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The lacrimal caruncle, also called the caruncula lachrymalis, is the small triangle-shaped pink bump located in the corner of the eye. Within this type of caruncle are sweat and oil glands called sudoriferous and sebaceous glands. Some accessory lacrimal glands, hair follicles, and tiny pieces of fat are also contained inside this small cutaneous mass. The glands in it secrete a thick whitish oily substance that is sometimes seen in the corner of a person’s eye after sleeping. On each side of the lacrimal caruncle are two tiny openings called lacrimal puncti that suction tears by vacuum each time the blinking motion of the upper eyelid has ended.
At the medial angle of the eye orbit is the canthus, where the lacrimal caruncle is located. This area is also known as the lacrimal lake. A fold in the conjunctiva called the plica semilunaris helps to keep foreign objects out of the eye and forms the mass of the lacrimal caruncle. It also leads into the lacrimal lake that stores the tears that coat the surface of the cornea. The conjunctiva is a mucus membrane that lines the back of the eyelids along with the eyeball, and is the site of the union of the sclera, cornea, and the upper and lower eyelids.
Many different anatomical structures are used by the lacrimal caruncle. The nerve that supplies the small triangular mass is called the intratrochlear nerve. Lymph drainage vessels from the caruncle drain into the submandibulary lymph nodes. Blood is supplied to it from the superior medial palpebral artery. Some striated muscle fibers from the orbicularis oculi, fibroblasts and melanocytes are found in the stroma just under the surface layer of the caruncle.
Several types of tumors may develop in the lacrimal caruncle and spread to the adnexal structures of the eyebrows, eyelids, and the orbit of the eye. The most common type of tumor is the epithelial tumor, followed by the inflammatory tumor and melanocytic tumors. Many of the tumors discovered on the eyebrows and eyelids originate in this caruncle.
Tumors may develop in the lacrimal caruncles that are epithelial, inflammatory, melanocytic, vascular, or lymphocytic in origin. Many of these tumors are found to be benign after a biopsy of the growth has been examined. Treatment for most benign tumors usually requires the surgical removal of the harmless growth. When a malignant tumor is discovered in the caruncle, the submandibular lymph nodes may also be involved. Chemotherapy and an operation to surgically excise the growth may be needed to treat this rare type of cancer.