The American Society of Dermatopathology

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Interactive Case Study - April 2020

23-year-old female with tender erythematous nodules over the medial thighs and volar forearms

James J. Contestable, MD, LCDR, MC, USN; Nicholas Logemann, DO, LCDR, MC, USN

Question 1:

A 23-year-old female presented with a 4-month history of many tender erythematous nodules and plaques over the medial thighs and volar forearms that would resolve with post-inflammatory hyperpigmentation over weeks (Figures 1 and 2).  A punch biopsy from the right volar forearm was performed at presentation.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Which of the following is the best diagnosis?