Swelling is the most common presenting complaint; however, OKCs may be asymptomatic and found incidentally on dental X-rays.

Malignant transformation to squamous cell carcinoma may occur, but is unusual.

Heck's disease (also known as focal or multifocal epithelial hyperplasia) is an asymptomatic, benign neoplastic condition characterized by multiple white to pinkish papules that occur diffusely in the oral cavity. Can present with slightly pale, smooth or roughened surface morphology. It is caused by the human papilloma virus types 13 and 32. It exhibits surface cells with vacuolated cytoplasm around irregular, pyknotic nuclei and occasional cells with mitosis-like changes within otherwise mature and well-differentiated epithelium. A distinguishing histologic feature is elongated rete ridges resembling Bronze Age axe with mitosoid bodies present. It was first identified in the Aboriginal population.

Over time, they will spontaneously regress without treatment. Possible treatment may be excisional biopsy for lesions of functional or aesthetic concern.

A struma ovarii (literally: goitre of the ovary) is a rare form of monodermal teratoma that contains mostly thyroid tissue, which may cause hyperthyroidism.

Despite its name, struma ovarii is not restricted to the ovary.

The vast majority of struma ovarii are benign tumors; however, malignant tumors of this type is found in a small percentage of cases.

Teratomas maybe found in babies, children, and adults. Teratomas of embryonal origin are most often found in babies at birth, in young children, and, since the advent of ultrasound imaging, in fetuses.

The most commonly diagnosed fetal teratomas are sacrococcygeal teratoma (Altman types I, II, and III) and cervical (neck) teratoma. Because these teratomas project from the fetal body into the surrounding amniotic fluid, they can be seen during routine prenatal ultrasound exams. Teratomas within the fetal body are less easily seen with ultrasound; for these, MRI of the pregnant uterus is more informative.

GCNIS is seen in the following settings:

- Almost all invasive germ cell tumours of the testis in adults

- Fifty percent of patients with GCNIS developed invasive germ cell tumours within five years of initial diagnosis.

- Five percent of contralateral testes in men with a history of prior testicular germ cell tumour.

- Less than five percent of cryptorchid testes.

- Less than one percent of patients with infertility.

A teratoma is a tumor made up of several different types of tissue, such as hair, muscle, or bone. They typically form in the ovaries, testicles, or tailbone and less commonly in other areas. Symptoms may be minimal if the tumor is small. A testicular teratoma may present as a painless lump. Complications may include ovarian torsion, testicular torsion, or hydrops fetalis.

They are a type of germ cell tumor (a tumor that begins in the cells that give rise to sperm or eggs). They are divided into two types mature and immature. Mature teratomas include dermoid cysts and are generally benign. Immature teratomas may be cancerous. Most ovarian teratomas are mature. In adults, testicular teratomas are generally cancerous. Definitive diagnosis is based on a tissue biopsy.

Treatment of tailbone, testicular, and ovarian teratomas is generally by surgery. Testicular and immature ovarian teratomas are also frequently treated with chemotherapy.

Teratomas occur in the tailbone in about 1 in 30,000 newborns making them the most common tumor in this age group. Females are affected more often than males. Ovarian teratomas represent about a quarter of ovarian tumors and are typically noticed during middle age. Testicular teratomas represent almost half of testicular cancers. They can occur in both children and adults. The term comes from the Greek words for "monster" and "tumor".

Not all germ cell tumors (GCTs) arise from "intratubular germ cell neoplasia". The following testicular GCTs do not arise from ITGCN:

- Spermatocytic seminoma

- Pediatric Yolk sac tumors (endodermal sinus tumour). This is currently an area of controversy as some authors dispute the absence of ITGCN in these cases.

- Teratoma (rare exceptions)

Often, this disease evolves from a precursor lesion, usually a dysplastic nevus. Otherwise it arises in previously normal skin. A prolonged radial growth phase, where the lesion remains thin, may eventually be followed by a vertical growth phase where the lesion becomes thick and nodular. As the risk of spread varies with the thickness, early SSM is more frequently cured than late nodular melanoma.

The microscopic hallmarks are:

- Large melanocytic cells with nest formation along the dermo-epidermal junction.

- Invasion of the upper epidermis in a pagetoid fashion (discohesive single cell growth).

- The pattern of rete ridges is often effaced.

- Invasion of the dermis by atypical, pleomorphic melanocytes

- Absence of the 'maturation' typical of naevus cells

- Mitoses

Superficial spreading melanoma (also known as "superficially spreading melanoma") (SSM) is usually characterized as the most common form of cutaneous melanoma in Caucasians. The average age at diagnosis is in the fifth decade, and it tends to occur on sun-exposed skin, especially on the backs of males and lower limbs of females.

The ultrasound (US) features of struma ovarii are nonspecific, but a heterogeneous, predominantly solid mass may be seen. US demonstrates a complex appearance with multiple cystic and solid areas, findings that reflect the gross pathologic appearance of the tumor.

Magnetic resonance imaging findings may be more characteristic: The cystic spaces demonstrate both high and low signal intensity on T1- and T2-weighted images. Some of the cystic spaces may demonstrate low signal intensity on both T1- and T2-weighted images due to the thick, gelatinous colloid of the struma. No fat is evident in these lesions.

Epulis (literally, 'on the gingiva') is a general term for any gingival or alveolar tumor (i.e. lump on the gum). This term describes only the location of a lump and has no implication on the histologic appearance of a lesion. "Epulis" is also sometimes used synonymously with epulis fissuratum, however other conditions are classified as epulides, e.g. giant cell epulis (peripheral giant cell granuloma), ossifying fibroid epulis (peripheral ossifying fibroma), and congenital epulis.

The lesion is usually painless. The usual appearance is of two excess tissue folds in alveolar vestibule/buccal sulcus, with the flange of the denture fitting in between the two folds. It may occur in either the maxillary or mandibular sulci, although the latter is more usual. Anterior locations are more common than posterior. Less commonly there may be a single fold, and the lesion may appear on the lingual surface of the mandibular alveolar ridge.

The swelling is firm and fibrous, with a smooth, pink surface. The surface may also show ulceration or erythema. The size of the lesion varies from less than 1 cm to involving the entire length of the sulcus.

There is a diffuse, gray-white, milky opalescent appearance of the mucosa which usually occurs bilaterally on the buccal mucosa. Less often, the labial mucosa, the palate or the floor of mouth may be affected. The surface of the area is folded, creating a wrinkled, white streaked lesion. Apart from the appearance, the lesion is entirely asymptomatic.

In the context of lesions of the mucous membrane lining of the bladder, leukoplakia is a historic term used to describe a visualized white patch which histologically represents keratinization in an area of squamous metaplasia. The symptoms may include frequency, suprapubic pain (pain felt above the pubis), hematuria (blood in the urine), dysuria (difficult urination or pain during urination), urgency, and urge incontinence. The white lesion may be seen during cystoscopy, where it appears as a whitish-gray or yellow lesion, on a background of inflamed urothelium and there may be floating debris in the bladder. Leukoplakia of the bladder may undergo cancerous changes, so biopsy and long term follow up are usually indicated.

Most cases of leukoplakia cause no symptoms, but infrequently there may be discomfort or pain. The exact appearance of the lesion is variable. Leukoplakia may be white, whitish yellow or grey. The size can range from a small area to much larger lesions. The most common sites affected are the buccal mucosa, the labial mucosa and the alveolar mucosa, although any mucosal surface in the mouth may be involved. The clinical appearance, including the surface texture and color, may be homogenous or non-homogenous (see: classification). Some signs are generally associated with a higher risk of cancerous changes (see: prognosis).

Leukoplakia may rarely be associated with esophageal carcinoma.

Spermatocele () is a retention cyst of a tubule of the rete testis or the head of the epididymis distended with barely watery fluid that contains spermatozoa. Small spermatoceles are relatively common, occurring in an estimated 30 percent of all men. They vary in size from several millimeters to many centimeters. Spermatoceles are generally not painful. However, some men may experience discomfort from larger spermatoceles. They are not cancerous, nor do they cause an increased risk of testicular cancer. Additionally, unlike varicoceles, they do not have a negative impact on fertility.

Leukoedema (also spelled leucoedema) is a blue, grey or white appearance of mucosae, particularly the buccal mucosa (the inside of the cheeks); it may also occur on the mucosa of the larynx or vagina. It is a harmless and very common condition. Because it is so common, it has been argued that it may in fact represent a variation of the normal appearance rather than a disease, but empirical evidence suggests that leukoedema is an acquired condition caused by local irritation. It is found more commonly in black skinned people and tobacco users. The term is derived from the Greek words λευκός "leukós", "white" and οἴδημα "oídēma", "swelling".

Many conditions affect the human integumentary system—the organ system covering the entire surface of the body and composed of skin, hair, nails, and related muscle and glands. The major function of this system is as a barrier against the external environment. The skin weighs an average of four kilograms, covers an area of two square meters, and is made of three distinct layers: the epidermis, dermis, and subcutaneous tissue. The two main types of human skin are: glabrous skin, the hairless skin on the palms and soles (also referred to as the "palmoplantar" surfaces), and hair-bearing skin. Within the latter type, the hairs occur in structures called pilosebaceous units, each with hair follicle, sebaceous gland, and associated arrector pili muscle. In the embryo, the epidermis, hair, and glands form from the ectoderm, which is chemically influenced by the underlying mesoderm that forms the dermis and subcutaneous tissues.

The epidermis is the most superficial layer of skin, a squamous epithelium with several strata: the stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum basale. Nourishment is provided to these layers by diffusion from the dermis, since the epidermis is without direct blood supply. The epidermis contains four cell types: keratinocytes, melanocytes, Langerhans cells, and Merkel cells. Of these, keratinocytes are the major component, constituting roughly 95 percent of the epidermis. This stratified squamous epithelium is maintained by cell division within the stratum basale, in which differentiating cells slowly displace outwards through the stratum spinosum to the stratum corneum, where cells are continually shed from the surface. In normal skin, the rate of production equals the rate of loss; about two weeks are needed for a cell to migrate from the basal cell layer to the top of the granular cell layer, and an additional two weeks to cross the stratum corneum.

The dermis is the layer of skin between the epidermis and subcutaneous tissue, and comprises two sections, the papillary dermis and the reticular dermis. The superficial papillary dermis with the overlying rete ridges of the epidermis, between which the two layers interact through the basement membrane zone. Structural components of the dermis are collagen, elastic fibers, and ground substance. Within these components are the pilosebaceous units, arrector pili muscles, and the eccrine and apocrine glands. The dermis contains two vascular networks that run parallel to the skin surface—one superficial and one deep plexus—which are connected by vertical communicating vessels. The function of blood vessels within the dermis is fourfold: to supply nutrition, to regulate temperature, to modulate inflammation, and to participate in wound healing.

The subcutaneous tissue is a layer of fat between the dermis and underlying fascia. This tissue may be further divided into two components, the actual fatty layer, or panniculus adiposus, and a deeper vestigial layer of muscle, the panniculus carnosus. The main cellular component of this tissue is the adipocyte, or fat cell. The structure of this tissue is composed of septal (i.e. linear strands) and lobular compartments, which differ in microscopic appearance. Functionally, the subcutaneous fat insulates the body, absorbs trauma, and serves as a reserve energy source.

Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses, as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails). While only a small number of skin diseases account for most visits to the physician, thousands of skin conditions have been described. Classification of these conditions often presents many nosological challenges, since underlying etiologies and pathogenetics are often not known. Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane), morphology (chronic blistering conditions), etiology (skin conditions resulting from physical factors), and so on. Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion(s), including the location (such as arms, head, legs), symptoms (pruritus, pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology (macules, papules, vesicles), and color (red, blue, brown, black, white, yellow). Diagnosis of many conditions often also requires a skin biopsy which yields histologic information that can be correlated with the clinical presentation and any laboratory data.

Spermatoceles can be discovered as incidental scrotal masses found on physical examination by a physician. They may also be discovered by self-inspection of the scrotum and testicles.

Finding a painless, cystic mass at the head of the epididymis, that transilluminates and can be clearly differentiated from the testicle, is generally sufficient. If uncertainty exists, ultrasonography of the scrotum can confirm if it is spermatocele.

If an individual finds what he suspects to be a spermatocele, he is advised to consult a urologist.

Rarely is any soreness associated with the condition. Apart from the appearance of the lesion, there are usually no other signs or symptoms. The typical appearance of the lesion is an oval or rhomboid shaped area located in the midline of the dorsal surface of the tongue, just anterior (in front) of the sulcus terminalis. The lesion is usually symmetric, well demarcated, erythematous and depapillated, which has a smooth, shiny surface. Less typically, the lesion may be hyperplastic or lobulated and exophytic. There may be candidal lesions at other sites in the mouth, which may lead to a diagnosis of chronic multifocal oral candidiasis. Sometimes an approximating erythematous lesion is present on the palate as the tongue touches the palate frequently. The lesion is typically 2–3 cm in its longest dimension.

ILVEN is a condition that normally only affects one side of the body (unilateral). Usually the left side of patients is affected. The condition is persistent and forms along characteristic lines. It usually appears on an extremity in infancy or childhood. Altman and Mehregan described six characteristic features of ILVEN: (1) early age of onset, (2) predominance in females (4:1 female-male ratio), (3) frequent involvement of the left leg, (4) pruritus, or "itchiness" (5) marked refractoriness to therapy, and (6) a distinctive psoriasiform and inflammatory histologic appearance.

Median rhomboid glossitis (MRG, also known as central papillary atrophy, or glossal central papillary atrophy. ) is a condition characterized by an area of redness and loss of lingual papillae, situated on the dorsum of the tongue in the midline immediately in front of the circumvallate papillae. Median rhomboid glossitis is thought to be created by a chronic fungal infection, and usually is a type of oral candidiasis.

Although testicular cancer can be derived from any cell type found in the testicles, more than 95% of testicular cancers are germ cell tumors (GCTs). Most of the remaining 5% are sex cord-gonadal stromal tumours derived from Leydig cells or Sertoli cells. Correct diagnosis is necessary to ensure the most effective and appropriate treatment. To some extent, this can be done via blood tests for tumor markers, but definitive diagnosis requires examination of the histology of a specimen by a pathologist.

Most pathologists use the World Health Organization classification system for testicular tumors:

- Germ cell tumors

- "Precursor lesions"

- Intratubular germ cell neoplasia

- Unclassified type (carcinoma in situ)

- Specified types

- "Tumors of one histologic type (pure forms)"

- Seminoma

- Variant - Seminoma with syncytiotrophoblastic cells

- Spermatocytic seminoma

- Variant - spermatocytic seminoma with sarcoma

- Embryonal carcinoma

- Yolk sac tumor

- Trophoblastic tumors

- Choriocarcinoma

- Variant - monophasic choriocarcinoma

- Placental site trophoblastic tumour

- Cystic trophoblastic tumor

- Teratoma

- Variant - Dermoid cyst

- Variant - Epidermoid cyst

- Variant - Monodermal teratoma (Carcinoid, Primitive neuroectodermal tumor (PNET), Nephroblastoma-like tumor, others.

- Variant - Teratomic with somatic-type malignancy

- "Tumours of more than one histologic type (mixed forms)"

- Embryonal carcinoma and teratoma

- Teratoma and seminoma

- Choriocarcinoma and teratoma.embryonal carcinoma

- Others

- Sex cord/Gonadal stromal tumors

- Leydig cell tumor

- Sertoli cell tumor

- Lipid rich variant

- Scleriosing variant

- Large cell calcifying variant

- Intratubular sertoli cell neoplasia in Peutz-Jeghers syndrome

- Granulosa cell tumor

- Adult type

- Juvenile type

- Thecoma Fibroma Group

- Thecoma

- Fibroma

- Sex cord/gonadal stromal tumor - incompletely differentiated

- Sex cord/gonadal stromal tumor - mixed types

- Mixed Germ Cell and Sex Cord/Gonadal Stromal Tumors

- Gonadoblastoma

- Germ cell-sex cord/gonadal stromal tumor, unclassified

- Miscellaneous tumours of the testis

- Carcinoid

- Tumors of ovarian epithelial types

- Serous tumor of borderline malignancy

- Serous carcinoma

- Well differentiated endometrioid tumor

- Mucinous cystadenoma

- Mucinous cystadenocarcinoma

- Brenner tumor

- Nephroblastoma

- Paraganglioma

- Haematopoietic tumors

- Tumours of collecting ducts and rete

- Adenoma

- Carcinoma

- Tumors of the paratesticular structures

- Adenomatoid tumor

- Malignant and Benign Mesothelioma

- Adenocarcinoma of the epididymis

- Papillary cystadenoma of the epididymis

- Melanotic neuroectodermal tumor

- Desmoplastic small round cell tumor

- Mesenchymal tumors of the spermatic cord and testicular adnexae

- Lipoma

- Liposarcoma

- Rhabdomyosarcoma

- Aggressive angiomyxoma

- Angiomyofibroblastoma-like tumor (see Myxoma)

- Fibromatosis

- Fibroma

- Solitary fibrous tumor

- Others

- Secondary tumors of the testis

"Configuration" refers to how lesions are locally grouped ("organized"), which contrasts with how they are distributed (see next section).

- Agminate: in clusters

- Annular or circinate: ring-shaped

- Arciform or arcuate: arc-shaped

- Digitate: with finger-like projections

- Discoid or nummular: round or disc-shaped

- Figurate: with a particular shape

- Guttate: resembling drops

- Gyrate: coiled or spiral-shaped

- Herpetiform: resembling herpes

- Linear

- Mammillated: with rounded, breast-like projections

- Reticular or reticulated: resembling a net

- Serpiginous: with a wavy border

- Stellate: star-shaped

- Targetoid: resembling a bullseye

- Verrucous: wart-like