- Commissural Lip Pit
A punctate depression is present at the right labial commissure. (from Color Atlas of Oral and Maxillofacial Diseases)
Commissural lip pits are tiny mucosal invaginations at the corners of the mouth near the vermilion border. Such depressions have been noted in 12% to 20% of the adult population, whereas among children the reported prevalence is only about 0.2% to 0.7%. Although such pits often are considered to be congenital defects, their increased frequency in adult patients suggests that they usually do not appear until later in life. Commissural lip pits occur more often in males than in females.
Commissural lip pits are typically asymptomatic unilateral or bilateral lesions that are discovered as incidental findings. They appear as small punctate depressions extending to a depth of 1 to 4 mm on the lip vermilion at the commissures. Because ducts from minor salivary glands may empty into the depth of the pit, a small amount of mucoid secretion sometimes can be expressed. Commissural lip pits have been associated with a higher prevalence of preauricular pits, but they are not associated with orofacial clefting. Because of their asymptomatic nature, treatment rarely is required. However, if excessive salivary secretions occur or secondary infection develops in a deep pit, then surgical excision may be considered.
- Paramedian Lip Pits and Van der Woude Syndrome
Bilateral pits are seen adjacent to the midline of the lower lip vermilion. (from Color Atlas of Oral and Maxillofacial Diseases)
Same patient as depicted in Fig above with a cleft of the soft palate. (from Color Atlas of Oral and Maxillofacial Diseases)
Paramedian lip pits are rare congenital invaginations that are seen on the vermilion border of the lower lip, lateral to the midline. Such lesions are usually bilateral, although in some instances a single pit may be found more centrally positioned or lateral to the midline. Paramedian lip pits are significant because they usually are associated with van der Woude syndrome, an autosomal dominant condition that also includes cleft lip (CL) and/or cleft palate (CP). Van der Woude syndrome is the most common form of syndromic orofacial clefting, occurring in 1 out of every 40,000 to 100,000 births. It is estimated that 2% of all CL and CP cases are part of van der Woude syndrome, which is caused by mutations of the gene that encodes interferon regulatory factor 6 (IRF6). Some people with paramedian lip pits and van der Woude syndrome may not demonstrate clefting or they may exhibit only a submucosal CP; however, such individuals can transmit the full syndrome to their offspring. Paramedian lip pits also can be a feature of two other syndromes that include orofacial clefting: popliteal pterygium syndrome and Kabuki syndrome.
Paramedian lip pits appear as blind sinuslike depressions that can extend to a depth of 1.5 cm. A humped swelling sometimes surrounds the central pore. Salivary secretions may be expressed because of minor salivary gland ducts that empty into the depth of the pit. If the pits are a cosmetic problem for the patient, then surgical excision can be performed.
这种情况翻译成中文有人叫做“唇窝”，如：高柠, 赵弘. 唇窝,唇裂与腭裂综合征(Van der Woude Syndrome)[J]. 中华整形烧伤外科杂志, 1989, 005(002):98-99，或唇小窝（台湾）。