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Photo Quiz

Painless Black Toe

Nolan E. Lee, MD, MPH
Arielle Ilano, BA
Ha Kirsten Do, MD, MA
Maylynn Tam, DPM

American Family Physician. 2024;110(6):635-636.

Author disclosure: No relevant financial relationships.

NOLAN E. LEE, MD, MPH, Kaiser Permanente San Jose Medical Center, California

ARIELLE ILANO, BA, University of California School of Medicine, San Francisco

HA KIRSTEN DO, MD, MA, and MAYLYNN TAM, DPM, DABFAS, Kaiser Permanente San Jose Medical Center, California

Address correspondence to Nolan E. Lee, MD, MPH, at nolan.lee@kp.org.

Author disclosure: No relevant financial relationships.

  1. 1.Phan A, et al. Dermoscopic features of acral lentiginous melanoma in a large series of 110 cases in a white population. Br J Dermatol. 2010;162(4):765-771.
  2. 2.Benati E, et al. Clinical and dermoscopic clues to differentiate pigmented nail bands. J Eur Acad Dermatol Venereol. 2017;31(4):732-736.
  3. 3.Ohn J, et al. Developing a predictive model for distinguishing invasive nail unit melanoma from nail unit melanoma in situ. J Eur Acad Dermatol Venereol. 2021;35(4):906-911.
  4. 4.André J, et al. Pigmented nail disorders. Dermatol Clin. 2006;24(3):329-339.
  5. 5.Baran LR, et al. Non-melanoma Hutchinson’s sign. J Eur Acad Dermatol Venereol. 2018;32(3):495-501.
  6. 6.Levit EK, et al. The ABC rule for clinical detection of subungual melanoma. J Am Acad Dermatol. 2000;42(2 pt 1):269-274.
  7. 7.Thai KE, et al. Nail apparatus melanoma. Australas J Dermatol. 2001;42(2):71-81.
  8. 8.Kolla AM, et al. Acral lentiginous melanoma. Cancer Control. 2021;28 : 10732748211053567.
  9. 9.Cutaneous Melanoma: Etiology and Therapy. Codon Publication; 2017.
  10. 10.Labib A, et al. Skin manifestations of diabetes mellitus. Endotext. MDText.com, Inc; 2000.
  11. 11.Cao Y, et al. Longitudinal melanonychia. Chin J Plast Reconstr Surg. 2021;3(1):56-62.
  12. 12.Frazier WT, et al. Onychomycosis. Am Fam Physician. 2021;104(4):359-367.
  13. 13.Higgins JC, et al. Diagnosing common benign skin tumors. Am Fam Physician. 2015;92(7):601-607.

The editors of AFP welcome submissions for Photo Quiz. Guidelines for preparing and submitting a Photo Quiz manuscript can be found in the Authors' Guide at https://www.aafp.org/afp/photoquizinfo. To be considered for publication, submissions must meet these guidelines. Email submissions to afpphoto@aafp.org.

This series is coordinated by John E. Delzell Jr., MD, MSPH, associate medical editor.

A collection of Photo Quiz published in AFP is available at https://www.aafp.org/afp/photoquiz.

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