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Int J Clin Exp Pathol 2013;6(9):1890-1893

Original Article
Pigmented pilomatricoma: an underrecognized variant

Mitsuaki Ishida, Hidetoshi Okabe

Department of Clinical Laboratory Medicine and Division of Diagnostic Pathology, Shiga University of Medical Science, Shiga, Japan

Received July 21, 2013; Accepted August 16, 2013; Epub August 15, 2013; Published September 1, 2013

Abstract: The presence of melanin pigment and/or melanocytes in pilomatricoma has been rarely documented. In this study, we analyzed the
incidence and clinicopathological features of pigmented pilomatricoma. Fifty-seven consecutive pilomatricoma cases from 53 Japanese
patients were examined in this study. In fourteen cases (24.6%), pigmentation was observed in pilomatricoma. This variant equally affected in
males and females, and the common locations were the upper arm and face. Proliferation of dendritic melanocytes was observed within
basaloid cell nests in all cases, and melanin pigment was also present within the cytoplasm of the basaloid cells in 11 cases. Melanin
pigment was also present in the shadow cells in 7 cases. The incidence of pigmented pilomatricoma as documented in previous reports is
approximately 10%. However, our analysis revealed that pigmented pilomatricoma was found in 24.6% of Japanese cases of pilomatricoma,
thus, this variant is not uncommon and may be under-recognized. (IJCEP1307036).

Keywords: Pilomatricoma, pigmented, melanocytes

Address correspondence to: Dr. Mitsuaki Ishida, Department of Clinical Laboratory Medicine and Division of Diagnostic Pathology, Shiga
University of Medical Science, Tsukinowa-cho, Seta, Otsu, Shiga, 520-2192, Japan. Tel: +81-77-548-2603; Fax: +81-77-548-2407; E-mail:
mitsuaki@belle.shiga-med.ac.jp