SECTION EDITOR: MARY S. STONE, MD; ASSISTANT SECTION EDITORS: SOON BAHRAMI, MD; CARRIE ANN R. CUSACK, MD; MOLLY A. HINSHAW, MD; ARNI K. KRISTJANSSON, MD; LORI D. PROK, MD
A 34-year-old, right-handed man presented with a 3-year history of a blue macule on the volar surface of his left thumb. The lesion had progressively become more painful and was affecting his work as a professional painter. He reported that he cut his thumb 3 years earlier while using a high-pressure paint sprayer.
Physical examination showed a nearly triangular bluish-gray macule about 1 cm long (Figure 1). A 2-mm punch biopsy specimen was obtained, and on gross examination, it showed a solid dark blue dermis with several 1- to 1.8-mm white, glistening, rice-grain–shaped globules on the distal aspect of the tissue core (Figure 2). Hematoxylin-eosin–stained tissue specimens were also prepared (Figure 3).
Zech L, Nolan N, Norton SA. Blue Macule on the Volar Surface of the Left Thumb—Quiz Case. JAMA Dermatol. 2013;149(1):97. doi:10.1001/2013.jamadermatol.415a