[A pulmonary tumor that racks our brains!]

Area of Science:

• Pulmonology
• Oncology
• Pathology

Background:

• Distinguishing primary pulmonary tumors from metastases is crucial for patient management.
• Meningiomas, typically found in the central nervous system, rarely occur primarily in the lung.

Observation:

• A 74-year-old woman with a history of breast cancer presented with a 2cm lung nodule.
• Initial biopsy immunophenotyping was inconclusive (CK7-, GATA3-, TTF1-, ER+, PR+).
• Surgical resection revealed a well-defined lesion with cohesive cells, intranuclear inclusions, and psammoma bodies.

Findings:

• Immunohistochemistry showed diffuse EMA, SSTR2A, and progesterone receptor expression with a low proliferation index.
• The final diagnosis was primary intra-pulmonary meningioma, with no evidence of intracranial lesions.
• The histopathological diagnosis from biopsy material can be challenging.

Implications:

• This case highlights the importance of considering meningioma in the differential diagnosis of pulmonary nodules with ambiguous histology.
• Early and accurate diagnosis is key for favorable outcomes in rare pulmonary neoplasms.
• Pathologists must be familiar with the diverse presentations of meningiomas.