Reticular erythematous mucinosis (REM) — also known as Midline mucinosis, Plaque-like cutaneous mucinosis, and REM syndrome — is a skin condition caused by fibroblasts producing abnormally large amounts of mucopolysaccharides. It is a disease that tends to affect women in the third and fourth decades of life.

Cherry angiomas are made up of clusters of capillaries at the surface of the skin, forming a small round dome ("papule") , which may be flat topped . They range in colour from bright red to purple. When they first develop, they may be only a tenth of a millimeter in diameter and almost flat, appearing as small red dots. However, they then usually grow to about one or two millimeters across, and sometimes to a centimeter or more in diameter . As they grow larger, they tend to expand in thickness, and may take on the raised and rounded shape of a dome. Multiple adjoining angiomas are said to form a "polypoid angioma". Because the blood vessels comprising an angioma are so close to the skin's surface, cherry angiomas may bleed profusely if they are injured.

One study found that the majority of capillaries in cherry hemangiomas are fenestrated because of staining for carbonic anhydrase activity.

Malakoplakia or malacoplakia (from Greek "Malako" "soft" + "Plako" "plaque") is a rare inflammatory condition which makes its presence known as a papule, plaque or ulceration that usually affects the genitourinary tract. However, it may also be associated with other bodily organs. It was initially described in the early 20th century as soft yellowish plaques found on the mucosa of the urinary bladder. Microscopically it is characterized by the presence of foamy histiocytes with basophilic inclusions called Michaelis–Gutmann bodies.

It usually involves gram-negative bacteria.

Syringofibroadenoma (also known as "acrosyringeal nevus of Weedon and Lewis") is a cutaneous condition characterized by a hyperkeratotic nodule or plaque involving the extremities.

It is considered of eccrine origin.

Retiform parapsoriasis is a cutaneous condition, considered to be a type of large-plaque parapsoriasis. It is characterized by widespread, ill-defined plaques on the skin, that have a net-like or zebra-striped pattern. Skin , a wasting away of the cutaneous tissue, usually occurs within the area of these plaques.

Cherry angiomas, also known as Campbell De Morgan spots or senile angiomas, are cherry red papules on the skin. They are a harmless (benign) tumor, containing an abnormal proliferation of blood vessels, and have no relationship to cancer. They are the most common kind of angioma, and increase with age, occurring in nearly all adults over 30 years.

Campbell de Morgan is the nineteenth-century British surgeon who first described them.

PVA can be characterized by speckled, combined hyper- and hypopigmentation in the plaques or patches of affected skin. Hyperpigmentation is excess coloration, or darkening of the skin, while hypopigmentation is a diminished or pallid coloring to the skin. Pigmentation changes in PVA, apparent in the epidermal (outermost) skin layer, may be attributed to incontinence (leaking out) of melanin from melanocytes into the dermal skin layer below. Inflammation of the skin and cutaneous tissue, common with PVA, also contributes to color changes in the skin, typified by redness. Telangiectasia, the visible "vascular" element of PVA, is the of small blood vessels near the skin surface. Skin atrophy, a wasting-away of the tissue comprising the skin, is a prominent part of PVA and effects the dermal, and particularly the epidermal layer. This, in part, is the result of degenerative of the stratum basale (bottom cell-layer) of the epidermis. Atrophy of the skin gives it a thin, dry and wrinkled appearance, which in PVA-affected individuals has been described as "cigarette paper". Hyperkeratosis, a thickening of the stratum corneum (top cell-layer of the epidermis), has also been reported.

The terms gingival hyperplasia and gingival hypertrophy have been used to describe this topic in the past. These are not precise descriptions of gingival enlargement because these terms are strictly histologic diagnoses, and such diagnoses require microscopic analysis of a tissue sample. Hyperplasia refers to an increased number of cells, and hypertrophy refers to an increase in the size of individual cells. As these identifications obviously cannot be performed with a clinical examination and evaluation of the tissue, the term "gingival enlargement" is more properly applied. Gingival enlargement has been classified according to cause into 5 general groups:

- Inflammatory enlargement

- Drug induced enlargement

- Enlargement associated with systemic diseases or conditions

- Neoplastic enlargement

- False enlargement.

Gingival enlargement, (also termed gingival overgrowth, hypertrophic gingivitis, gingival hyperplasia, or gingival hypertrophy, and sometimes abbreviated to GO), is an increase in the size of the gingiva (gums). It is a common feature of gingival disease. Gingival enlargement can be caused by a number of factors, including inflammatory conditions and the side effects of certain medications. The treatment is based on the cause. A closely related term is epulis, denoting a localized tumor (i.e. lump) on the gingiva.

Clear cell acanthoma (also known as "Acanthome cellules claires of Degos and Civatte," "Degos acanthoma," and "Pale cell acanthoma") is a benign clinical and histological lesion initially described as neoplastic, which some authors now regard as a reactive dermatosis. It usually presents as a moist solitary firm, brown-red, well-circumscribed, 5 mm to 2 cm nodule or plaque on the lower extremities of middle-aged to elderly individuals The lesion has a crusted, scaly peripheral collarette and vascular puncta on the surface. It is characterized by slow growth, and may persist for years. The clinical differential diagnosis includes: dermatofibroma, inflamed seborrheic keratosis, pyogenic granuloma, basal cell carcinoma, squamous cell carcinoma, verruca vulgaris, psoriatic plaque, and melanoma.

Vulvar Paget disease presents as a variety of clinical lesions that may occur over a protracted course. Initially it is velvety, soft, and red or bright pink with scattered white islands of hyperkeratosis. (a strawberry and cream appearance) The lesions become erythematous, plaque like, and desquamating especially when located in dry areas. Rarely the appearance is ulcerated. The borders appear irregular, slightly elevated, and sharply demarcated. The visible borders of vulvar Paget disease are often misleading as Paget cells may spread along the basal layers of normal appearing skin with multicentric foci. Involvement may be extensive including the perianal region, genitocrural, and inguinal folds. Clinical examination should determine the presence of periurethral and perianal lesions. In these cases an involvement of the skin by a noncutaneous internal neoplasm may occur.

Symptoms are not specific; most patients report itching, burning, and soreness. A small subset of patients may be asymptomatic. Presence of vulvar pain, bleeding, and tumor formation are reported to be more common in patients affected by invasive disease.Signs and symptoms are skin lesions, often mistaken as eczema, that may be itchy or painful.

Clear cell acanthoma is characterized by a sharply demarcated psoriasiform epidermal hyperplasia composed of a proliferation of slightly enlarged keratinocytes, and basal cells with pale-staining glycogen-rich cytoplasm, mild spongiosis and scattered neutrophils, which may form small intraepidermal microabscesses. Oedematous dermal papillae are typically seen with increased vascularity and a mixed inflammatory infiltrate including lymphocytes, plasma cells and neutrophils.

Solar purpura (also known as "Actinic purpura," and "Senile purpura") is a skin condition characterized by large, sharply outlined, 1- to 5-cm, dark purplish-red ecchymoses appearing on the dorsa of the forearms and less often the hands.

The condition is most common in elderly people of European descent. It is caused by sun-induced damage to the connective tissue of the skin.

No treatment is necessary. The lesions typically fade over a period of up to 3 weeks.

PVA usually has an underlying cause, attributed to existing skin diseases and disorders associated with a cutaneous lymphoma or inflammation. Mycosis fungoides is the common lymphoma believed to cause PVA, although it may be considered a precursor when the lymphoma is (hidden) and undiagnosed. Large plaque parapsoriasis is another common causes of PVA. Less common causes include autoimmune-related connective tissue diseases such as lupus, dermatomyositis and scleroderma. Dermatoses and those that are genetically inspired, called genodermatoses, may also be an underlying cause of PVA. Among them, xeroderma pigmentosum and Rothmund-Thomson syndrome (poikiloderma congenita) are thought to be the most prominent. Ingestion of substances containing arsenic, such as arsphenamine, has also been suggested as a least common cause. PVA can also be idiopathic (of unknown cause), as seen in a small number of cases.

Large plaque parapsoriasis (also known as "parapsoriasis en plaques") are skin lesions that may be included in the modern scheme of cutaneous conditions described as parapsoriasis. These lesions, called plaques, may be irregularly round-shaped to oval and are or larger in diameter. They can be very thin plaques that are asymptomatic or mildly pruritic. Large-plaque parapsoriasis is a common associate of retiform parapsoriasis, can be accompanied by poikiloderma vasculare atrophicans, and can in rare occasions be a precursor to cutaneous T-cell lymphoma.

Malakoplakia is thought to result from the insufficient killing of bacteria by macrophages. Therefore, the partially digested bacteria accumulate in macrophages and leads to a deposition of iron and calcium. The impairment of bactericidal activity manifests itself as the formation of an ulcer, plaque or papule.

Malakoplakia is associated with patients with a history of immunosuppression due to lymphoma, diabetes mellitus, renal transplantation, or because of long-term therapy with systemic corticosteroids.

Michaelis gutmann bodies present

Congenital smooth muscle hamartoma is typically a skin colored or lightly pigmented patch or plaque with hypertrichosis.

It is one of the seven destructive periodontal diseases as listed in the 1999 classification.

Eccrine carcinoma (also known as a syringoid carcinoma) is a rare cutaneous condition characterized by a plaque or nodule on the scalp, trunk, or extremities.

It is usually seen when a physician performs ophthalmoscopy, during which a plaque will appear bright, refractile, and yellow. It is caused by an embolus lodged within the retinal vessel that originated from an atheromatous plaque in a more proximal (upstream) vessel, usually the internal carotid artery. It is often an indication of a previous ischemic episode in the eye and is a sign of severe atherosclerosis. The most important step in management is to identify and treat the originating plaque to prevent further embolization.

Parapsoriasis refers to one of a group of skin disorders that are characterized primarily by their resemblance to psoriasis (red, scaly lesions), rather than by their underlying cause.

Neoplasms can develop from parapsoriasis. For example, it can develop into cutaneous T-cell lymphoma.

The word "parapsoriasis" was formed in 1902.

Lick granuloma is a form of self-trauma and skin disorder in which most commonly dogs, but also cats, continuously lick a small area of their body until it becomes raw and inflamed. The most common areas affected are the lower (distal) portions of their legs, such as the carpus (wrist), or sometimes another part of their body such as the base of their tail.

The lesion can initially be red, shiny, swollen, hairless, irritated, and bleeding, similar to a hot spot (wet eczema). Eventually a raised hard plaque forms.

A Hollenhorst plaque a.k.a. "Eickenhorst plaque" is a cholesterol embolus that is seen in a blood vessel of the retina.

The parapsoriasis groups, described and debated for nearly a century, has spawned a confusing nomenclature. There are some authors who prefer to limit the term "parapsoriasis" to large- and small-plaque variants only. However, the following classification scheme is now generally accepted:

- Large-plaque parapsoriasis

- Small-plaque parapsoriasis

- Pityriasis lichenoides

- Pityriasis lichenoides chronica

- Pityriasis lichenoides et varioliformis acuta

- Lymphomatoid papulosis