Indian Journal of Paediatric Dermatology

CASE REPORT
Year
: 2020  |  Volume : 21  |  Issue : 3  |  Page : 194--196

Eruptive vellus hair cyst: Unveiling the diagnostic features


Rashmi Agarwal, BS Chandrashekar, Prarthana B Desai 
 Department of Paediatric Dermatology, Cutis Academy of Cutaneous Sciences, Bengaluru, Karnataka, India

Correspondence Address:
Dr. Rashmi Agarwal
Cutis Academy of Cutaneous Sciences, Vijayanagar, Bengaluru, Karnataka
India

Abstract

Eruptive vellus hair cyst (EVHC) is a rare developmental abnormality of the vellus hair follicles presenting in children and adolescents as multiple, asymptomatic papules over the chest, axillae, and buttocks. Clinically, it can easily be misdiagnosed as comedonal acne, keratosis pilaris, steatocystoma multiplex, syringomas, milia, lichen nitidus, perforating folliculitis, and molluscum contagiosum. Here, we report a 4-year-old girl who was being treated as a case of steroid-induced folliculitis and was later diagnosed with EVHC based on dermoscopic features and confirmed by histopathological examination. Dermoscopy of EVHC shows the presence of homogenous blue areas, round or oval yellowish structures, with occasional erythematous halos and cystic openings in the epidermis. We report this case to emphasize the role of dermoscopy in early diagnosis of eruptive vellus hair cyst which is a rare condition and can be missed easily. Dermoscopy, being a non-invasive and painless diagnostic tool, can prove to be a useful, particularly in children for differentiating EVHC from its mimickers, thus avoiding the need for biopsy.



How to cite this article:
Agarwal R, Chandrashekar B S, Desai PB. Eruptive vellus hair cyst: Unveiling the diagnostic features.Indian J Paediatr Dermatol 2020;21:194-196


How to cite this URL:
Agarwal R, Chandrashekar B S, Desai PB. Eruptive vellus hair cyst: Unveiling the diagnostic features. Indian J Paediatr Dermatol [serial online] 2020 [cited 2020 Sep 23 ];21:194-196
Available from: http://www.ijpd.in/text.asp?2020/21/3/194/288487


Full Text



 Introduction



Eruptive vellus hair cyst (EVHC) is an uncommon developmental abnormality of the vellus hair follicles occurring in children, adolescents, or young adults as multiple, asymptomatic, skin-colored to reddish-brown papules with or without hyperkeratosis, involving the chest, axillae, and buttocks. Histopathologically, it presents as dermal cysts lined by the stratified squamous epithelium and filled with laminated keratin and multiple vellus hairs.[1] Spontaneous regression without any treatment has been reported, but treatment is usually sought because of cosmetic reasons.[2]

Dermoscopy can prove to be a useful technique, particularly in children for differentiating EVHC from its mimickers and thus avoiding the need for invasive procedures. Dermoscopy of EVHC shows the presence of homogenous blue areas, round or oval yellowish structures, with occasional erythematous halos and cystic openings in the epidermis.[2],[3],[4]

We report a 4-year-old girl with multiple asymptomatic papules over the trunk, diagnosed as a case of EVHC by dermoscopy and further confirmed by histopathological examination.

 Case Report



A 4-year-old girl presented to us with multiple asymptomatic lesions on the chest and axilla of 3-month duration. There was no history of any trauma or fever before the onset of lesions. Initially, there were 2–3 lesions for which desonide 0.05% cream was applied. Physical examination revealed multiple, 1–3 mm, skin-colored to reddish-brown, dome-shaped, firm, hyperkeratotic papules on the chest, axilla, and lateral part of the trunk [Figure 1]a, [Figure 1]b and [Figure 2]. Koebnerization was absent. A diagnosis of steroid-induced folliculitis was made and steroid application was stopped. After 4 weeks, there was increase in the number of lesions. A differential diagnosis of keratosis pilaris, steroid-induced folliculitis, comedones, and EVHC was made. Dermoscopic examination was done using both hand-held dermoscope in the polarized mode (Dermlite 3N) and using video-dermoscope (Fotofinder), which showed the presence of multiple brownish-to-reddish brown, round-to-oval structures, few of which were surrounded by erythematous to brownish halo. Eccentrically placed pores were present in some lesions [Figure 3]a and [Figure 3]b. Blue homogenous areas were also apparent in certain fields. A 4-mm punch biopsy from the lesional area showed the presence of dermal cysts lined by the stratified squamous epithelium, filled with laminated keratin and vellus hair shafts [Figure 4]. Based on the dermoscopic and histopathological findings, a diagnosis of EVHC was made. The child was started on oral isotretinoin 10 mg daily and is on regular follow-up.{Figure 1}{Figure 2}{Figure 3}{Figure 4}

 Discussion



EVHC, first described by Esterly et al. in 1977,[5] is a benign follicular lesion, the exact pathogenesis of which is not known. According to some authors, it is a developmental abnormality of the vellus hair while others consider it to be hamartoma of the pilosebaceous unit. EVHCs may either be familial or sporadic. There is no sex predilection.[1] EVHCs have been reported to occur in children with ectodermal dysplasias, steatocystoma multiplex, and pachyonychia congenita. They most commonly present as multiple, asymptomatic, skin-colored to reddish-brown, 1–4 mm dome-shaped papules with or without hyperkeratosis/umbilication, most commonly involving the anterior chest, axillae, abdomen, and extremities. Face, neck, and groins may also be involved.[1] Due to its rarity and difficulty to distinguish clinically from other skin conditions, it is usually underreported. Other conditions which can present as multiple asymptomatic papules over the chest are comedonal acne, keratosis pilaris, steatocystoma multiplex, syringomas, milia, lichen nitidus, perforating folliculitis, and molluscum contagiosum. Thus, histological examination often becomes essential to differentiate these lesions from EVHC. It shows a cystic structure lined by the stratified squamous epithelium with multiple vellus hair and laminated keratin within the cyst. Occasionally, the cyst may be surrounded by granulomatous inflammation, causing partial destruction of the cyst wall.[1] A rapid diagnostic test using potassium hydroxide preparation showing numerous vellus hair from the expressed contents of the cyst has been described.[6] In case of children, due to parental as well as child anxiety, a noninvasive method of diagnosis is preferred. Dermoscopy, being noninvasive and less time-consuming, has proven to be a child-friendly method in establishing diagnosis of various dermatological disorders in the recent times. Limited reports on dermoscopy of EVHCs are present in the literature with different findings. Alfaro-Castellón et al. reported the presence of round or oval yellowish structures, with occasional erythematous halos and few irregular, radiating capillaries in the periphery.[2] Oiso et al.[4] and Gencoglan et al.[3] described the presence of cystic openings in the epidermis in the lesions of EVHCs by dermoscopy, a feature barely visible to the naked eye. Gencoglan et al.[3] reported the presence of homogeneous blue pattern on dermoscopy of EVHC resembling a bunch of grapes (bunch of grapes sign). This pattern has also been described in other conditions such as blue nevus and trichilemmal cyst.[3] In this case, the various dermoscopic features reported are present.

Thus, the following dermoscopic features can help differentiate EVHCs from other similar conditions:

Presence of multiple brownish, round-to-oval structures with/without erythematous to brownish haloPresence of central/eccentric poresBlue homogenous areasPeripherally arranged radial capillaries (may or may not be present).

The oval brownish structures probably correspond to the dermal cysts with laminated keratin, while the presence of dense keratin in the cysts gives the blue homogenous appearance because of the Tyndall effect. The halo may be because of the surrounding inflammation. The presence of punctum corresponds to the opening of cysts in the epidermis. The presence of these features can help differentiate EVHCs from other conditions with similar clinical presentations, while the presence of oval brownish structures with punctum can help differentiate it from other conditions showing blue homogenous pattern on dermoscopy.

Spontaneous resolution occurs in 25% of cases. It is resistant to treatment. Various treatment modalities used are incision and drainage, topical keratolytic agents (retinoic acid 0.05%, tazarotene cream 0.1%, urea 10% or lactic acid 12%), topical calcipotriene, oral isotretinoin, CO2, or erbium YAG laser ablation.[7]

We report this case to emphasize the role of dermoscopy in early diagnosis of eruptive vellus hair cyst, which is a rare condition and can be missed easily. Dermoscopy, being a non-invasive and painless diagnostic tool, can prove to be a useful, particularly in children for differentiating EVHC from other conditions presenting with asymptomatic papules on the chest and thus avoid the need for biopsy.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References

1Khatu S, Vasani R, Amin S. Eruptive vellus hair cyst presenting as asymptomatic follicular papules on extremities. Indian Dermatol Online J 2013;4:213-5.
2Alfaro-Castellón P, Mejía-Rodríguez SA, Valencia-Herrera A, Ramírez S, Mena-Cedillos C. Dermoscopy distinction of eruptive vellus hair cysts with molluscum contagiosum and acne lesions. Pediatr Dermatol 2012;29:772-3.
3Gencoglan G, Karaarslan IK, Akalin T, Ozdemir F. Trichilemmal cyst with homogeneous blue pigmentation on dermoscopy. Australas J Dermatol 2009;50:301-2.
4Oiso N, Matsuda H, Kawada A. Eruptive vellus hair cysts of the labia majora: Detection of openings of the cysts to the epidermis by dermoscopy. Eur J Dermatol 2013;23:417-8.
5Esterly NB, Fretzin DF, Pinkus H. Eruptive vellus hair cysts. Arch Dermatol 1977;113:500-3.
6Karadag AS, Cakir E, Pelitli A. Eruptive vellus hair cysts: An alternative diagnosing method. Indian J Dermatol Venereol Leprol 2009;75:537-8.
7Haritha K, Parthasaradhi A, Jalu J. Eruptive vellus hair cyst. Indian J Paediatr Dermatol 2016;17:76-8.