Annular elastolytic giant cell granuloma associated to late-onset X-linked dominant protoporphyria.

X-linked dominant protoporphyria (XLDPP) is a genetic disorder that affects the synthesis of the heme group due to an increase in delta-aminolaevulinate synthase 2 (ALAS2) enzyme activity. Moreover, annular elastolytic giant-cell granuloma (AEGCG) is a rare reactive granulomatous dermatosis, usually associated with actinic damage. An 86-year-old man presented with edematous-erythematous lesions in photoexposed areas of the face and on the dorsum of both hands. Protoporphyrin levels in serum and feces were significantly elevated and a heterozygous frameshift mutation in the exon 11 of the ALAS2 gene: c.1706-1709del (p.Glu569GlyfsX24) was identified. Concomitantly, we observed an annular plaque with raised borders on the back of his right hand, clinically and histologically compatible with a diagnosis of AEGCG. Skin lesions disappeared only upon use of a physical sunscreen. We report two rare photodermatoses in an elderly patient and discuss the significance of dermal elastic fiber damage induced by the XLDPP as a main triggering factor of AEGCG.

Birt-Hogg-Dubé syndrome in a patient with localized fibrofolliculomas and a novel mutation in the FLCN gene.

BACKGROUND: Birt-Hogg-Dubé syndrome (BHDS) is characterized by skin fibrofolliculomas (FF), multiple lung cysts, spontaneous pneumothorax, and renal cancer. Cutaneous lesions are usually distributed over the face, neck, and upper trunk. The presence of FF confined to a circumscribed region of the skin has rarely been reported. CASE REPORT: A 64-year-old woman presented with a 20-year history of asymptomatic skin lesions located on the neck. Multiple skin-colored papules with a clinical plaque-like appearance were confined to the right side of the neck. Histopathological findings were typical for FF, and BHDS was suspected. The novel heterozygous mutation p.Val126SerfsX4 was identified in exon 5 of the FLCN gene. Colonoscopy, abdominal ultrasound, and abdominal thoracic scan revealed no associated pathologies, except for benign renal and hepatic cysts. DISCUSSION: To date, only two cases of localized FF in BHDS have been reported. Mutation analysis was not performed, but the authors considered the lesions to represent a localized variant of BHDS and speculated that this unusual form of the disease may be associated with a lack of visceral involvement as no signs of systemic disease were detected. CONCLUSIONS: We identified the novel germline mutation p.Vall26SerfsX4 as responsible for this aspect of the patient's phenotype, which suggests that alterations in the FLCN gene are also responsible for localized forms of BHDS. Moreover, the localized distribution of skin lesions may be related to a less severe form of the disease.