A Carotid Body Tumour Mimicking Richter's Transformation of Chronic Lymphocytic Leukaemia.

Carotid body tumours (CBT), also called carotid paragangliomas, are highly vascular glomus tumours that originate from paraganglionic cells of the carotid body. They are frequently asymptomatic, insidious, and non-secretory in nature. They typically present as a large, non-tender, pulsatile neck mass. Careful evaluation of a neck mass, with the aid of imaging, is necessary to avoid a misdiagnosis. We herein describe a case of a 77-year-old gentleman with a background of chronic B-cell lymphocytic leukaemia, who was found to have a rapidly enlarging, asymptomatic neck mass along with multiple enlarged lymph nodes in the axillae. Given his past medical history, the preliminary diagnosis was Richter's transformation. However, the characteristic splaying of the internal and external carotid arteries on imaging prompted us to consider the diagnosis of a CBT. The patient was referred to vascular surgeons for surgical excision of the tumour. Histology confirmed that the neck mass was indeed a CBT. Ultrasound-guided core biopsy of the axillary lymph nodes revealed a concomitant Hodgkin-like Richter's transformation. This case exemplifies how we were able to differentiate between a CBT and nodal mass with the aid of various imaging modalities. An accurate diagnosis allows clinicians to deliver the appropriate management; the treatment for CBT is surgical excision, whereas chemotherapy is the first-line treatment for Richter's transformation.