Calcinosis Cutis With Selective Fibroblast Growth Factor Receptor Inhibitors: A Case Report and Review of Literature

Area of Science:

• Oncology
• Dermatology
• Pharmacology

Background:

• Selective fibroblast growth factor receptor (FGFR) inhibitors are novel cancer therapies approved for metastatic cholangiocarcinoma and urothelial carcinoma.
• These targeted therapies can cause dermatologic toxicities, with rare instances of calcinosis cutis and calciphylaxis.
• Hyperphosphatemia, a frequent side effect, is implicated as a predisposing factor for these vascular and cutaneous calcifications.

Observation:

• A 46-year-old woman with metastatic cholangiocarcinoma developed painful, erythematous leg lesions ten days after initiating pemigatinib treatment.
• Laboratory results revealed hyperphosphatemia with normal serum calcium levels.
• A skin biopsy confirmed the diagnosis of calcinosis cutis.

Findings:

• This case highlights pemigatinib-induced calcinosis cutis, a rare but serious adverse event associated with selective FGFR inhibitors.
• Review of 10 similar cases underscores the clinical spectrum, management strategies, and outcomes of FGFR inhibitor-associated calcinosis cutis.
• Effective management involved pemigatinib discontinuation, phosphate binder therapy, and topical corticosteroids, leading to symptom resolution.

Implications:

• Early identification and monitoring of hyperphosphatemia are essential in patients receiving selective FGFR inhibitors.
• Prompt intervention, including dose adjustment or drug cessation and electrolyte management, can mitigate the severity of calcinosis cutis and calciphylaxis.
• Understanding and addressing these rare dermatologic toxicities are critical for optimizing patient care and treatment adherence in FGFR-targeted cancer therapy.