Necrotizing Sarcoid Granulomatosis: A Difficult Diagnosis

Abstract

Necrotizing sarcoid granulomatosis (NSG) is a rare systemic inflammatory disease characterized by sarcoid-like granulomas, vasculitis, and necrosis. This case report describes a 40-year-old man from Guinea-Bissau who presented with weight loss, fever, cough, pleuritic chest pain, dyspnea on minimal exertion, and asthenia. Chest computed tomography (CT) revealed a loculated left pleural effusion and lymphadenopathy in the mediastinal, bilateral supraclavicular, and left axillary regions. The initial investigation suggested granulomatous disease with necrosis. Although there was no microbiological evidence of an infectious etiology, pleural and lymph node tuberculosis was presumed due to the patient's origin from a tuberculosis-endemic region. However, the lack of clinical and radiological improvement despite anti-bacillary therapy prompted further investigation. Follow-up imaging revealed a nodular pattern with lymphatic distribution in the left lung, and histopathological analysis of mediastinal lymph nodes and bronchial biopsies showed granulomas with caseous necrosis. Sarcoidosis was considered, but after a multidisciplinary discussion, a final diagnosis of NSG was established. Following the initiation of corticosteroid therapy, the patient experienced significant clinical and functional improvement, culminating in disease resolution. NSG poses a significant diagnostic challenge due to its varied and nonspecific presentation, often mimicking more prevalent granulomatous diseases. This case underscores the importance of considering NSG in the differential diagnosis of granulomatous diseases, particularly in tuberculosis-endemic regions, and highlights the role of immunosuppressive therapy in achieving disease resolution.

Keywords: granulomas; necrotizing sarcoid granulomatosis; sarcoidosis; systemic inflammatory disease; tuberculosis; vasculitis.

Figure 1. Chest radiograph on hospital admission showing left-sided pleural effusion (arrow).

Figure 2. CT scan on hospital admission, transverse plane. Image A shows 4R mediastinal lymphadenopathy (yellow arrow) and an enclosed pleural effusion on the left side (+). Image B, at the level of the carina, highlights the enclosed pleural effusion on the left side (orange arrows).

Figure 3. Thoracoscopy showing pleural effusion (+) and a thick pleural adhesion (arrow).

Figure 4. Follow-up chest CT scan after three months of anti-tuberculosis treatment, transverse plane. Image A shows mediastinal lymphadenopathies (4R and 4L) that remained stable despite the treatment (yellow arrows). Image B reveals a new nodular pattern in the left lung with perilymphatic distribution (orange arrow).

Figure 5. Endobronchial ultrasound bronchoscopy showing granular appearance of the mucosa (arrows).

Figure 6. Follow-up chest CT scan after seven months of corticosteroid treatment. Image A shows reduction in the mediastinal lymphadenopathies (yellow arrows). Image B shows improvement of the pleural thickening (yellow arrow) and persistence of the nodular pattern with perilymphatic distribution predominantly in the left lung (red arrows).