Question:

A 56-year old lady presented with a nodular growth over her left ankle for two years. There was no history of trauma. The nodule was not painful. There was no contact bleeding. Its size remained static and she was treated by cryotherapy twice without clinical response.

Eccrine poroma is an uncommon benign skin appendageal tumour originated from sweat ducts. It is most commonly found over the palms and soles, where the density of sweat glands is the highest in the body. Clinically, it appears as an indolent cutaneous nodule that may be erythematous or scaly. A clinical feature that differentiates skin appendageal tumour from common wart is the sign of collarette, in which an epidermal scaly "collar" is found around the rim of tumour. Treatment is by surgical removal.

Common wart can affect any part of the body. Its surface is hyperkeratotic and black dots, representing thrombosed capillaries, can sometimes be seen. Seborrhoeic keratosis can sometimes be itchy and have an inflammatory appearance, which is known as irritated seborrhoeic keratosis. The typical clinical presentation is a pigmented growth with a granular surface and a characteristic "stuck on" appearance. Pyogenic granuloma is a vascular proliferation in response to cutaneous trauma. In acute stage, it appears as fleshy haemangiomatous nodule. In the chronic stage, it can be less fleshy and there may be variable surface scaling. Contact bleeding is usually present as the growth is richly vascularized.