Discussion
CVG is a rare benign condition first described by Alibert in 1837 characterized by proliferation and hypertrophy of the skin of the scalp or forehead. The affected skin then exhibits folds and furrows resembling the cerebral cortex convolutions. Unna introduced the term cutis verticis gyrata in 1907 [2].
This entity was afterward divided into different subtypes: a secondary and a primary form, then the primary form was subdivided into primary essential and non-essential. The primary essential form is the rarest form, characterized by an isolated cutaneous involvement with no associated pathology. It usually begins in adolescence and is more common in men than in women. Typically, as seen in case 1, primary CVG presents as symmetric scalp folds which usually extend anteroposteriorly from the vertex to the occiput and transversally in the occipital region. Terminal hair density is reduced on the folds, but not in the furrows. The primary non-essential form has been described in association with several neuropsychiatric pathologies like mental retardation, epilepsy, microcephaly, schizophrenia, encephalopathy, and other neurological malformations in addition to ophthalmic pathologies such as blindness, strabismus, and congenital cataract, the latter being the most frequent association. In primary non-essential CVG, the associated conditions do not have a clear pathophysiological link with the CVG.
Secondary CVG on the other hand is associated with conditions that may be implicated in modifications of the trophicity of the skin. It is slightly more common than the primary form. It can occur at any age without gender predominance. It is associated with a variety of underlying disorders. It may be caused by general diseases comprise as liver affections, paraneoplastic syndromes, and pachydermoperiostosis or also associated with inflammatory dermatoses most commonly psoriasis and eczema [3]. Furthermore, various associated genetic conditions have been described such as neurofibromatosis, Noonan, Turner, Klinefelter and Ehlers–Danlos syndrome. It may also occur in association with endocrine etiologies, as seen in case 3, such as diabetes mellitus, myxedema, and the most described in the literature is acromegaly [3]. Among iatrogenic causes, treatment with minoxidil or misuses of anabolic substances were reported [4,5].
The pathophysiology of CVG remains unclear. On a structural level, it is suggested that the folds are caused by connective tissue septa formation between the skin and the galea. These septa prevent the expansion of the skin which bulges into folds [6]. In the primary form, an endocrine origin has been postulated as the disease usually manifests in postpubertal males. Cases reported in the literature are sporadic although some familial cases are described suggesting possible genetic factors in primary CVG. The physiopathology in the secondary form remains also unclear especially in general and inflammatory diseases. However, in the physiopathology of endocrine etiology, trophic hormones such as growth hormone (GH) and insulin growth factor 1 (IGF 1) were incriminated to be responsible for skin modifications with collagen thickening and hypertrophy of sebaceous glands.
When performed, histopathology of primary CVG shows normal skin. Thickened connective tissue with hypertrophy or hyperplasia of adnexal structures has also been described. Secondary CVG has variable histology representing the underlying disease. No treatment has proven its effectiveness in this entity. Abstention is the rule in the primary form. In all cases, regular rigorous hygiene of the skin folds and furrows is recommended to avoid maceration and infection. If treatment is requested by the patient because of an anesthetic complaint, medical and/or surgical treatment may be suggested. Surgical treatment seems to be the best option with a regularly reported efficacy. The undermining and relaxation incisions alter the relationship between the skin and the deeper structures and so result in the disappearance of the folds and furrows [7]. Medical treatment includes isotretinoin or systemic steroids. No treatment can prevent a recurrence.
In summary, CVG is a rare disease with mainly anesthetic impact. A rigorous clinical examination with a minimal workup is however required to eliminate a secondary or a primary non-essential form. If aesthetic prejudice is important, surgical treatment can be suggested.