Complex sentence: The only exception occurs in cases where anaplastic large cell lung carcinoma (LCLC) is the second component, where a minimum of 10% of the malignant cells must be LCLC before the tumor is considered to be a c-SCLC.
Split into simpler sentences: The only exception occurs in cases where anaplastic large cell lung carcinoma (LCLC) is the second component. In these cases, a minimum of 10% of the malignant cells in the specimen "must" be LCLC before the tumor is considered to be a c-SCLC.