Mastocytoma with negative Darier’s sign

Abstract

Case report. A 4-month-old little girl was first observed due to a lesion of the right arm appeared when aged 1 month and then grown till to its current size. The physical examination (Fig. 1) showed a lesion of about 8 mm, brownish-yellow in color, reminiscent of mastocytoma, but the mother excluded episodes of redness and swelling. We searched then for the Darier's sign, but 3-4 minutes after rubbing the tumor remained almost unchanged (Fig. 2). Then we thought of juvenile xanthogranuloma and told the mother to inform us in case of swelling or significant changes. After 3 weeks the mother called alarmed because on the first day of the seaside, the tumor swelled, with subsequent formation of a blister filled with liquid and at the same time the face and the neckline flushed to return to normal after 10 minutes. The next day (Fig. 3), the tumor presented a crusted lesion that led us to the final diagnosis of mastocytoma.