Chemotherapy-related striate melanonychia: a case report

BACKGROUND: Chemotherapy medications are reported to cause discoloration of the nails known as melanonychia. Depending on the nail structure affected and the severity of the insult, the clinical features can be variable. There are a great deal of unreported cases of pigmentary nail changes associated with chemotherapy treatment. By sharing our knowledge, we hope to raise the awareness of these nail changes amongst clinicians. Early recognition is crucial to allay anxiety among patients and avoid any unnecessary investigations. CASE PRESENTATION: We present a case of 36-year-old woman of south Asian origin, who developed dark pigmentation in the left thumb nail during neoadjuvant chemotherapy with 5-fluorouracil, epirubicin, cyclophosphamide, and docetaxel (FEC-D) for triple negative breast cancer. Upon examination, the left thumb nail pigmentation was strikingly linear, uniform, and well demarcated extending from proximal nail fold to free margin. Despite the reassuring clinical features, the patient was understandably anxious that this could be a presentation of acral melanoma and was referred to the plastic surgeons for a nail matrix biopsy. Biopsy reassuringly was reported as melanosis and a diagnosis of striate melanonychia was made. The patient was discharged after 2-year follow-up. CONCLUSION: Chemotherapy medications have improved survival rates and patient outcomes. It is important for clinicians to be aware of the association of melanonychia with certain chemotherapy medications to reduce anxiety and allow successful management of these patients without delay. Striate melanonychia in this patient was felt most likely due to the synergistic effect of chemotherapy drugs compounded with racial predisposition. Chemotherapy agents most likely to have contributed include cyclophosphamide, docetaxel, and 5-fluorouracil.