Pigmented lesionsof the oral mucosa
د. رائدة الكبيسي
Pigmented lesions of the oral mucosa
The endogenous pigmentation -- hemoglobin, hemosiderin, and melanin Exogenous pigments are usually traumatically deposited directly into the submucosa.
Endogenous pigmentation:
Focal melanocytic pigmentation
Ephelis and Oral Melanotic Macule:macular increase in melanin pigment synthesis
on the vermilion border of the lips, with the lower lip being the favored site Lip ephelides are asymptomatic and occur equally in men and women-The intraoral melanotic macule. These lesions are oval or irregular in outline, brown or even black, and tend to occur on the gingiva, palate, and buccal mucosa. Once they reach a certain size, they do not tend to enlarge further. The oral melanotic macule is innocuous, Once it is removed, no further surgery is required.
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Nevocellular Nevus and Blue Nevus:
Nevocellular nevi arise from basal-layer melanocytes early in life. benign proliferations of melanocytes
In the evolutionary stages, nevi are macular and are classified as junctional nevi. In general, they are flat and brown and have a regular round or oval outline.
With time, the melanocytes form clusters at the epitheliomesenchymal junction and begin to proliferate down into the connective tissue although they do not invade vessels or lymphatics. Such nevi assume a dome shaped appearance and are referred to as compound nevi. In late puberty, the melanocytes in compound nevi lose their continuity with the surface epithelium, and the cells become localized to the deeper connective tissues. They are then termed intradermal nevi when on skin and intramucosal nevi when in the mouth. On the skin-elevated brown nodules that often have hair
The second type of nevus, not derived from basal-layer melanocytes, is the blue nevus. The blue nevus is blue on the skin because the melanocytic cells reside deep in the connective tissue and because the overlying vessels dampen the brown coloration of melanin, yielding a blue tint.
In the oral mucosa, both nevocellular and blue nevi tend to be brown and may be macular or nodular. They may be seen at any age and are found most frequently on the palate and gingiva but may also be encountered in the buccal mucosa and on the lips. Once they reach a given size, their growth ceases, and the lesions remain static.
Malignant Melanoma:
On the facial skin, the malar region is a common site for melanoma because this area of the face is subject to significant solar exposure. Facial cutaneous melanomas may appear macular or nodular, and the coloration can be quite varied, ranging from brown to black to blue, with zones of depigmentation.
melanomas show jagged irregular margins.
elderly patients and show a male predilection.
These lesions have a good prognosis if they are detected and treated before the appearance of nodular lesions
Mucosal melanomas are extremely rare. Melanomas arising in the oral mucosa tend to occur on the anterior labial gingiva and the anterior aspect of the hard palate. In the early stages, oral melanomas are macular brown and black plaques with an irregular outline. Eventually, melanomas become more diffuse, nodular, and tumefactive, with foci of hyper- and hypopigmentation.
Once vertical growth into the connective tissue progresses, the lesions can become clinically tumefactive. The vertical growth phase ---- a poor prognosis because of the likelihood of lymphatic and hematogenous metastasis.
Excision with wide margins is the treatment of choice; once nodularity has evolved, however, the lesion has probably already metastasized. Computed tomography and magnetic resonance imaging studies should be undertaken to explore regional metastases to the submandibular and cervical lymph nodes. A variety of chemo- and immunotherapeutic strategies can be used once metastases have been identified.
Multifocal\diffuse melanocytic pigmentation
Physiologic Pigmentation:
Dark-skinned people --diffuse melanosis of the facial gingiva, the lingual gingiva and tongue may exhibit multiple, diffuse, and reticulated brown macules. Racial pigmentation represents basilar melanosis, evolves in childhood and usually does not arise de novo in the adult. Therefore, any multifocal or diffuse pigmentation of recent onset should be investigated further to rule out endocrinopathic disease.
Drug-Induced Melanosis:
The chief drugs implicated are the quinoline and hydroxyquinoline antimalarials. These medications have also been used in the treatment of autoimmune diseases. Minocycline, used in the treatment of acne, The pigment is not confined to oral mucosa and is also encountered in the nail bed and on the skin. Last, oral contraceptives and pregnancy. This condition is referred to as melasma or chloasma. The cause is unknown, and the pigment may remain for quite some time after withdrawal of the incriminated drug. Microscopically, basilar melanosis without melanocytic proliferation is observed.
Smoker’s Melanosis:
Diffuse macular melanosis of the buccal mucosa, lateral tongue, palate, and floor of the mouth. The lesions are brown, flat, and irregular; some are even geographic or map-like in configuration. Histologically, basilar melanosis with melanin incontinence is observed, and the lesions have no premalignant potential.
Pigmented Lichen Planus:
Reticulated white patches, with or without a red erosive component are flanked by diffuse brown macular foci. This increase in melanogenesis may be stimulated by the infiltrate of T lymphocytes into the basal layer that contribute to basal cell degeneration.
Melanosis associated with systemic or genetic disease
Endocrinopathic Pigmentation:
Bronzing of the skin and patchy melanosis of the oral mucosa are signs of Addison’s disease and pituitary-based Cushing’s syndrome -with melanocyte-stimulating properties. In Addison’s disease, adrenocortical insufficiency evolves as a consequence of granulomatous infection of the cortex or autoimmune cortical destruction. As steroid hormones decrease, the feedback loop is stimulated with excess secretion of ACTH by pituitary gland. The patient develops hypotension and hypoglycemia, respectively.
In Cushing’s syndrome, if the hypercorticism is the consequence of a pituitary ACTH-secreting tumor that secondarily induces an adrenal hypersecretion, then melanocyte-stimulating effects may evolve. Patients with Cushing’s syndrome may be hypertensive and hyperglycemic and may show facial edema “moon face”.
In both cases, the changes in pigmentation are due to an accumulation of melanin granules. the pigment will disappear once appropriate therapy for the endocrine problem is initiated.
Addison’s disease
HIV Oral Melanosis:
diffuse macular pigmentations. The buccal mucosa is the most frequently affected site, but the gingiva, palate, and tongue may also be involved., HIV-associated pigmentation is microscopically characterized by basilar melanin pigment, with incontinence into the underlying submucosa.
Peutz-Jeghers Syndrome:
This autosomal dominant syndrome comprises intestinal polyposis and melanotic macules, particularly of the face and mouth.
There are multiple freckles on the lips and oral mucosa. (mainly around the mouth, eyes and nose) usually fades after puberty, but mucosal pigmentation persists.
Polyps may be present throughout the gastrointestinal tract. Colon cancer is a possible hazard but the risk for breast and gynecological cancers is particularly high.
Histologically, these lesions show basilar melanogenesis without melanocytic proliferation.
• Depigmentation
Vitiligo:
It is relatively common acquired autoimmune disease, with incidence of 0.5-2% in the general population. The pathogenesis of vitiligo is multifactorial,The lesions present as well circumscribed round, oval or elongated pale or white colored macules that may coalesce into larger area of diffuse depigmentation. signs of the disease before the third decade of life. Vitiligo -immunotherapy. Vitiligo rarely affects intraoral mucosal tissues.
Topical corticosteroid and photochemotherapies.
Vascular lesions
Hemangioma and Vascular malformations:
Hemangiomas are considered to be benign tumors of infancy that are characterized by a rapid growth phase with endothelial cell proliferation, followed by gradual involution.
A pale macule with threadlike telangiectasias may be noted on the skin.
During the first few weeks of life, the tumor will demonstrate rapid development. ٭Superficial tumors of the skin appear raised with a bright-red color ("strawberry" hemangioma). They are firm and rubbery to palpation, and the blood cannot be evacuated by applying pressure. ٭Deeper tumors may appear only slightly raised with a bluish hue. The proliferative phase usually lasts for 6 to 10 months.
After which the tumor slows in growth and begins to involute.
About half of all hemangiomas will show complete resolution by 5 years of age, with 90% resolving by age 9.
Vascular malformations are structural anomalies of blood vessels without endothelial proliferation. In contrast to hemangiomas, vascular malformations are present at birth and persist throughout life. Port wine stains are relatively common capillary malformations that occur in 0.3% to 1% of newborns. They are most common on the face, particularly along the distribution of the trigeminal nerve. In Sturge-Weber angiomatosis, associated intracranial lesions are present there is a concurrent history of seizures. Port wine stains are typically pink or purple macular lesions that grow commensurately with the patient. As the patient gets older, the lesion often darkens and becomes nodular because of vascular ectasia.
. Sturge-Weber angiomatosis. Port wine stain of the left face, including involvement along the ophthalmic branch of t he trigeminal nerve. The patient also was mentally retarded and had a seizure disorder
Rt…..conventional surgery, laser surgery, or cryosurgery. Larger lesions that extend into muscles are more difficult to eradicate surgically, and sclerosing agents. Cutaneous port-wine stains can be treated by subcutaneous tattooing or by argon laser.
• Varix:
Pathologic dilatations of veins or venules are varices --the ventral tongue. Varicosities become progressively prominent with age;. Lingual varicosities appear as tortuous blue, red, and purple elevations that course over the ventrolateral surface of the tongue. They are painless and are not subject to rupture and hemorrhage.
The varix resembles the hemangioma, yet it is distinguished by two features: (1) the patient’s age at its onset and (2) its etiology. A hemangioma is usually congenital and has a tendency to spontaneously regress whereas a varix arises in older individuals and, once formed, does not regress. Whereas hemangiomas are vascular hamartomas of unknown etiology, the varix represents a venous dilatation that may evolve from trauma such as lip or cheek biting.
The lesion can be excised or removed by other surgical methods, including electrosurgery and cryosurgery. Intralesional sclerosing agent injection is effective as well.
Angiosarcoma:
Malignant vascular neoplasms, distinct from Kaposi’s sarcoma, are not related to human. Although the oral cavity is an extremely rare site for such tumors, (if superficial) appear red, blue, or purple. They are rapidly proliferative and therefore present as nodular tumors. Angiosarcomas can arise from blood or lymph vessel endothelial cells. They have a poor prognosis and are treated by radical excision.
• Kaposi’s Sarcoma (KS):
The most common neoplastic process to accompany HIV infection.
The cutaneous lesions begin as red macules and enlarge to become blue, purple, and ultimately brown nodular tumefactions. The lesions may appear on the arms, face, scalp, or trunk.The oral lesions continue to show a predilection for the posterior hard palate and facial gingiva. They begin as flat red macules of variable size and irregular configuration---increase in size to become nodular growths.
Surgical excision is not usually attended by severe hemorrhage. Intralesional injection of sclerosing agent will result in necrosis of the tumefactions.
Hereditary hemorrhagic telangiectasia (HHT):
Characterized by multiple round or oval purple papules measuring less than 0.5 cm in diameter, HHT is a genetically transmitted disease, inherited as an autosomal dominant trait. The lesions represent multiple microaneurysms, owing to a weakening defect in the adventitial coat of venules. There may be more than 100 such purple papules on the vermilion and mucosal surfaces of the lips as well as on the tongue and buccal mucosa.
Multiple small purple papules of hereditary hemorrhagic telangiectasia.
• Haemoglobin and iron associated pigmentationPurpura; reddish to purple flat lesions caused by blood from vessels leaking into the subcutaneous tissue.
Ecchymosis:
Traumatic ecchymosis is common on the lips and face yet is uncommon in the oral mucosa.→ erythrocyte extravasation into the submucosa will appear as a bright red macule or as a swelling if a hematoma forms→→a brown coloration within a few days, after the hemoglobin is degraded to hemosiderin.
Coagulopathic ecchymosis of the skin and oral mucosa, particularly on the cheek or tongue which can be traumatized while chewing, may be encountered in patients taking anticoagulant drugs, hereditary coagulopathic disorders and in chronic liver failure.
Petechia:
associated with thrombocytopenia or thrombocytopathia. →to the soft palate and can be attributed to suction. Excessive suction of the soft palate against the posterior tongue is self inflicted by many patients who have a pruritic palate at the onset of a viral or an allergic pharyngitis; they simply “click” their palate.
• Hemochromatosis:
chronic progressive disease →excessive iron deposition in the liver and other organs and tissues →diffuse brown to gray in appearance→The palate and gingiva -commonly affected.Exogenous pigmentation:
Amalgam Tattoo:
The lesions are macular and bluish gray or even black and are usually seen in the buccal mucosa, gingiva, or palate..
Graphite Tattoo:
→palate and represent traumatic implantation from a lead pencil →macular, focal, and gray or black.
• Hairy Tongue::
unknown etiology. The lesion involves the dorsum, particularly the middle and posterior one-third. Rarely are children affected. The papillae are elongated, and have the appearance of hairs. The hyperplastic papillae then become pigmented by the colonization of chromogenic bacteria, which can impart a variety of colors ranging from green to brown to black. Various foods, particularly coffee and tea, probably contribute to the diffuse coloration.Treatment consists of having the patient brush the tongue and avoid tea and coffee for a few weeks. Since the cause is undetermined, the condition can recur.
• Pigmentation Related to Heavy-Metal Ingestion
Lead, mercury, and bismuth have all been shown to be deposited in oral tissue, if ingested in sufficient quantities or over a long course of time.These ingested pigments tend to extravasate from vessels in foci of increased capillary permeability such as inflamed tissues. Thus, in the oral cavity, the pigmentation is usually found along the free marginal gingiva. This metallic line has a gray to black appearance.
The heavy metals may be associated with systemic symptoms of toxicity, including behavioral changes, neurologic disorders, and intestinal pain.
