in 1986 into 9 groups on the basis of location of the lesions and associated congenital anomalies. The scalp is the most commonly involved area with lesser involvement of trunk and extremities. Frieden classified ACC with fetus papyraceus as type 5. This type presents as truncal ACC with symmetrical absence of skin in stellate or butterfly pattern with or without involvement of proximal limbs.]It is the most common congenital cicatricial alopecia, and is a congenital focal absence of epidermis with or without evidence of other layers of the skin.

The exact etiology of ACC is still unclear but intrauterine infection by varicella or herpes virus, drugs such as methimazole, misoprostol, valproate, cocaine, marijuana etc., fetus papyraceus, feto-fetal transfusion, vascular coagulation defects, amniotic membrane adherence, abnormal elastic fiber biomechanical forces and trauma are implicated. It can be associated with Johanson-Blizzard syndrome, Adams-Oliver syndrome, trisomy 13, and Wolf-Hirschhorn syndrome.

It can also seen with exposure to methimazole and carbimazole in utero. This dermatological manifestation has been linked to Peptidase D haploinsufficiency and a deletion in Chromosome 19.

This condition has been linked to mutations in the ribosomal GTPase BMS1 gene.

In dentistry, anodontia, also called anodontia vera, is a rare genetic disorder characterized by the congenital absence of all primary or permanent teeth. It is associated with the group of skin and nerve syndromes called the ectodermal dysplasias. Anodontia is usually part of a syndrome and seldom occurs as an isolated entity.

Congenital absence of permanent teeth can present as hypodontia, usually missing 1 or 2 permanent teeth, or oligodontia that is the congenital absence of 6 or more teeth. Congenital absence of all wisdom teeth, or third molars, is relatively common. Anodontia is the congenital absence of teeth and can occur in some or all teeth (partial anodontia or hypodontia), involve two dentitions or only teeth of the permanent dentition (Dorland's 1998). Approximately 1% of the population suffers from oligodontia. Many denominations are attributed to this anomaly: partial anodontia, hypodontia, oligodontia, the congenital absence, anodontia, bilateral aplasia. Anodontia being the term used in controlled vocabulary Medical Subject Headings (MeSH) from MEDLINE which was developed by the United States National Library of Medicine. The congenital absence of at least one permanent tooth is the most common dental anomaly and may contribute to masticator dysfunction, speech impairment, aesthetic problems, and malocclusion (Shapiro and Farrington 1983). Absence of lateral incisors represents a major stereotype. Individuals with this condition are perceived as socially most aggressive compared with people without anodontia (Shaw 1981).

A low socioeconomic status in a deprived neighborhood may include exposure to “environmental stressors and risk factors.” Socioeconomic inequalities are commonly measured by the Cartairs-Morris score, Index of Multiple Deprivation, Townsend deprivation index, and the Jarman score. The Jarman score, for example, considers “unemployment, overcrowding, single parents, under-fives, elderly living alone, ethnicity, low social class and residential mobility.” In Vos’ meta-analysis these indices are used to view the effect of low SES neighborhoods on maternal health. In the meta-analysis, data from individual studies were collected from 1985 up until 2008. Vos concludes that a correlation exists between prenatal adversities and deprived neighborhoods. Other studies have shown that low SES is closely associated with the development of the fetus in utero and growth retardation. Studies also suggest that children born in low SES families are “likely to be born prematurely, at low birth weight, or with asphyxia, a birth defect, a disability, fetal alcohol syndrome, or AIDS.” Bradley and Corwyn also suggest that congenital disorders arise from the mother’s lack of nutrition, a poor lifestyle, maternal substance abuse and “living in a neighborhood that contains hazards affecting fetal development (toxic waste dumps).” In a meta-analysis that viewed how inequalities influenced maternal health, it was suggested that deprived neighborhoods often promoted behaviors such as smoking, drug and alcohol use. After controlling for socioeconomic factors and ethnicity, several individual studies demonstrated an association with outcomes such as perinatal mortality and preterm birth.

A 2007 study followed 112 individuals for a mean of 12 years (mean age 25.3, range 12–71). No patient died during follow-up, but several required medical interventions. The mean final heights were 167 and 153 cm for men and women, respectively, which is approximately 2 standard deviations below normal.