Case
We present a case of multiple clear cell acanthoma in an elderly caucasian man. To our knowledge, this is one of the few cases of multiple clear cell acanthoma that has been reported in the literature.
A 76-year-old gentleman presented with a two-year-history of asymptomatic bilateral inner thigh lesions. There was no relevant past medical history. On examination, the patient had two lesions on his right inner thigh and one lesion on his left inner thigh. On his right inner thigh, there was a pink papule with fine scales that was 5mm in diameter and another pink nodule with yellow crust which was 12mm in diameter. Dermoscopically, the presence of glomerular vessels was noted. On his left inner thigh, there was a 13mm pink nodule with yellow crust.
The initial clinical differential diagnoses that were considered for the right medial thigh lesion were squamous cell carcinoma, amelanotic melanoma and pyogenic granuloma. For the right lateral thigh lesion, differential diagnoses of dermatofibroma, dermal nevus and amelanotic melanoma were considered. Pyogenic granuloma was taken into account for lesion of the left medial thigh lesion.
The two lesions located on the right inner thigh were biopsied. The histopathology report showed parakeratosis, regular acanthosis and prominent clearing of keratinocyte cytoplasm, findings of which are consistent with clear cell acanthoma.
Conclusion
To our knowledge, this is one of the few cases of multiple clear cell acanthoma that has been reported in the literature. Although eruptive clear cell acanthoma is rare, this case highlights the need for consideration of this benign but rare tumour.