Fordyce Angiokeratoma: An Unusual Localised Form in Childhood

A 13-year-old male presented to the dermatology department with multiple asymptomatic soft papules along the scrotum. His mother recalls the appearance of three to four small dark purplish spots in the scrotum since the first month of life. Since the age of 11, the lesions multiplied along the scrotum, with the pre-existing spots remaining the same in size and colour. He had no symptoms, including itching, pain, or bleeding. There were no other lesions on the rest of his body. He was a previously healthy child, showing normal growth and psychomotor development, with no history of other medical conditions, including dermatological disorders, and no family history of similar lesions or relevant diseases. On examination, multiple purplish papules less than 2 mm in size were seen on both sides of the scrotum (Figure 1). On palpation, they were soft to firm, non-tender, plane papules. There were no lesions along the penile shaft. Perianal examination was normal. Dermatoscopy revealed multiple well-demarcated, round and dark red lacunae, as well as some red lacunae and peripheral erythema (Figure 2). To rule out Fabry disease, an α-galactosidase fluorometric test was performed, which was normal (8.20 nmol/mL/h, reference range 2.40–10.20 nmol/mL/h). Given the patient's age and the absence of other symptoms, no targeted treatment was given, and he was advised to continue monitoring. Angiokeratomas are rare, benign vascular proliferations characterised by secondary epidermal hyperkeratosis, affecting less than 1% of the population [1]. These lesions are categorised into two main types: widespread and localised forms. The widespread form, known as angiokeratoma corporis diffusum, is associated with Fabry disease, in which α-galactosidase A deficiency leads to glycosphingolipid accumulation in endothelial cells, vascular fragility, and angiokeratoma formation [2]. This is a distinctive cutaneous manifestation of the disease, which characteristically manifests in boys during early childhood and predominantly affects the bathing trunk region, although involvement of other sites and mucosal surfaces is also possible [2-4]. Localised forms include angiokeratoma of Mibelli, solitary or multiple papular types, angiokeratoma of Fordyce, and angiokeratoma circumscriptum or neviforme [1-3, 5, 6]. Angiokeratoma of Fordyce (AKF) is the most common subtype, accounting for approximately 14% of all angiokeratomas, with its prevalence increasing with age [1, 7]. AKF primarily affects men and presents as blue to red papules, usually 2 to 5 mm in size, with a scaly surface, most commonly on the scrotum, shaft of the penis, labia majora, inner thighs, or lower abdomen [2, 4]. Some reports suggest that lesions in younger patients tend to be smaller, more erythematous, and less hyperkeratotic compared with older adults who present with larger, darker (blue/black) lesions with overlying scale. They are usually asymptomatic, sometimes with a progressive appearance over years, but may present with pain, pruritus, or bleeding, spontaneously, after intercourse or scratching [1, 2]. Although angiokeratoma can occasionally manifest in infancy or adolescence, it predominantly presents in late adulthood, with a higher incidence observed in the elderly population. Several hypotheses have been proposed regarding its pathogenesis, including decreased venous tissue elasticity, direct damage to dermal capillaries, and chronic localised venous hypertension such as varicoceles, inguinal hernias, epididymal tumours, trauma, or thrombophlebitis [7-9]. However, the exact aetiology remains unclear. There are also reports of genital angiokeratoma following urogenital radiotherapy, hair laser removal, or chronic human papilloma virus infection (in women) [4, 7]. The diagnosis of angiokeratoma is mainly made clinically by inspection. Dermatoscopy helps to differentiate angiokeratoma from morphologically similar lesions and to exclude other important differential diagnoses such as melanocytic nevi, malignant melanoma, verruca vulgaris, seborrheic keratosis, dermatofibroma, verrucous hemangioma, condyloma acuminata, pyogenic granuloma, or lymphangioma circumscriptum [1, 9]. Dark lacunae are the most distinctive feature for dermatoscopic diagnosis of AKF. They are well-defined, round-to-oval, large, red-to-black areas that form a lacunar or multicomponent pattern. This corresponds to dilated vascular spaces (which may be partially or completely thrombosed) in the upper dermis. There is also a whitish veil that corresponds to the acanthotic and hyperkeratotic epidermis [5, 10]. They may also present with erythema as pinkish areas within the lesion, red lacunae corresponding to wide and dilated vascular spaces in the dermis, haemorrhagic crusts, and peripheral erythema [2]. If the diagnosis is not clear clinically, a skin biopsy should be performed to exclude more serious pathologies [10]. Histologically, there is marked dilatation of the papillary dermal blood vessels to form large cavernous channels with overlying epidermal hyperkeratosis and irregular acanthosis [5]. Most patients with angiokeratomas do not require treatment due to their benign and asymptomatic nature, but they should be monitored regularly for any changes or progression [2, 10]. However, they may be considered cosmetically unpleasant by some patients. In these cases, or in patients with bothersome symptoms, there are several treatment options, including surgical excision, cryotherapy, sclerotherapy, rapamycin, electrocoagulation, or laser treatments [1-3, 6, 8]. The authors have nothing to report. According to the policy of the Department of Dermatology, Egas Moniz Hospital, ULS Lisboa Ocidental, case reports do not require formal approval by the Institutional Review Board. This case was conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from the patient for publication of this case and any accompanying images. The authors declare no conflicts of interest. All data generated or analyzed during this study are included in this published article. No additional datasets were generated.