Oral hyperpigmentation as an initial clinical aspect of hand foot syndrome

Hand-foot syndrome (HFS) is a common adverse effect of anticancer therapy. It is known to cause dermatological symptoms including acral erythema and dysesthesia of the palms and soles of the feet, swelling, pain, itching, and scaling. Some drugs, like capecitabine, are known to trigger this condition. However, pigmentation of the oral mucosa is a rare adverse effect. This study aims to report a case of oral mucosa hyperpigmentation caused by capecitabine therapy before the clinical diagnosis of HFS. A 58-year-old female, diagnosed with invasive breast duct carcinoma, had the central nervous system, liver, skin, and lung metastasis, using capecitabine every day for 14 cycles. Oral examination revealed multifocal black macules on the hard palate, bilateral buccal mucosa, gingival mucosa, and dorsum of the tongue. The clinical hypothesis was oral mucosa hyperpigmentation by capecitabine use and only periodic follow-up was necessary. Hyperpigmentation of oral mucosa by capecitabine is a rare consequence of neoplastic therapy and your association with HFS is unclear, and poorly reported. The report of these events is important to alert oncology health teams about the individual tolerance to capecitabine therapy.