Three cases of giant pilomatrixoma - considerations for diagnosis and treatment of giant skin tumours with abundant inner calcification present on the upper body

Background: Pilomatrixoma frequently occurs as a solitary, small tumour on the face or upper extremities of people younger than 20 years. Methods: We report three cases of giant pilomatrixoma. In all these cases, outward appearances and imaging investigations suggested malignant tumours. Preoperative biopsies suggested that case 1 was a basal cell carcinoma, but cases 2 and 3 had no malignant features on biopsy. Two of the cases experienced rare complications e hypercalcaemia caused by parathyroid-related protein (PTHrP) production and multiple occurrences. Results: All three tumours were removed with a 1-3-cm margin. The postoperative histopathologies showed pilomatrixoma in all three cases. Conclusions: Rarely, pilomatrixoma develops to a giant size with various atypical outward appearances consistent with a malignant tumour. Preoperative clinical appearances frequently lead to misdiagnosis, and preoperative examinations are unreliable. Therefore, when a giant tumour with abundant inner calcification is present in a young patient, the possibility of a pilomatrixoma should be considered. (C) 2010 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.