# Primary Pulmonary Paraganglioma: A Rare Clinical Entity

## TL;DR

This paper presents a rare case of primary pulmonary paraganglioma, emphasizing the challenges in diagnosis and the importance of immunohistochemistry for accurate identification.

## Contribution

The paper adds a new clinical case of sporadic, non-functional pulmonary paraganglioma and highlights diagnostic insights.

## Key findings

- A 60-year-old woman was diagnosed with a rare primary pulmonary paraganglioma after initial misdiagnosis.
- Immunohistochemistry was critical in distinguishing paraganglioma from other similar tumors.
- The case supports the need to consider paraganglioma in the differential diagnosis of pulmonary masses.

## Abstract

Paragangliomas are rare neuroendocrine tumors arising from extra-adrenal paraganglionic cells, with an estimated annual incidence of 2-8 cases per million. Primary pulmonary paragangliomas are exceptionally uncommon and are frequently mistaken for more prevalent pulmonary diseases, leading to diagnostic delays and management challenges. We report the case of a 60-year-old woman who presented with diffuse, non-radiating left-sided chest pain, progressive dyspnea transitioning from Modified Medical Research Council (mMRC) grades 0 to I, and unintentional weight loss over a two-year period. Laboratory investigations were unremarkable. Imaging demonstrated a well-defined mass in the left upper zone on chest radiograph, and contrast-enhanced computed tomography (CT) revealed a smoothly marginated, heterogeneously enhancing soft tissue lesion in the left upper lobe. Bronchoscopic biopsy initially suggested a clear cell neoplasm; however, immunohistochemical analysis demonstrated findings consistent with paraganglioma. The absence of clinical features suggestive of hereditary syndromes supported the diagnosis of a sporadic, non-functional pulmonary paraganglioma. This case underscores the importance of considering paraganglioma in the differential diagnosis of pulmonary masses and highlights the critical diagnostic role of immunohistochemistry in distinguishing this rare entity from morphologically similar tumors.