Rare coexistence of sarcoidosis and lung adenocarcinoma

CASE: An eighty year old African-American female was evaluated for cough, chest pain, asymptomatic anemia and 21 pound weight loss over a six month period. Computerized tomography (CT) revealed a spiculated 2.8 cm right upper lobe lung nodule, other smaller nodules and lymphadenopathy. Gallium scan revealed abnormal uptake of radiotracer in lacrimal, hilar and mediastinal glands. Broncho-alveolar lavage showed CD4/CD8 ratio of 2:1 with 15% lymphocytes. Biopsy of right upper lobe lesion and mediastinoscopic lymph node biopsy showed numerous matured uniform non-caseating granulomatous inflammation, however stains and culture for Acid fast bacilli (AFB)/fungal organisms were negative. Patient improved on oral steroids. Six months later she returned with worsening dyspnea and chest X-ray showed bilateral pleural effusions. Thoracocentesis revealed Thyroid transcription factor 1 (TTF1) positive adenocarcinoma cells and Video assisted thoracic surgery (VATS) procedure revealed numerous pleural, pericardial, diaphragmatic metastasis. Biopsy also was positive for TTF1 adenocarcinoma and positive for Epidermal Growth Factor receptor (EGFR) mutation, however negative for Anaplastic Lymphoma Kinase (ALK). Talc pleurodesis was performed. She was treated with erlotinib while steroid was kept on hold. Initial tumor burden decreased but follow-up PET scan six months later showed progression of tumor with lymphadenopathy. After discussion with patient and family, patient opted for hospice care. DISCUSSION: Oncocentric theory postulates sarcoidosis as an immunological reaction to dispersal of tumor antigen. Sarcocentric theory postulates that cell-mediated immune abnormalities induced by sarcoidosis in CD4 and CD8 cells is involved in the onset of lung cancer. Thus considerable controversy exists regarding sarcoidosis and malignancy. In our case, TTF1 adenocarcinoma cells from thoracocentesis suggest peripheral nodules in right upper lobe and lingula were likely metastatic, presenting as malignant pleural effusions. However if noncaseating granulomatous inflammation is expected as an immunological reaction to tumor antigen, it is very interesting to observe that initial tissue biopsy of primary right upper lobe mass and mediastinal lymph nodes showed matured uniform non-caseating granulomatous inflammation and no evidence of adenocarcinoma. This being said, it would be highly unlikely for sarcoidosis to progress to lung adenocarcinoma within six months. This adds further controversy to whether granulomatous inflammation is a precursor to future malignancy or whether this elderly African-American female was predisposed to develop granulomatous inflammation in presence of a tumor antigen. One can also speculate whether repeat tissue sampling from right upper lobe mass would have shown granulomatous inflammation or TTF1 adenocarcinoma. CONCLUSION: While evidence is still lacking regarding association between sarcoidosis and lung adenocarcinoma, it is important for clinicians to exclude metastatic malignancy in patients exhibiting clinical and radiographic findings consistent with sarcoidosis.