Xanthogranulomas are the most common form of non-Langerhans cell histiocytosis. Both adult and childhood forms have been described. Adult cutaneous forms can present as solitary or multiple yellowish, orange-red or tan-hued papules. Herein, we present the case of a 28-year-old Chinese man with a skin-coloured nodule on his left nasal ala that persisted for several months. While initial impression was that of a fibrous papule of the nose, the results of an excision biopsy showed histological features corresponding to xanthogranuloma. This case demonstrates the condition’s myriad of dermatological presentations, and adds to the differential diagnoses of a cutaneous lesion found in the head and neck region.
Adult ; Biopsy ; Diagnosis, Differential ; Granuloma ; diagnosis ; surgery ; Histiocytosis ; diagnosis ; Humans ; Male ; Skin ; pathology ; Skin Diseases ; diagnosis ; surgery ; Treatment Outcome

INTRODUCTION: Pityrosporum folliculitis (PF) is a common skin condition that can be easily misdiagnosed, especially by non-dermatologists. While the initial diagnosis is often made clinically, skin microscopy may help to confirm the same. However, there is scant literature regarding the clinical epidemiology of PF. To our knowledge, in Singapore, only one prior epidemiological study was performed in 1987. Through the present study, we aimed to provide an update regarding the epidemiology, diagnosis and treatment of patients with PF in Singapore. METHODS: We performed a retrospective review of patients with clinical presentations compatible with PF who presented to the dermatology clinic at the National University Hospital, Singapore, between 1 January 2011 and 31 December 2015. The medical records of patients identified as having clinical presentations that resembled PF were reviewed via written and electronic databases. Information regarding the demographics and clinical presentation of the patients was collected. RESULTS: Of the 375 patients identified, 214 (57.1%) were confirmed as having PF based on Gram-stain microscopy. Most (35.0%) of these 214 patients were aged between 21 and 30 years, with a male-to-female ratio of 3:1. The lesions predominantly occurred on the trunk and the back. The majority of patients presented with symptoms that lasted more than one month. 128 (59.8%) patients received oral antifungal treatment, whereas 82 (38.3%) patients were treated with topical antifungal treatment alone. CONCLUSION A typical Singapore patient with PF is a young man aged 21-30 years, with erythematous follicular papules or pustules over the trunk and the back.