Non-Infectious Granulomatous Lung Disease: Imaging Findings with Pathologic Correlation

Noninfectious Granulomatous Lung Disease: Radiological Findings and Differential Diagnosis

Granulomatous lung diseases (GLDs) are a heterogeneous group of pathological entities that can have different clinical presentations and outcomes. Granulomas are histologically defined as focal aggregations of activated macrophages, Langerhans cells, and lymphocytes, and may form in the lungs when the immune system cannot eliminate a foreign antigen and attempts to barricade it. The diagnosis includes clinical evaluation, laboratory testing, and radiological imaging, which especially consists of high-resolution computed tomography. bronchoalveolar lavage, transbronchial needle aspiration or cryobiopsy, positron emission tomography, while genetic evaluation can improve the diagnostic accuracy. Differential diagnosis is challenging due to the numerous different imaging appearances with which GLDs may manifest. Indeed, GLDs include both infectious and noninfectious, and necrotizing and non-necrotizing granulomatous diseases and the imaging appearance of some GLDs may mimic malignancy, leading to confirmatory biopsy. The purposes of our review are to report the different noninfectious granulomatous entities and to show their various imaging features to help radiologists recognize them properly and make an accurate differential diagnosis.

Necrotizing sarcoid granulomatosis simulating pulmonary malignancy: A case report

RATIONALE

Necrotizing sarcoid granulomatosis (NSG) has recently been termed "sarcoidosis with NSG pattern" for the disease entity representing nodular sarcoidosis with granulomatous pulmonary angiitis. It is characterized by sarcoid-like granulomas, vasculitis, and a variable degree of necrosis. Its rarity and nonspecific clinical symptoms can easily lead to misdiagnosis or delayed diagnosis.

PATIENT CONCERNS

We report a 67-year-old female with a biopsy-confirmed sarcoidosis with NSG pattern mimicking pulmonary malignancy on initial chest computed tomography scan.

DIAGNOSES

Sarcoidosis with NSG pattern.

INTERVENTIONS

The patient underwent video-assisted thoracoscopic surgery with a lung biopsy. No further treatment was performed after the lung biopsy.

OUTCOMES

Follow-up imaging studies revealed spontaneous regression of the disease after 2 months.

LESSONS

Awareness of this rare benign disease entity and overlapping radiologic manifestations with pulmonary malignancy or other granulomatous diseases can be helpful for making a precise diagnosis with a better differential diagnosis.