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Starburst hair follicles: A dermoscopic clue for aplasia cutis congenita
Starburst hair follicles: A dermoscopic clue for aplasia cutis congenita Anna Elisa Verzı, MD, Francesco Lacarrubba, MD, and Giuseppe Micali, MD Catania, Italy Key words: alopecia; aplasia cutis congenita; dermoscopy; diagnosis; trichoscopy.
CLINICAL PRESENTATION A 7-year-old girl and a 2-year-old boy presented with 2 roundish alopecic patches of the vertex measuring 10 and 8 mm, respectively (Figs 1, A, and 2, A). The children were otherwise healthy and their parents described the patches as the result of healing of an ulcerative lesion seen at birth.
Fig 1. Aplasia cutis congenita. A, Alopecic patch of the vertex in a 7-year-old girl. B, Dermoscopy showing a roundish patch of scarring alopecia with some telangiectatic vessels. At the periphery, radially oriented, horizontally extending hair follicles (starburst-like) are clearly visible from the bulbs to the follicular ostia under a thin epidermis (arrows).
Fig 2. Aplasia cutis congenita. A, Alopecic patch of the vertex in a 2-year-old boy. B, Dermoscopy showing a similar pattern of Fig 1, B, with visible radially oriented, starburst-like hair follicles (arrows) Insert, Detail of a horizontally extending hair follicle.
From the Dermatology Clinic, University of Catania. Funding sources: None. Conflicts of interest: None declared. Reprint requests: Giuseppe Micali, MD, Dermatology Clinic, University of Catania, A.O.U. ‘‘Policlinico - Vittorio Emanuele,’’ P.O. ‘‘Gaspare
Rodolico,’’ Via S. Sofia 78, 95123 Catania, Italy. E-mail: cldermct@ gmail.com. J Am Acad Dermatol 2016;75:e141-2. 0190-9622/$36.00 ª 2016 by the American Academy of Dermatology, Inc. http://dx.doi.org/10.1016/j.jaad.2016.02.1216
e141
e142 Verzı, Lacarrubba, and Micali
J AM ACAD DERMATOL
OCTOBER 2016
DERMOSCOPIC APPEARANCE In both cases dermoscopy showed a roundish patch of scarring alopecia with no follicular openings and some telangiectatic vessels. At the periphery, radially oriented, horizontally extending hair follicles (starburst-like) were clearly visible under a thin epidermis from the bulbs to the follicular ostia (Figs 1, B, and 2, B). Based on anamnestic, clinical, and dermoscopic data, the diagnosis of aplasia cutis congenita was made.
HISTOLOGIC DIAGNOSIS In the youngest patient a punch biopsy specimen confirmed the diagnosis showing a flattened epidermis and absence of adnexal structures.
KEY MESSAGE Aplasia cutis congenita is a cutaneous malformation, generally involving the vertex, characterized by congenital localized absence of skin, which may represent a form fruste of cranial neural tube defects such as encephalocele/meningocele.1 The defect generally spontaneously heals after birth leaving a patch of scarring alopecia.1,2 Clinically, the ‘‘hair collar sign,’’ consisting of a ring of dark, coarse, thick hairs surrounding the lesion, may be observed.1 In our cases, no hair collar sign was seen, but dermoscopy revealed the presence of radially oriented, horizontal hair follicles surrounding a patch of scarring alopecia, configuring a starburst hair follicles pattern that was more pronounced in the first case. It was less evident in the second case, likely because of the patient’s younger age. An explanation for the starburst phenomenon is that neural tube defects could produce aberrant shearing forces during the formation of the follicles at some point early in development forcing them to point outward, away from the defect.1 The recognition of this pattern may help in the diagnosis where the hair collar sign is not clinically evident and to differentiate aplasia cutis congenita from other forms of localized hair patches of alopecia that show different dermoscopic aspects.3
REFERENCES 1. Drolet BA, Clowry L Jr, McTigue MK, Esterly NB. The hair collar sign: marker for cranial dysraphism. Pediatrics. 1995;96(2 Pt 1):309-313. 2. Neri I, Savoia F, Giacomini F, Raone B, Aprile S, Patrizi A. Usefulness of dermatoscopy for the early diagnosis of sebaceous nevus and differentiation from aplasia cutis congenita. Clin Exp Dermatol. 2009;34:e50-e52. 3. Lacarrubba F, Micali G, Tosti A. Scalp dermoscopy or trichoscopy. Curr Probl Dermatol. 2015;47:21-32.
CLINICAL PRESENTATION A 7-year-old girl and a 2-year-old boy presented with 2 roundish alopecic patches of the vertex measuring 10 and 8 mm, respectively (Figs 1, A, and 2, A). The children were otherwise healthy and their parents described the patches as the result of healing of an ulcerative lesion seen at birth.
Fig 1. Aplasia cutis congenita. A, Alopecic patch of the vertex in a 7-year-old girl. B, Dermoscopy showing a roundish patch of scarring alopecia with some telangiectatic vessels. At the periphery, radially oriented, horizontally extending hair follicles (starburst-like) are clearly visible from the bulbs to the follicular ostia under a thin epidermis (arrows).
Fig 2. Aplasia cutis congenita. A, Alopecic patch of the vertex in a 2-year-old boy. B, Dermoscopy showing a similar pattern of Fig 1, B, with visible radially oriented, starburst-like hair follicles (arrows) Insert, Detail of a horizontally extending hair follicle.
From the Dermatology Clinic, University of Catania. Funding sources: None. Conflicts of interest: None declared. Reprint requests: Giuseppe Micali, MD, Dermatology Clinic, University of Catania, A.O.U. ‘‘Policlinico - Vittorio Emanuele,’’ P.O. ‘‘Gaspare
Rodolico,’’ Via S. Sofia 78, 95123 Catania, Italy. E-mail: cldermct@ gmail.com. J Am Acad Dermatol 2016;75:e141-2. 0190-9622/$36.00 ª 2016 by the American Academy of Dermatology, Inc. http://dx.doi.org/10.1016/j.jaad.2016.02.1216
e141
e142 Verzı, Lacarrubba, and Micali
J AM ACAD DERMATOL
OCTOBER 2016
DERMOSCOPIC APPEARANCE In both cases dermoscopy showed a roundish patch of scarring alopecia with no follicular openings and some telangiectatic vessels. At the periphery, radially oriented, horizontally extending hair follicles (starburst-like) were clearly visible under a thin epidermis from the bulbs to the follicular ostia (Figs 1, B, and 2, B). Based on anamnestic, clinical, and dermoscopic data, the diagnosis of aplasia cutis congenita was made.
HISTOLOGIC DIAGNOSIS In the youngest patient a punch biopsy specimen confirmed the diagnosis showing a flattened epidermis and absence of adnexal structures.
KEY MESSAGE Aplasia cutis congenita is a cutaneous malformation, generally involving the vertex, characterized by congenital localized absence of skin, which may represent a form fruste of cranial neural tube defects such as encephalocele/meningocele.1 The defect generally spontaneously heals after birth leaving a patch of scarring alopecia.1,2 Clinically, the ‘‘hair collar sign,’’ consisting of a ring of dark, coarse, thick hairs surrounding the lesion, may be observed.1 In our cases, no hair collar sign was seen, but dermoscopy revealed the presence of radially oriented, horizontal hair follicles surrounding a patch of scarring alopecia, configuring a starburst hair follicles pattern that was more pronounced in the first case. It was less evident in the second case, likely because of the patient’s younger age. An explanation for the starburst phenomenon is that neural tube defects could produce aberrant shearing forces during the formation of the follicles at some point early in development forcing them to point outward, away from the defect.1 The recognition of this pattern may help in the diagnosis where the hair collar sign is not clinically evident and to differentiate aplasia cutis congenita from other forms of localized hair patches of alopecia that show different dermoscopic aspects.3
REFERENCES 1. Drolet BA, Clowry L Jr, McTigue MK, Esterly NB. The hair collar sign: marker for cranial dysraphism. Pediatrics. 1995;96(2 Pt 1):309-313. 2. Neri I, Savoia F, Giacomini F, Raone B, Aprile S, Patrizi A. Usefulness of dermatoscopy for the early diagnosis of sebaceous nevus and differentiation from aplasia cutis congenita. Clin Exp Dermatol. 2009;34:e50-e52. 3. Lacarrubba F, Micali G, Tosti A. Scalp dermoscopy or trichoscopy. Curr Probl Dermatol. 2015;47:21-32.