The American Society of Dermatopathology

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Interactive Case Study - July 2012

Back Nodule

Christine Cole, MD

Question 1:


A 21-year-old male presented to his primary care physician with a lesion on the right lower back that had been present for the past year but had become tender. Physical examination revealed a 2 x 3 centimeter, firm, tender nodule, which was non-fluctuant. The preoperative diagnosis was sebaceous cyst and an excisional biopsy was performed and sent for histopathologic diagnosis.

Figure 1

Figure 2

Figure 3

Which of the following is the best diagnosis?