Answer to last month's Clinical Quiz

Question:

This is a 10 years old girl who has been complaining of increasing pimples on face. Her mother is concerned about her early eruption of pimples. She finds them increasing in number and noticeable in the past two years and once they are formed, they never disappear. They are more or less symmetrically involving the centre of face, nasolabial folds and eyelids. There is no irritation and family members are not known to have similar rash.

Answer:
C. Trichoepithelioma

Trichoepithelioma is a benign hamartomatous skin problem that can present as solitary, multiple and familial lesions. The histology of this type of benign growth shows some tendency towards hair differentiation. The familial form, epithelioma adenoids cysticum is an autosomal dominant condition with increased expression in females. The solitary type may develop to as large as 5mm in diameter and it usually presents as an asymptomatic flesh-coloured translucent nodule on the face of an adult. This can be confused with basal cell carcinoma. Multiple types especially the familial form are usually distributed symmetrically, mainly on the face, nasolabial folds, eyelids and cheeks. They are asymptomatic and commence as translucent skin-coloured papules. Skin biopsy of the lesion can easily identify molluscum contagiosum histologically with typical findings of prominent intra-cytoplasmic inclusions and marked basophilic staining in the keratinocytes. Clinically, there will be a small umbilication at the centre of each papule if it is a typical case of molluscum contagiosum and some of them will disappear after minor abrasion. Sebaceous gland hyperplasia is usually found in elderly patients and there is a yellowish hue in colour.