Epithelial-myoepithelial carcinoma of the lung

Epithelial-myoepithelial carcinoma of the lung is a rare type of lung cancer characterized by a unique biphasic histological pattern, consisting of both epithelial and myoepithelial cells. This tumor is more commonly associated with the salivary glands, but when it occurs in the lung, it presents a distinct clinical challenge due to its rarity and the limited understanding of its behavior and optimal management strategies.

Epidemiology

The exact incidence of epithelial-myoepithelial carcinoma of the lung is difficult to determine due to its rarity. It accounts for a very small percentage of all lung cancers. The disease can affect adults of any age but is more commonly diagnosed in older individuals. There is no clear gender predilection.

Pathophysiology

Epithelial-myoepithelial carcinoma is characterized by a dual population of cells: inner ductal epithelial cells and outer myoepithelial cells. This biphasic nature is critical for diagnosis. The pathogenesis of this tumor in the lung is not well understood, but it is believed to arise from the respiratory epithelium or possibly from submucosal glands within the bronchial tree.

Clinical Presentation

Patients with epithelial-myoepithelial carcinoma of the lung may present with nonspecific respiratory symptoms such as cough, dyspnea, chest pain, or hemoptysis. Due to its slow-growing nature, symptoms may be present for a long period before diagnosis. In some cases, the tumor is discovered incidentally during imaging for unrelated reasons.

Diagnosis

The diagnosis of epithelial-myoepithelial carcinoma of the lung is primarily based on histological examination of the tumor tissue, often obtained through a biopsy during bronchoscopy or surgery. Imaging studies, including chest X-ray, computed tomography (CT) scan, and magnetic resonance imaging (MRI), can help in assessing the tumor's size, location, and potential spread but cannot definitively diagnose the disease.

Treatment

Due to the rarity of this condition, there is no standardized treatment protocol for epithelial-myoepithelial carcinoma of the lung. Treatment options may include surgical resection, which is often considered the primary treatment modality, especially in cases where the tumor is localized. Adjuvant therapies, such as radiation therapy and chemotherapy, may be considered on a case-by-case basis, depending on the stage of the disease, the patient's overall health, and the presence of metastases.

Prognosis

The prognosis for patients with epithelial-myoepithelial carcinoma of the lung varies and depends on several factors, including the stage of the disease at diagnosis, the completeness of surgical resection, and the presence of metastatic disease. In general, early-stage disease that can be completely resected has a more favorable prognosis.

Conclusion

Epithelial-myoepithelial carcinoma of the lung is a rare and unique form of lung cancer that poses significant diagnostic and therapeutic challenges. Due to its rarity, further research and clinical studies are needed to better understand its behavior, improve diagnostic methods, and develop more effective treatment strategies.

NIH genetic and rare disease info

• NIH info on Epithelial-myoepithelial carcinoma of the lung

Epithelial-myoepithelial carcinoma of the lung is a rare disease.