Pilomatricoma with a bullous appearance.

BACKGROUND

Pilomatricoma is a benign, cutaneous neoplasm with differentiation toward hair matrix. The tumor is usually a deep-seated, solitary, firm nodule with overlying normal epidermis. Pilomatricoma with a bullous appearance is very rare.

METHODS

A 16-year-old Chinese girl with a soft, purplish, translucent bulla on the left shoulder for 6 months and a nodule underlying the bulla is described.

RESULTS

The histopathologic findings were consistent with pilomatricoma. There was extraordinary dilation of lymphatic vessels in the overlying dermis, which explains the clinical bullous appearance. The surrounding dermis had an edematous appearance. A Verhoeff-van Gieson stain disclosed the marked reduction of the elastic fibers, and an alcian blue stain was negative.

CONCLUSIONS

The patient is diagnosed as bullous variant of pilomatricoma.