PA28 Cutaneous sarcoidosis mimicking molluscum contagiosum

Abstract Cutaneous sarcoidosis is known to be a great mimicker of many dermatological conditions. We wish to highlight a case of cutaneous sarcoidosis imitating molluscum contagiosum. We present a case of a female patient who has been known to our paediatric dermatology service since her first year of life with severe atopic dermatitis. In 2022, aged 15 years, she was clinically diagnosed with widespread molluscum contagiosum due to umbilicated papules and nodules on her trunk and limbs. Treatments with potassium hydroxide and cantharidin were tried and both were unhelpful. In July 2023, dupilumab was commenced by the respiratory team for her severe asthma and it had a beneficial effect on her eczema. In August 2023, alongside the skin lesions suggestive of molluscum contagiosum, verrucous plaques with scale were present that seemed to have developed from the papules and nodules. A 4-mm punch biopsy was taken and the histopathology showed acanthosis and parakeratin in the epidermis. Underlying this was a brisk granulomatous inflammatory infiltrate composed of aggregates of epithelioid histiocytes and prominent multinucleated giant cells. There was a small area of fibrinoid necrosis. No fungi or mycobacteria were identified. The histology was suggestive of sarcoidosis. A multidisciplinary team has been involved and determined she has cutaneous disease only. Lymecycline 408 mg once daily for 2 months and mometasone furoate 0.1% ointment were commenced but the disease continued to progress. We then commenced doxycycline 100 mg daily alongside mometasone furoate 0.1% ointment due to the patient’s strong desire to avoid blood tests. Sarcoidosis is a multisystem granulomatous disorder of unknown aetiology that is rare in the paediatric and adolescent population. The cutaneous presentations of sarcoidosis are wide ranging and there is only one case of sarcoidosis mimicking molluscum contagiosum reported in the literature. The case was a 34-year-old woman with known pulmonary sarcoidosis who presented with nodules on the eyelids (Hall JG, Cohen KL. Sarcoidosis of the eyelid skin. Am J Ophthalmol 1995; 119: 100–1). To our knowledge our case is the first reported adolescent case of cutaneous sarcoidosis presenting as molluscum contagiosum. Although it is an uncommon presentation, it is important to be aware of it as a differential diagnosis in cases of atypical molluscum contagiosum. This case, in addition to its severity and rarity, has proven challenging to manage given the patient’s severe venepuncture phobia.