### Instruction:
Based on the following clinical note, answer the questions below the note and provide text spans from the note that justify the answers. If the answer to a question cannot be determined by the clinical note, use 'NA' as the answer and justification. Keep the answer shot.

### Input:

Note Date: 2023-04-11
Note Text: 51-year-old man was diagnosed with stage IV advanced NSCLC with pleural metastasis in December 2019. He completed six cycles with pemetrexed plus cisplatin. On June 2020, the patient was diagnosed with EGFR T790M mutation, and he started osimertinib on a dose of 80 mg/day.
Twenty-one days later, he presented with several oral blisters and scattered erythematous maculopapular rashes, which rapidly developed into mucosal erosion and general epidermal detachment involving his entire body with exfoliation on his back skin.
Past medical history: Hypertension, Hyperlipidemia
Medications: Lisinopril, Atorvastatin
Allergies: None documented

Questions: Was the patient diagnosed with a genetic mutation?

### Response: Your answer should have exactly 5 paragraphs. Make sure that the first paragraph starts with the word "difficult" and that each paragraph is separated by two new lines.
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