P022 The scaly imposter: unveiling syringofibroadenoma

Abstract Syringofibroadenoma is an exceptionally rare benign adnexal tumour characterized by a proliferation of eccrine ductal and keratinocyte structures. This lesion, often misdiagnosed due to its rarity and clinical resemblance to other cutaneous neoplasms, underscores the importance of histopathological correlation in dermatological practice. A 63-year-old man was referred to dermatology by his general practitioner with a persistent, inflamed lesion on the right cheek. Incidentally, during full skin examination, a scaly, erythematous patch was identified on the right lower back. The patient reported no symptoms and was unsure of the lesion’s duration. His medical history was significant for myocardial infarction, atrial fibrillation, hypertension, essential thrombocythemia, Barrett’s oesophagus and heart failure. There was no history of previous skin cancers. Clinical examination revealed an 18-mm erythematous, scaly patch, with small erosions and fine, sharp telangiectasia on dermoscopy. A preliminary diagnosis of superficial basal cell carcinoma was made. A 3-mm punch biopsy was performed and was initially reported as an inflamed seborrhoeic keratosis. However, the clinical presentation raised doubts, prompting further histopathological review with deeper tissue sections. The histology revealed a clonal basaloid proliferation of keratinocytes and adnexal cells with focal eccrine duct formation. Notably, there was an absence of the clefting or myxoid change typically associated with basal cell carcinoma. The features were consistent with a syringofibroadenoma. Syringofibroadenoma is perhaps best regarded as reactive eccrine syringofibroadenomatous hyperplasia, as opposed to a tumour, according to the World Health Organization classification of tumours. Since its initial description by Mascaro in 1963, only a limited number of cases have been documented in the medical literature. A 1992 review identified 11 cases up to that time and, comprehensive epidemiological data remain scarce due to the lesion’s rarity. It can present as solitary or multiple lesions, the latter often associated with syndromic conditions such as Schöpf–Schulz–Passarge syndrome. In most nonsyndromic settings, a syringofibroadenoma is considered to be a reactive process. Solitary syringofibroadenomas are often misdiagnosed due to their nonspecific clinical features, frequently mimicking conditions such as basal cell carcinoma, seborrhoeic keratosis or squamous cell carcinoma. Histologically, syringofibroadenoma is characterized by anastomosing cords and strands of basaloid keratinocytes, often connected to eccrine ducts within a fibrovascular stroma. The absence of atypia, clefting or myxoid stroma aids in its differentiation from malignancies. Management is typically conservative, with complete excision performed for definitive diagnosis. This case highlights the diagnostic challenges associated with rare adnexal tumours and emphasizes the role of histopathological examination in confirming clinical suspicions. Awareness of the clinical and histological features of syringofibroadenoma is crucial to avoid misdiagnosis and unnecessary aggressive treatment.