A Proliferating Composite Adnexal Tumour of the Penis: Report of the First Case

Cutaneous adnexal tumours are largely benign lesions, and are typically classified according to their state of appendageal differentiation as eccrine, apocrine, follicular and sebaceous.1,2 However, rare tumours may display a mixture of eccrine, follicular, sebaceous and apocrine differentiation. Such tumours with varied differentiation are relatively rare.3–9 The term “combined adnexal tumours of the skin” was proposed by Apisarnthanarax et al .3 Other synonyms include “benign adnexal tumour with multi-directional differentiation”8 and “benign adnexal tumour of mixed lineage”.1 Clinically, these tumours present as solitary, slowly enlarging dermal or subcutaneous nodules located in the head and neck and in the extremities.1,8 Histologically, they are characterised by well-circumscribed, non-encapsulated nodules composed of a lobular proliferation of epithelial cells displaying a spectrum of eccrine, apocrine, sebaceous and follicular differentiation. We describe a composite adnexal tumour arising in the ventral aspect of the penis, differentiating into follicular and sweat ductal structures. A 40-year-old man presented with an asymptomatic mass over the ventral aspect of the penis that had enlarged over a period of 5 years to a maximum size of 1.5 cm. The mass was excised and sent for histopathological examination. Low-power examination revealed epithelial hyperplasia with hyperkeratosis of the surface epithelium. A relatively well-circumscribed unencapsulated large nodular lesion was seen arising from the epidermis and extending downwards. The lesion was composed of partially solid and partially cystic …