Diagnosis: BRAF inhibitor-induced keratoacanthoma / squamoproliferative eruption
A 58-year-old male presented with multiple rapidly growing skin lesions on the trunk and extremities after four months of vemurafenib therapy for metastatic melanoma. Clinical examination revealed numerous dome-shaped nodules, consistent with a squamoproliferative eruption. This case highlights the association between BRAF inhibitors and the development of keratoacanthomas, emphasizing the need for awareness and careful monitoring in patients undergoing targeted therapy.
A 58-year-old male with a history of metastatic melanoma presented after four months of vemurafenib therapy, complaining of multiple rapidly growing skin lesions. On physical examination, numerous dome-shaped nodules were noted on the trunk and extremities, some exhibiting central ulceration. The lesions varied in size from 1 to 3 cm and were firm to palpation.Multiple lesions: Eruptive keratoacanthomas noted on trunk and extremities.Rapid growth: Lesions developed over a few weeks.Firm texture: Nodules palpated as firm, with some showing ulceration.Skin type: Fitzpatrick skin type II.History of melanoma: Patient previously treated with surgical excision and adjuvant therapy.
The patient reported that the skin lesions began approximately six weeks after starting vemurafenib. He had no significant prior dermatologic history and had undergone surgical resection of a melanoma on the right arm two years prior. His family history was non-contributory, with no known skin cancers. He denied recent changes in medications or significant sun exposure. The patient had been compliant with his vemurafenib regimen, taking 960 mg orally twice daily.Onset: Lesions appeared six weeks after initiating vemurafenib.Prior treatments: Surgical resection for melanoma; no prior skin lesions.Social history: No significant sun exposure; works indoors.Family history: No history of skin cancer or significant dermatologic conditions.Medication compliance: Adhered to vemurafenib regimen.
Acute / First-Line ManagementDiscontinuation of vemurafenib is recommended to halt the progression of lesions.Topical therapies such as 5-fluorouracil cream may be applied to affected areas to aid in lesion regression.Consideration of surgical excision for larger or symptomatic lesions.Workup and Diagnostic ConfirmationSkin biopsy of representative lesions is essential to confirm the diagnosis and rule out other malignancies.Histopathology typically shows features consistent with keratoacanthoma, including keratin-filled craters and atypical keratinocytes.Consider genetic testing for BRAF mutations and RAS mutations, as these may provide further insights into the tumorigenesis associated with BRAF inhibitor therapy.Long-Term ManagementRegular dermatologic follow-up to monitor for new lesions or changes in existing lesions.Education on potential skin side effects of BRAF inhibitors and the importance of sun protection.Consider alternative systemic therapies for melanoma if keratoacanthomas persist or recur.
Keratoacanthoma: Characterized by rapid growth and a central keratin-filled crater; often self-limiting but can mimic squamous cell carcinoma.Squamous Cell Carcinoma (SCC): Often presents as a persistent, scaly lesion; may require biopsy to differentiate from keratoacanthoma.Actinic Keratosis: Precursor lesions with a scaly appearance, typically found on sun-damaged skin; less rapid in growth compared to keratoacanthomas.Basal Cell Carcinoma (BCC): Pearly nodules with telangiectasia; generally slower growing and less likely to ulcerate compared to keratoacanthomas.Drug-induced Eruptions: Various medications can cause eruptions resembling keratoacanthomas; history of recent drug exposure is crucial for differentiation.Cutaneous Horn: Keratin buildup that can resemble keratoacanthomas; usually associated with underlying lesions.
High-Yield PearlsBRAF inhibitors: Can induce rapid-onset keratoacanthomas and squamoproliferative eruptions, which may mimic malignancy.Clinical vigilance: Essential for dermatologists managing patients on targeted therapies; early recognition can prevent unnecessary treatments.Histopathology: Critical for diagnosis; features of keratoacanthoma include central keratinization and atypical keratinocytes.Management: Discontinuation of the offending agent is often the first step in treatment, followed by topical therapies.Patient education: Important regarding the potential skin effects of treatment and the necessity for sun protection.Awareness of drug reactions in patients receiving targeted therapies is crucial for timely diagnosis and management.
Tags: BRAF inhibitor, keratoacanthoma, drug reaction