The benign tumors are a result of non harmful or non malignant uncontrolled multiplication of cells, which form a mass and are considered as tumours. Benign tumours do not have the ability to metastasize to other regions of the body or to invade any adjacent tissue and they grow in size at the location which they have started. In benign tumours the cells are usually well differentiated unlike Malignant tumours which are not well differentiated. When compared to Malignant tumours the Benign Tumours of Epithelial origin grow slower and have a precise shape.
Although the cells from Benign tumours do not invade adjacent tissues, due to increase in size of the tumours any adjacent Nerves may be impinged leading to damage to the nerves. So removal of the Benign tumours is required in some cases which have grown too large. Benign Tumours arising from Epithelial tissues are termed a Tumours of Epithelial origin and they are termed based on the tissue they arise from.
List of Benign tumours of Epithelial origin:
- Squamous Papilloma: An exophytic growth made up of numerous finger like projections which results in lesions that have an irregular surface which is a verrucous or cauliflower like surface. It is a well circumscribed pedunculated lesion. It is painless white but occasionally pink in color. It is found on the tongue, lips, buccal mucosa, gingiva and palate, adjacent to uvula.
- Squamous Acanthoma: A Small flat or elevated, sessile or pedunculated, white lesion of the oral cavity occurring any where. It has characteristic histologic appearances like the well demarcated, elevated or umbilicated epithelial proliferation, with a marked thickened layer of orthokeratin and underlying spinous layer of cells.
- Kerato Acanthoma: Also called as “Self healing carcinoma” It resembles clinically and pathologically squamous cell carcinoma. It is a low grade malignancy which originated in the pilo-sebaceous glands. It is a variant of invasive squamous cell carcinoma. Lesions are solitary, begin as firm, round, skin colored or reddish papules that rapidly progress to dome shaped nodules. with a smooth shiny surface and a central crateriform ulceration or keratin plug which projects like a horn from the surface.
- Oral Nevi: It is a flat and asymptomatic lesion of the oral cavity which is caused due to the melanin pigmentation of the stratified squamous epithelium. It is asymptomatic, flat and not thickened, and appears similar to an ephelis (freckle) of skin. The Nevi of Oral cavity are rare and are usually seen in the Hard palate or gingiva. A lesion which appears similar to Oral Nevi is the Amalgam Tattoo and also another Malignant lesion called Melanoma. Orla Nevi cannot be differentiated from Melanoma and hence it is important to either perform a biopsy to confirm or to completely excise the lesion when it is small.