|LETTER TO EDITOR
|Year : 2019 | Volume
| Issue : 2 | Page : 187-188
Eruptive vellus hair cysts in a child
Vikrant A Saoji1, Kinjal Deepak Rambhia2, Mayank M Goyal3
1 Department of Dermatology, Jawaharlal Nehru Medical College, Sawangi, Wardha, Dr. Vikrant Saoji Skin Clinic, Nagpur, Maharashtra, India
2 Department of Dermatology, Government Medical College, Dr. Vikrant Saoji Skin Clinic, Nagpur, Maharashtra, India
3 Consultant Dermatologist, Dr. Vikrant Saoji Skin Clinic, Nagpur, Maharashtra, India
|Date of Web Publication||29-Mar-2019|
Dr. Vikrant A Saoji
Dr. Vikrant Saoji Skin Clinic, 1st Floor, Midas Heights, Central Bazar Road, Ramdaspeth, Nagpur - 440 012, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Saoji VA, Rambhia KD, Goyal MM. Eruptive vellus hair cysts in a child. Indian J Paediatr Dermatol 2019;20:187-8
An 8-year-old female child presented with asymptomatic lesions on the trunk for 1 year. There was no history of any topical application. There was no history of similar complaints in the family members. Cutaneous examination revealed multiple, discretely placed uniform, monomorphic skin-colored, and few hyperpigmented tiny papules on the anterior portion of the trunk [Figure 1]. There was no evidence of punctum, follicular opening, discharge, or suppuration in the lesions. The general examination was within normal limits. There were no systemic abnormalities. Provisional differential diagnosis of truncal acne, eruptive vellus hair cyst (EVHC), and steatocystoma multiplex (SM) was considered. Histopathological examination revealed a well-defined cyst lined by stratified squamous epithelium that keratinized without the formation of granular layer. The cyst contained lamellated keratin and numerous fine vellus hair shafts [Figure 2]. Hence, a diagnosis of EVHC was made. The patient was explained regarding the benign nature of the condition.
|Figure 2: Cyst with lamellated keratin and numerous fine vellus hair shafts|
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EVHCs are characterized by numerous skin-colored and hyperpigmented dome-shaped papules affecting the trunk and upper extremities. They are usually numerous, but the occurrence of single lesion has also been reported. They may occur at any age but are commonly seen in children and adolescent age group. EVHCs can be sporadic or familial. Familial cases usually appear early in life and show autosomal dominant inheritance. It arises due to occlusion of vellus hair follicle at the level of isthmus, resulting in cystic dilatation of the proximal part which contains the keratotic debris and the vellus hairs. Histopathologically, they are characterized by a cystic structure in the dermis lined by laminated squamous epithelium (keratinization without granular layer) and containing variable number of vellus hair shafts. Different parts of the pilosebaceous unit can give rise to different cysts.
SM present as multiple rounded yellow-colored firm papules over the trunk and upper and lower extremities. They develop due to obstruction of the sebaceous duct, which results in the development of cyst-containing sebum. SM appears when the sebaceous gland becomes active after puberty. Histologically, there is a cyst which shows intricately folded walls composed of stratified squamous epithelium without a granular layer (trichilemmal keratinization). The characteristic feature is the presence of sebaceous glands in or adjacent to the wall. There may be one or more pilar units associated with the cyst, and few lanugo hairs may be seen.
The hair follicle is divided into three parts: the lower portion, extending from the base of the follicle to the insertion of arrector pili; the short middle part, an isthmus, extending from the insertion of arrector pili to the entrance of sebaceous duct; and the upper portion, infundibulum, extending from the entrance of sebaceous duct to the follicular orifice. The infundibulum is lined by surface epidermis which undergoes keratinization with the formation of keratohyalin granules such as skin. The isthmus is lined by outer root sheath which undergoes keratinization without the formation of keratohyalin granules known as trichilemmal keratinization., Hence, a cyst produced by obstruction at the isthmus region (EVHC) will have epithelial lining with trichilemmal keratinization (no keratohyalin granules) with the cyst-containing vellus hair only without sebaceous material. In SM, cysts result from obstruction of the sebaceous duct which is also lined by epithelia which keratinize without keratohyalin granules (trichilemmal keratinization) and contain sebaceous material. Obstruction higher up in the infundibular region (distal to the opening of the sebaceous duct) will result in blockage of both the sebaceous gland and pilar unit and will result in a cyst which shows both types of lining (with and without keratohyalin granules), containing sebaceous material and vellus hairs, a hybrid cyst. Many cases of such hybrid cysts have been reported.
Both the follicular cysts, EVHCs and SM, show considerable clinical and histological overlap. Typically, these lesions are multiple and asymptomatic. Frequently, patients may present with multiple lesions showing histological evidence of EVHCs and SM when biopsies from different lesions were obtained. Similarly, features of both EVHC and SM overlap may be encountered commonly in a single biopsy specimen. Hence, biopsy of just one cyst may not be sufficient to label it as EVHC or SM.
The obstruction of the follicular structure in EVHC could be due to genetic defect in the keratin. EVHC has been reported in association with ectodermal dysplasia, pachyonychia congenita, and trichostasis spinulosa, which also points toward the genetic defect in the keratinization.
The term “hybrid cyst” was originally referred to describe a cyst with upper part showing epidermoid cyst and lower part showing trichilemmal cyst with a distinct difference between the two linings. When left untreated, the lesions may persist indefinitely, and spontaneous regression of the lesions has also been reported.
This case is being reported as frequently papular lesions on the trunk in children and adolescent age group are misdiagnosed and treated as truncal acne. Asymptomatic small lesions of EVHC can be overlooked. Hence, any such lesions which do not respond to the standard treatment modalities of acne must be biopsied to arrive at the correct diagnosis.
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.
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Conflicts of interest
There are no conflicts of interest.
| References|| |
Karadag AS, Cakir E, Pelitli A. Eruptive vellus hair cysts: An alternative diagnosing method. Indian J Dermatol Venereol Leprol 2009;75:537-8.
] [Full text]
Hong SD, Frieden IJ. Diagnosing eruptive vellus hair cysts. Pediatr Dermatol 2001;18:258-9.
Kirkham N. Tumours and cysts of the epidermis. In: Elder DE, Elenitsas R, Johnson BL, Murphy GF, Merritt J, LaPlante M,et al
, editors. Lever's Histopathology of the Skin. 10th
ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2009. p. 791-849.
Kim MS, Lee JH, Son SJ. Hybrid cysts: A clinicopathological study of seven cases. Australas J Dermatol 2012;53:49-51.
Requena L, Sánchez Yus E. Follicular hybrid cysts. An expanded spectrum. Am J Dermatopathol 1991;13:228-33.
Torchia D, Vega J, Schachner LA. Eruptive vellus hair cysts: A systematic review. Am J Clin Dermatol 2012;13:19-28.
[Figure 1], [Figure 2]