(Continued from page 908)
ANSWER
Molluscum contagiosum in an epidermoid cyst.
DISCUSSION
Molluscum contagious (MC) is a cutaneous infection described by Baterman in 1817. The etiologic agent is a DNA poxvirus. MC has been associated with other lesions like melanocytic nevus and/or epidermoid cyst (EC).1 The first case of MC in an EC was reported by Hodge et al in 1973. They reported a 33-year-old healthy man with a unique single lesion in the right thigh. The clinical diagnosis was an EC. Histology showed a true EC with molluscum bodies in both the wall and cavity. The patient also had a typical MC lesion in the eyelid. They concluded that it occurred as an inoculation of the EC by molluscum viruses.2 Recently, a few more cases had have been reported, but there are still not many examples.3–15 All cases have occurred in healthy HIV-negative patients. The exact pathogenic mechanisms are uncertain. Aloi and Pippione3 in 1985 suggested 2 theories: the first, molluscum virus infects the follicular infundibulum during the formation process of the EC, and the second, molluscum viruses can invade the dermis and infect an already formed EC. Other authors agree with this explanation.4–8
Ive16 in 1985 thought that MC could induce the formation of EC when the virus was inoculated in the follicular infundibulum. Some authors postulate an increased immunoreactivity of the basal follicular keratinocytes in the presence of epidermic growth factor, which induces follicular hyperplasia and cyst formation.6,9,11
Chiu et al15 in 2010 concluded that satellite skin lesions are produced when the MC virus moves from the cyst to the epidermis through a follicular conduct. It is interesting that similar to other reported cases, our case lacked any MC lesions on the cutaneous surface.2,4,5,10,14,15
Additionally, we have seen skin biopsies of MC with pseudocyst formation. Some are due to epidermal invagination, whereas others are artifacts due to faulty specimen orientation leaving a portion of epidermis in the dermis.
In addition, our case is interesting because, although there are several similar reports to date, the entity is still infrequent and there are none from our country. Also, it emphasizes that the clinical presentation in these cases is nonspecific and the definitive diagnosis is made through histopathologic analysis. Importantly, this case is unique in that the clinical lesion was not visible and was detected only by palpation. Most of the previous reports described visible nodular lesions.
ACKNOWLEDGMENTS
The authors thank Carlos Garcia, MD, for his assistance with the drafting of the final version of our manuscript.
Footnotes
The authors declare no conflicts of interest.
REFERENCES
- 1.Cribier B, Scrivener Y, Grosshans E. Molluscum contagiosum: histologic patterns and associated lesions. A study of 578 cases. Am J Dermatopathol. 2001;23:99–103. [DOI] [PubMed] [Google Scholar]
- 2.Hodge SJ, Fliegelman MT, Schrodt R, et al. Molluscum contagiosum occurring in epidermal inclusion cyst. Arch Dermatol. 1973;108:257. [PubMed] [Google Scholar]
- 3.Aloi FG, Pippione M. Molluscum contagiosum occurring in an epidermoid cyst. J Cutan Pathol. 1985;12:163–165. [DOI] [PubMed] [Google Scholar]
- 4.Park SK, Lee JY, Kim YH, et al. Molluscum contagiosum occurring in an epidermal cyst. Report of 3 cases. J Dermatol. 1992;19:119–121. [DOI] [PubMed] [Google Scholar]
- 5.Egawa K, Honda Y, Ono T. Multiple giant Molluscum contagiosa with cyst formation. Am J Dermatopathol. 1995;17:414–416. [DOI] [PubMed] [Google Scholar]
- 6.Hu SC, Chen GS, Tsai KB, et al. Molluscum infestation of an epidermal cyst associated with focal hyperplasia of cyst wall. J Eur Acad Dermatol Venereol. 2009;23:353–355. [DOI] [PubMed] [Google Scholar]
- 7.Phelps A, Murphy M, Elaba Z, et al. Molluscum contagiosum virus infection in benign cutaneous epithelial cystic lesions. Report of 2 cases with different pathogenesis? Am J Dermatopathol. 2010;32:740–742. [DOI] [PubMed] [Google Scholar]
- 8.Kanitakis J. Molluscum contagiosum in an epidermoid cyst. Am J Dermatopathol. 2011;33:638–640. [DOI] [PubMed] [Google Scholar]
- 9.Santos-Anaya R, Beltrán-Grados G. Molusco contagioso: presentación como quiste epidérmico. Dermatol Peru. 2001;11:43–45. [Google Scholar]
- 10.Aldabagh B, Ly MN, Hessel AB, et al. Molluscum contagiosum involving an epidermoid cyst with xanthogranuloma-like reaction in an HIV-infected patient. J Cutan Pathol. 2010;37:282–286. [DOI] [PubMed] [Google Scholar]
- 11.Basak K, Bazak PY, Karadayi K. Molluscum contagiosum in multiple epidermal cyst in an immunocompetent patient. Saudi Med J. 2013;34:319–320. [PubMed] [Google Scholar]
- 12.Fellner MJ, Osowsky MJ. Molluscum contagiosum in an epidermal inclusion cyst on the eyelid. Int J Dermatol. 1979;18:160–161. [DOI] [PubMed] [Google Scholar]
- 13.Ueyama Y, Osamura Y, Shimamura K, et al. Molluscum contagiosum occurring in an epidermal cyst on the eyelid. Light and electron-microscopic studies with literature review. Acta Pathol Jpn. 1985;35:193–198. [DOI] [PubMed] [Google Scholar]
- 14.Hendricks WM, Myers DE, Hu CH. Molluscum contagiosum occurring in an epidermal inclusion cyst. Cutis. 1980;26:180–184. [PubMed] [Google Scholar]
- 15.Chiu HH, Wu CS, Chen GS, et al. Molluscum contagiosum infestation in an epidermal cyst: still infectious? J Eur Acad Dermatol Venereol. 2010;24:81–83. [DOI] [PubMed] [Google Scholar]
- 16.Ive FA. Follicular molluscum contagiosum. Br J Dermatol. 1985;113:493–495. [DOI] [PubMed] [Google Scholar]