Background Sarcoidosis is a multi-system granulomatous disease of uncertain aetiology. It is characterised by bilateral hilar lymphadenopathy. The diagnosis is best supported by the histological evidence of non-caseating granulomas in the affected organ (s). The diagnostic procedures for histological confirmation are invasive and a less invasive approach to diagnostic pathway is warranted.

Objectives The utility of diagnostic value of neck ultrasound was retrospectively evaluated in this study. A histological diagnosis was made by ultrasound guided head and neck core biopsy to confirm clinically and radiologically suspected sarcoidosis.

Methods Following clinical assessment by a respiratory physician, 25 patients were referred for sonographic evaluation of the head and neck by a thoracic radiologist after CT scan in an attempt to avoid the use of more invasive and expensive tests such as endobronchial ultrasound (EBUS) and mediastinoscopy. Typically these patients had obvious mediastinal adenopathy +/-parenchymal lung disease, but not clinically apparent neck nodes. Where no cervical lymph node suitable for biopsy was seen, the parotid glands were evaluated and biopsied if deemed abnormal. Patients with no suitable lymph nodes and normal parotid glands were returned for consideration of other diagnostic techniques.

Results A diagnosis of sarcoidosis was made in all cases where a core biopsy of cervical lymph nodes (figure 1) was attempted (23 out of 25 patients). It is emphasised that the cervical lymph nodes in this series were not particularly enlarged, short axis dimensions being under 10 mm in the majority of cases biopsied, and that these sub-centimetre short axis lymph nodes did not have any specific sonographic appearances to mark them as pathological. Nevertheless histological examination revealed non-caseating granulomas in all cases. In a further two cases, where no neck nodes were seen, a histological diagnosis of sarcoidosis was made from biopsy of diffusely abnormal parotid gland tissue.

Conclusions Given the clear advantages of cervical diagnosis in terms of invasiveness and economy compared to mediastinal alternatives, it is suggested that where the expertise for core biopsy of normal sized cervical lymph nodes is readily available, the technique may be considered as a first line investigation for the diagnosis of sarcoidosis.