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
Histopathologic examination of the biopsy showed a dermis full of pigment-laden macrophages and multinucleated giant cells with haphazard arrangement of nuclei. Subjacent to the dermis were hypertrophic PCs. The 2 onionlike corpuscles seen in Figure 3 have approximately 33 and 20 concentric lamellae. The dermal changes represent a foreign body reaction to paint. The enlarged PCs are the likely source of progressive pain and represent a rare condition called PC hyperplasia, sometimes called Pacinian neuroma.
Blue Macule on the Volar Surface of the Left Thumb—Diagnosis. JAMA Dermatol. 2013;149(1):98. doi:10.1001/2013.jamadermatol.415b