Extended exposure to biomass smoke has previously been associated with domestically acquired particulate lung disease in non-smoking, Iranian women [12] and [13], however mediastinal lymphadenopathy was not a feature of these cases and anthracotic plaques
were found in the airways [13]. Extrapulmonary anthracosis is rare, but can present as mediastinal lymphadenopathy mimicking tuberculosis [7] and malignancy [8] and [9]. In the pre-EBUS era mediastinoscopy or transeosophageal endosonography with fine needle aspirate were methods required for diagnosis but can be associated with significant Selleck SRT1720 morbidity [1], [14] and [15] and is only available in cardiothoracic centers. It is possible that pre-EBUS, cases of mediastinal lymphadenopathy in elderly, Asian, non-smokers would have been treated empirically for TB rather than further investigated, as in Case
4. EBUS-TBNA has demonstrated a diagnostic sensitivity of 94% in patients with intra-thoracic tuberculous lymphadenopathy [4] and combined with PCR techniques has allowed rapid identification and targeted treatment of drug-resistant strains [16]. With increasing utilization of EBUS-TBNA for this purpose, alternative diagnoses may be more frequently identified. All cases documented in our series were TB smear, culture and PCR negative, none have developed TB or malignancy on follow-up. Three of our cases were investigated by FDG-PET/CT scanning and increased signal was identified in the anthracotic nodes sampled. Anthracotic lymph nodes selleckchem in the neck [17], hilar region and mediastinum [8] and anthracotic pulmonary nodules [18] have all been reported to display increased FDG uptake on PET scanning. Inflammatory processes are responsible for false positive lymph node status on PET/CT evaluation of early stage non-small cell lung carcinoma, with anthracosis noted as a potential cause [9]. On the basis of the PET/CT imaging and histopathological much findings of granuloma-like
aggregates of anthracotic macrophages, parallels can be drawn with conditions such as sarcoidosis [19]. Increased FDG uptake has been shown in the mediastinal lymph nodes of patients with sarcoidosis [20]. Anthracotic material could provide persistent antigenic stimulation to macrophages with resultant inflammatory activity highlighted on PET/CT. Dust-laden alveolar macrophages have been shown to migrate to mediastinal lymph nodes following inhalation exposure to inorganic dust fibers in animals [21]. This process of clearance may also operate in anthracosis. Importantly, anthracosis presenting as PET/CT positive lymphadenopathy can coexist or mimic other conditions including tuberculosis [8], and non-small cell lung cancer [22]. This exemplifies the importance of rigorous clinical and radiological follow-up with the aim of identifying any co-existing or underlying pathologies. All cases described in this series were followed-up and remained well at 12 months.