Successful treatment of hydroquinone-resistant melasma using topical methimazole.

Melasma is an acquired hyperpigmentation skin disorder in sun-exposed areas. It occurs almost exclusively over the face, and is most commonly seen in women. Several depigmenting agents have been used for the treatment of melasma among which hydroquinone has been the most widely used due to its efficacy and safety in short-term use. However, hydroquinone is recently reported to be a cytotoxic and mutagenic compound in mammalian cells and is thus banned in several countries. Hydroquinone ban has caused investigators to search for alternative depigmenting agents for the treatment of melasma in recent years. Methimazole is an antithyroid agent orally used in humans since several decades and has been shown that when applied topically, it inhibits melanin synthesis and causes skin depigmentation in lab animals as well as human subjects. Herein, we report two hydroquinone-resistant melasma patients who were successfully treated with methimazole cream. Application of 5% methimazole cream once daily resulted in significant improvement of melasma in both patients after 8 weeks. The efficacy of methimazole for melasma treatment as well as its advantages over other known depigmenting compounds (non-mutagenicity, non-cytotoxicity and high tolerability profile) suggests that topical methimazole should be added to the armamentarium of anti-melasma treatment.

Genitogluteal porokeratosis: 10 years to make the diagnosis!

Genitogluteal porokeratosis, a relatively rare presentation of porokeratosis of Mibelli, often manifests in an atypical way due to its verrucous appearance that may obscure the characteristic annular keratotic rim. For this reason, misdiagnosis as other common papulosquamous diseases is not uncommon. We report a 44-year-old man with a 10-year-history of slowly progressive pruritic psoriasiform/lichenified plaques over the buttocks. Despite multiple skin biopsies, the lesions were misdiagnosed as psoriasis, lichen simplex chronicus, pityriasis rubra pilaris, and mycosis fungoides, until the last biopsy revealed findings characteristic of porokeratosis. Dermatologists and dermatopathologists should be aware of this rare and unique variant of porokeratosis, which, in addition to the atypical clinical presentation and the occasional misleading histology, may portend a better prognosis in terms of malignant degeneration.

Takayasu disease presenting as malignant pyoderma gangrenosum in a child with relapsing polychondritis.

A 7-year-old Lebanese girl with recently diagnosed relapsing polychondritis had a 1-month history of several painful ulcerations involving her entire body. Skin biopsy was consistent with the diagnosis of pyoderma gangrenosum. She was hospitalized and started on intravenous steroids with partial improvement. During her hospital stay, she developed right wrist drop. Radiologic studies revealed a large aortic aneurysm and an axillary aneurysm compressing the right brachial nerve plexus. Pathology of the resected aortic anyeurism confirmed the diagnosis of Takayasu's arteritis. The patient was started on infliximab therapy with complete resolution of her skin lesions and improvement in hand function.

Acral pseudolymphomatous angiokeratoma of children in an elderly man: report of a case and review of the literature.

Acral pseudolymphomatous angiokeratoma of children (APACHE) is clinically characterized by angiomatous papules that preferentially affect acral areas of children. It is currently believed to be a variant of pseudolymphoma rather than angiokeratoma. Histopathologically, a mixed inflammatory cell infiltrate comprising B- and T-lymphocytes and a proliferation of thick-walled blood vessels are the hallmark. In the literature, although more adult cases are being described, the clinical, epidemiologic and histopathologic data of this presentation is scant. We report a 76-year-old man who presented with a 5-year history of progressively increasing asymptomatic dusky dome-shaped papules and plaques on his upper and lower extremities. Histology was consistent with APACHE. After reviewing all the adult cases in the literature and comparing them to the classical variant in children, we found no significant difference warranting separating these two variants. We prefer the designation "papular angiolymphoid hyperplasia" to APACHE as it encompasses all the childhood and adult cases involving acral and nonacral sites and highlights the histological and sometimes clinical similarities this entity shares with angiolymphoid hyperplasia with eosinophilia.