Gingival cyst (or dental lamina cyst) is a type of cysts of the jaws that originates from the dental lamina and is found in the mouth parts. It is a superficial cyst in the alveolar mucosa. It can be seen inside the mouth as small and whistish bulge. Depending on the ages in which they develop, the cysts are classsfied into gingival cyst of newborn (or infant) and gingival cyst of adult. Structurally, the cyst is lined by thin epithelium and shows a lumen usually filled with desquamated keratin, occasionally containing inflammatory cells. The nodes are formes as a result of cystic degeneration of epithelial rests of the dental lamina (called the rests of Serres).

Gingival cyst was first described by a Czech physician Alois Epstein in 1880. In 1886, a German physician Heinrich Bohn described another type of cyst. Alfred Fromm introduced the classification of gingival cysts in 1967. According to him, gingival cysts of newborns can be further classsified based on their specific origin of the tissues as Epstein’s pearls, Bohn’s nodules and dental lamina cysts.

Gingival cyst of adult is a rare condition. The incidence is less than 0.5%. It is formed from the rests of dental lamina. It is found in the soft tissues on the buccal and labial portions of the jaw. It usually occurs on the facial gingiva as a single small flesh colored swelling, sometimes with a bluish hue due to the cystic fluid. Sometimes, it may occur in cluster, either unilaterally or bilaterally or on the lingual surface of the alveolar process. It is most commonly seen in the canine and premolar regions of the mandible, and are sometimes confused with lateral periodontal cysts. It is not normally problematic, but when it grows larger, it can cause some discomfort. It can be removed by simple surgical excision. They are developed late in life, generally up to the sixth decade of age.

Epidemiology

- Incidence: uncommon

- Age: children and young adults

Site

- Scrotal skin

Presentation

- Single or multiple hard, marble-like nodules of varying size affecting scrotal skin.

- Nodules vary in size from a few millimeters to a few centimeters.

- Usually start to appear in childhood or early adult life

- Over time, nodules increase in number and size

- Nodules may break down and discharge chalky material

- Rarely, lesions may be polypoid

- Usually asymptomatic

Treatment

- Symptomatic single or grouped nodules can be excised surgically

Prognosis

- Benign condition

- Slow progression throughout life

- Lesions remain discrete and do not become confluent

The cause is not well defined. Originally considered idiopathic condition. Now accepted that majority of cases develop from dystrophic calcification of cyst contents.

The histological and ultrastructural features of Ledderhose and Dupuytren's disease are the same, which supports the hypothesis that they have a common cause and pathogenesis. As with Dupuytren's disease, the root cause(s) of Ledderhose's disease are not yet understood. It has been noted that it is an inherited disease and of variable occurrence within families, i.e. the genes necessary for it may remain dormant for a generation or more and then surface in an individual, or be present in multiple individuals in the same generation with varying degree.

There are certain identified risk factors. The disease is more commonly associated with -

- A family history of the disease

- Higher incidence in males

- Palmar fibromatosis 10-65% of the time.

- Peyronie's disease

- Epilepsy patients

- Patients of diabetes mellitus

There is also a suspected, although unproven, link between incidence and alcoholism, smoking, liver diseases, thyroid problems, and stressful work involving the feet.

Amnion nodosum are nodules on the fetal surface of the amnion, and is frequently present in oligohydramnios. The nodules are composed of squamous cell aggregates derived from the vernix caseosa on the fetal skin.

Amnion nodosum and oligohydromnios are associated with pulmonary hypoplasia and renal agenesis. Amnion nodosum is granules on amnion whereas whitish nodules on the cord suggest a candidial infection.

Acne conglobata is a highly inflammatory disease presenting with comedones, nodules, abscesses, and draining sinus tracts.

This condition generally begins between the ages of 18 and 30. It usually persists for a very long time, and often until the patient is around 40 years old. Although it often occurs where there is already an active acne problem, it can also happen to people whose acne has subsided. Although the cause of this type of acne is unknown, it is associated with testosterone and thus appears mainly in men. It can be caused by anabolic steroid abuse and sometimes appears in men after stopping testosterone therapy. It can also happen to someone who has a tumor that is releasing large amounts of androgens, or to people in remission from diseases, such as leukemia. In certain persons, the condition may be triggered by exposure to aromatic hydrocarbons or ingestion of halogens.

In medicine, nodules are solid, elevated areas of tissue or fluid inside or under the skin with a diameter greater than 0.5 centimeters. Nodules may form on tendons and muscles in response to injury. The vocal cords may also develop nodules. Nodules are normally benign and often painless, although they can affect the functioning of the organ.

Vocal fold nodules, thyroid nodules and rheumatoid nodules are examples. Furuncles and Kaposi's sarcomata are known to cause dermatological nodules.

The sexual transmitted disease (STD) gonorrhea is also known for its cause of nodules on the genitalia and mouth for those who are victim to the disease.

Smaller (less than 0.5 cm) elevated soft tissue lesions may be termed papules.

Sclerotic fibromas are a cutaneous condition characterized by well-circumscribed, dome-shaped, dermal hypocellular nodules composed predominantly of sclerotic thick collagen bundles.

Acne conglobata presents with blackheads appearing around the face, neck, chest, upper arms and buttocks in groups of two or three. Pimples form around the blackheads; they are large and engorged with fluid and may be sensitive to touch. They remain for a while and continue to grow and fill with pus until they eventually rupture. After the lesion has drained, it fills up again. After they rupture, several nodules can fuse together to form larger shapes. The lesions remain for a long time. They form a scab in the center but they continue to spread outwards. When the lesions do eventually heal, they leave scars that can be the usual type of acne scar (atrophic) or a raised bump like those normally left behind by a burn or a cut (keloidal).

No preventive measure is known aside from avoiding the traumatic inoculation of fungi. At least one study found a correlation between walking barefoot in endemic areas and occurrence of chromoblastomycosis on the foot.

Tuberculous gumma (also known as a "metastatic tuberculous abscess" and "metastatic tuberculous ulcer") is a cutaneous condition characterized histologically by massive necrosis. Restated, this is a skin condition that results from hematogenous dissemination of mycobacteria from a primary focus, resulting in firm, nontender erythematous nodules that soften, ulcerate, and form sinuses.

A solitary trichoepithelioma is a cutaneous condition characterized by a firm dermal papules or nodules most commonly occurring on the face.

Granuloma faciale (GF) is an uncommon benign chronic skin disease of unknown origin characterized by single or multiple cutaneous nodules, usually occurring over the face. Occasionally, extrafacial involvement is noted, most often on sun-exposed areas.

Giant-cell fibroblastoma is a rare type of soft-tissue tumor marked by painless nodules in the dermis (the inner layer of the two main layers of tissue that make up the skin) and subcutaneous (beneath the skin) tissue. These tumors may come back after surgery, but they do not spread to other parts of the body. They occur mostly in boys and are related to dermatofibrosarcoma protuberans.

Angiolymphoid hyperplasia with eosinophilia (also known as: "Epithelioid hemangioma," "Histiocytoid hemangioma," "Inflammatory angiomatous nodule," "Intravenous atypical vascular proliferation," "Papular angioplasia," "Inflammatory arteriovenous hemangioma," and "Pseudopyogenic granuloma") usually presents with pink to red-brown, dome-shaped, dermal papules or nodules of the head or neck, especially about the ears and on the scalp.

It, or a similar lesion, has been suggested as a feature of IgG4-related skin disease, which is the name used for skin manifestations of IgG4-related disease.

Chromoblastomycosis occurs around the world, but is most common in rural areas between approximately 30°N and 30°S latitude. Madagascar and Japan have the highest incidence. Over two-thirds of patients are male, and usually between the ages of 30 and 50. A correlation with HLA-A29 suggests genetic factors may play a role, as well.

Colloid nodules, also known as adenomatous nodules or colloid nodular goiter are benign, noncancerous enlargement of thyroid tissue. Although they may grow large, and there may be more than one, they are not malignant and they will not spread beyond the thyroid gland. Colloid nodules are the most common kind of thyroid nodule.

Cavernous venous malformations present as rounded, bright red or deep purple, spongy nodules, occurring chiefly on the head and neck and may involve both the skin and the mucous membranes.

It can be associated with "KRIT1", "CCM2" or "PDCD10".

Infantile hemangiopericytoma (also known as "Congenital hemangiopericytoma") is a cutaneous condition characterized by single or multiple dermal and subcutaneous nodules that may be alarmingly large at birth or grow rapidly.

Infantile systemic hyalinosis or juvenile systemic hyalinosis is an allelic autosomal-recessive condition characterized by multiple skin nodules, hyaline deposition, gingival hypertrophy, osteolytic bone lesions, and joint contractures.

Plantar fascial fibromatosis, also known as Ledderhose's disease, Morbus Ledderhose, and plantar fibromatosis, is a relatively uncommon non-malignant thickening of the feet's deep connective tissue, or fascia. In the beginning, where nodules start growing in the fascia of the foot the disease is minor . Over time walking becomes painful. The disease is named after Dr. Georg Ledderhose, a German surgeon who described the condition for the first time in 1894. A similar disease is Dupuytren's disease, which affects the hand and causes bent hand or fingers.

As in most forms of fibromatosis, it is usually benign and its onset varies with each patient. The nodules are typically slow growing and most often found in the central and medial portions of the plantar fascia. Occasionally, the nodules may lie dormant for months to years only to begin rapid and unexpected growth. Options for intervention include radiation therapy, cryosurgery, treatment with collagenase clostridium histolyticum, or surgical removal only if discomfort hinders walking.

Progressive nodular histiocytosis is a cutaneous condition clinically characterized by the development of two types of skin lesions: superficial papules and deeper larger subcutaneous nodules.

The differential of TO includes amyloidosis, which is typically circumferential, papillomatosis, though this usually occurs in younger patients and can cause lung cavitation when disseminated, granulomatosis with polyangiitis, though this is circumferential as well and often involves distal lung cavitation as well. Relapsing polychondritis can also spare the posterior wall, though it is not typically nodular in appearance.

EN is associated with a wide variety of conditions, including:

- Idiopathic

In about 30–50% of cases, the cause of EN is unknown.

- Infection

- Streptococcal infection which, in children, is by far the most common precipitant,

- Primary infection of Tuberculosis

- "Mycoplasma pneumoniae"

- "Histoplasma capsulatum"

- "Yersinia"

- Epstein-Barr virus

- "Coccidioides immitis" (Valley fever)

- Cat scratch disease

- Autoimmune disorders, including

- Inflammatory bowel disease (IBD)

- Behçet's disease

- Sarcoidosis

- Pregnancy

- Medications, including

- Sulfonamides

- Penicillins

- Oral contraceptives

- Bromides

- Hepatitis B vaccination

- Cancer, including

- Non-Hodgkins lymphoma (NHL)

- Carcinoid tumours

- Pancreatic cancer

EN may also be due to excessive antibody production in lepromatous leprosy leading to deposition of immune complexes.

There is an association with the HLA-B27 histocompatibility antigen, which is present in 65% of patients with erythema nodosum.

A useful mnemonic for causes is SORE SHINS (Streptococci, OCP, Rickettsia, Eponymous (Behçet), Sulfonamides, Hansen's Disease (Leprosy), IBD, NHL, Sarcoidosis.