What Are These Dark Brown Patches on the Sole of a Boy’s Foot?

AUTHORS:
Erika C. Malana, BMSc¹ • Michelle L. Gallagher, DO²

AFFILIATIONS:
¹Medical Student, Michigan State University College of Osteopathic Medicine, East Lansing, Michigan
²Assistant Professor, Department of Pediatrics, Michigan State University College of Osteopathic Medicine, East Lansing, Michigan

CITATION:
Malana EC, Gallagher ML. What are these dark brown patches on the sole of a boy’s foot? Consultant. 2022;62(1):e9-e11. doi:10.25270/con.2021.05.00010

Received January 14, 2021. Accepted January 29, 2021. Published online May 24, 2021.

DISCLOSURES:
The authors report no relevant financial relationships.

CORRESPONDENCE:
Erika C. Malana, BMSc, Michigan State University College of Osteopathic Medicine, 965 Wilson Road, East Lansing, MI 48824 (malanaer@msu.edu)

A 9-year-old boy presented to our clinic with skin discoloration on the sole of his right foot that appeared abruptly 3 weeks prior to presentation. His mother said that the discoloration may have slightly faded since the initial presentation.

A skin examination revealed asymmetric, irregular, poorly demarcated brown patches that were darker than the surrounding skin on the patient’s right plantar surface and plantar surface of his right first toe (Figure 1). The numerous patches ranged in size from 1.5 cm in diameter to 3 × 7 cm. A congenital nevus was also present on the right knee, which was stable from the last examination. The rest of the integumentary examination of the head, face, hands, and left foot were unremarkable.

There were no associated or preceding rashes, pain, pruritis, erythema, or constitutional symptoms. Family history of similar discoloration was negative. At presentation, the patient appeared pleasant, well-developed, well-nourished, alert, and oriented.

Answer and discussion on next page.