Pleural Sarcoidosis and Occult Lymphatic Anthracosis: An Unu
Sarcoidosis is a chronic multisystemic inflammatory disease of unknown aetiology. Virtually any organ or system can be involved, resulting in a wide range of clinical presentations. Pleural sarcoidosis is rare. Pleural effusion can only be attributed to pleural sarcoidosis in the presence of pleural non-caseating epithelioid granulomas and after excluding other granulomatous diseases. Anthracosis is a pneumoconiosis associated with thoracic adenopathies and bronchial disease, and it is usually asymptomatic. The authors present a case of a middle-aged man hospitalized due to cough, right-sided pleuritic chest pain and trepopnoea.

A 49-year-old black man with a past medical history of hypertension presented with a 2-week history of cough, right-sided pleuritic chest pain, and trepopnoea. He had occupational exposure to dust as a construction worker, with no other hazardous environmental exposure or smoking history. Arterial blood gas assessment revealed type I respiratory failure. A chest radiograph showed a large right-sided pleural effusion (PE).

Blood analysis showed a normocytic anaemia, an elevated erythrocyte sedimentation rate (ESR; 117mm/h), normal calcium and angiotensin-converting enzyme levels. Thoracocentesis revealed a paucicellular yellow fluid biochemically compatible with an exudate. A transthoracic echocardiogram was unremarkable.

CT confirmed the large right-sided PE and revealed multiple bilateral hilar and mediastinal adenopathies. Pleural biopsy identified the presence of non-caseating epithelioid granulomatosis compatible with pleural sarcoidosis

Flexible bronchoscopy revealed normal bronchial mucosa and echoendoscopy confirmed the presence of multiple hypoechoic mediastinal adenopathies. Histological analysis showed lymphatic tissue with marked sinus histiocytosis and histiocytes with abundant anthracosis pigment. Overall, the study excluded infective, tumoral or auto-immune conditions.
Based on the above-mentioned results, the diagnosis of pleural sarcoidosis associated with lymphatic anthracosis was established. Due to the relapse of the PE and symptomatic deterioration, the patient was started on prednisolone 40 mg once-daily with the resolution of the effusion. To assess disease activity, he underwent a positron emission tomography scan, while already under steroid therapy, which demonstrated mild inflammatory activity within multiple lymph nodes compatible with the diagnosis.

The aetiological investigation of PE should be systematic and exhaustive. Pleural involvement in sarcoidosis is extremely rare, and therefore, a high degree of suspicion is needed, especially in the absence of findings suggestive of pulmonary sarcoidosis. This diagnosis should be suspected whenever the initial investigation is inconclusive. Anthracosis manifests in the presence of endobronchial disease or complications associated with mediastinal adenopathy.