BACKGROUND: Germline mutations in mismatch repair (MMR) genes are found in only about half of clinically diagnosed families with hereditary non-polyposis colorectal cancer syndrome (HNPCC) (or Lynch syndrome). Early identification of gene carriers is essential to reduce cancer incidence and overall mortality. AIMS: Recent evidence indicates an increase in size and number of sebaceous glands following activation of the hedgehog pathway, a crucial signalling pathway for animal development that is aberrantly activated in several types of cancer. Here we sought to assess a possible association between Fordyce granules (FGs-that is, ectopic sebaceous glands on the oral mucosa) and HNPCC. METHODS: A total of 15 members of five different genetically unrelated HNPCC kindreds (MLH1 gene mutation n = 8; undetectable MLH1 protein at immunochemistry n = 4; clinical diagnosis n = 3) and 630 genetically unrelated age and sex matched healthy controls were examined. Following examination of the oral mucosa surface, subjects were categorised as either FGs positive or FGs negative. RESULTS: Evidence of FGs was significantly associated with HNPCC (13/15 (86.7%) affected patients v 6/630 (0.95%) controls; p<0.0001), with a relative risk of 91.0 (95% confidence interval 40.05-206.76). The observed difference remained significant when carriers of germline mutations in MMR genes were considered (8/15 v 6/630; p<0.0001). The most common site for the FGs in HNPCC patients was the lower gingival and vestibular oral mucosa. CONCLUSIONS: Our findings suggest that a previously unrecognised activation of the sebaceous glands system occurs in HNPCC. The observation could be of value for attending physicians in identifying affected families and/or increase the accuracy of the currently available molecular genetics screenings.

Ectopic sebaceous gland: a developmental anomaly.J Cutan Pathol. 2006 Jul;33(7):519-21.

We report the case of a 21-year-old white male with an ectopic sebaceous gland and duct located within the bulb of an anagen hair follicle. This is an incidental finding in one of two biopsies from his chin, performed as part of the workup for a recalcitrant perioral acneiform eruption. The embryogenesis and development of sebaceous glands in human scalp hair follicles are reviewed. To our knowledge, this is the first report of such a developmental anomaly.

Ectopic sebaceous glands in the vagina.Int J Gynecol Pathol. 2005 Apr;24(2):193-5.

We report a case of ectopic sebaceous glands in the upper third of the posterior wall of the vagina of a 49-year-old woman. This is, to our knowledge, the first fully documented case report of their occurrence in the vagina. The review of the literature and possible embryologic origin are discussed.

Endoscopic detection of ectopic multiple minute sebaceous glands in the esophagus. Report of a case and review of the literature.Dig Dis Sci. 1995 Feb;40(2):287-90.

This case report describes a patient with a rare form of ectopic sebaceous glands. The patient was a 53-year-old woman complaining of prolapse of a polyp through the anus who was admitted for polypectomy of the rectal polyp. After polypectomy, esophagogastroduodenoscopy was performed to detect other lesions. Although she had no symptoms from an upper gastrointestinal series, such as dysphagia, heartburn, or epigastric pain, multiple yellow rounded elevated lesions arranged in rows, 0.5 mm in diameter and more than 100 in number were observed in the middle and lower esophagus. Histological examination of the biopsied specimens taken from the lesions endoscopically revealed a structure with the characteristics of a sebaceous gland including an excretory duct.