Asymptomatic Annular Plaques in a 67-Year-Old Man: Challenge
A 67-year-old man presented with a 3-month history of asymptomatic and expanding annular plaques. His medical history was significant for hepatitis C and prostate adenocarcinoma that had been diagnosed 3 years earlier. Cutaneous examination revealed 3 erythematous annular plaques with necrotic edges located on the left knee, dorsal aspect of his left foot, and lower back (Fig. 1). A biopsy specimen was obtained from the edge of the lower back plaque. The hematoxylin and eosin–stained biopsy showed partial epidermal necrosis with extensive papillary edema, and a superficial and deep perivascular and interstitial infiltrate composed of histiocytes, lymphocytes, and neutrophils (Fig. 2A). Vascular damage was observed in both the superficial dermis and the mid dermis, characterized by fibrin thrombi, extravasation of erythrocytes, and neutrophilic cellular debris (Fig. 2B). In the reticular dermis, there was also focal degenerated collagen surrounded by the granulomatous infiltrate (Fig. 2C). Direct immunofluorescence was negative. Cultures for fungi, bacteria, and mycobacteria were performed, showing negative results. A laboratory evaluation was performed, but no abnormal findings were seen, including complete blood cell count, anti-cyclic citrullinated peptide antibody, rheumatoid factor, anti-neutrophil cytoplasmic antibodies, antinuclear antibodies, SSA/Ro, SSB/La, anti–double-stranded DNA, complement, cryoglobulins, lactate dehydrogenase, serology for Borrelia, hepatitis B virus, and HIV. Hepatitis C virus load was undetectable.