Pulmonary microinvasive small cell carcinoma with an extensive in-situ component identified after photodynamic therapy for 'squamous cell carcinoma in situ': a case report.

To our knowledge, the in situ phase of small cell lung carcinoma (SCLC) has not been reported previously although in situ/pre-invasive lesions are commonly observed in murine models. We report a patient diagnosed with SCLC presenting mostly as carcinoma in situ after photodynamic therapy (PDT) under the diagnosis of bronchial squamous cell carcinoma (SqCC) in situ.