Mesothelioma Misdiagnosis + Second Opinion

Quick Answer

Mesothelioma is misdiagnosed in up to 20% of cases. Common misdiagnoses: pneumonia, pleural fibrosis, adenocarcinoma, sarcoma. Mesothelioma cells closely resemble other cancers without specialized immunohistochemistry. Get a second opinion at an NCI-designated cancer center with mesothelioma expertise.

Mesothelioma misdiagnosis is common — up to 20% of cases according to specialty pathology studies. The disease is rare (~3,000 US cases/year), and most pathologists never see a case. Mesothelioma cells closely resemble other cancers (especially adenocarcinoma) without specialized immunohistochemistry testing.

Common Misdiagnoses

• Pneumonia or pleurisy — initial symptoms (shortness of breath, chest pain, pleural effusion) overlap. Antibiotic treatment fails to resolve.
• Pleural fibrosis or asbestosis — non-cancerous pleural thickening from asbestos can be mistaken for early mesothelioma.
• Lung adenocarcinoma — most common mesothelioma misdiagnosis. Treatment differs significantly.
• Sarcoma — sarcomatoid mesothelioma can be misdiagnosed as primary sarcoma.
• Reactive mesothelial hyperplasia — benign mesothelial proliferation can be mistaken for mesothelioma.

Why Get a Second Opinion at an NCI Center

An NCI-designated cancer center with mesothelioma expertise will: (1) re-examine the original tissue sample with mesothelioma-specific immunohistochemistry stains (calretinin, WT-1, CK5/6, D2-40, CEA, MOC-31), (2) review imaging with thoracic radiologists experienced in mesothelioma, (3) consider additional biopsies if uncertain. Top mesothelioma centers include Mount Sinai (NYC), MSK, Brigham/Dana-Farber, UCLA Pacific Mesothelioma Center, MD Anderson, Penn Mesothelioma Program, Washington Hospital Center (HIPEC).

Why It Matters Legally

Mesothelioma diagnosis is the foundation of any compensation claim. Trust funds and courts require pathology confirmation. A misdiagnosis (in either direction — incorrectly diagnosed as mesothelioma or missed mesothelioma) affects: (1) treatment (very different protocols), (2) prognosis discussions with family, (3) compensation eligibility.