26. ANCA-associated vasculitis in a patient with a PET-avid lung lesion

INTRODUCTION: Vasculitis can be a primary or secondary process. Underlying secondary causes include infection, malignancy and other autoimmune conditions. This case describes a patient with findings consistent with ANCA-associated vasculitis. As part of investigations, she was identified as having a PET-avid lung lesion for which she is currently undergoing further investigation via the respiratory team. From a rheumatological perspective she is receiving treatment for her vasculitis, however at present it is unclear whether this is a secondary paraneoplastic phenomenon. This case explores the nature of her presentation and the relationship of primary versus secondary paraneoplastic vasculitis. CASE DESCRIPTION: A 75-year-old lady presented to hospital with a 6-week history of fatigue, pyrexia and myalgia. During this period she additionally noted numbness/neuropathic pains affecting her feet. She had a background of COPD/asthma diagnosed 10 years previously. She had additionally undergone polypectomy for nasal-polyps and had underwent right mastectomy in 1990 for breast cancer. She was noted to have raised inflammatory markers (CRP 256) and eosinophilia. She was deemed to have an infective exacerbation of COPD/asthma although at the time she had limited respiratory symptoms and CXR was reported normal. She was initiated on a 5-day course of prednisolone 40mg and antibiotics. Her symptoms appeared to respond to treatment, as did her CRP and eosinophilia, and she was discharged. Unfortunately she re-presented with similar symptoms within a few days. Further investigation and blood tests demonstrated cANCA antibodies with PR3 of 128 IU. Urine PCR was mildly raised at 30mg/mmol. She was reviewed by the rheumatology team, and likely diagnosis of ANCA-associated vasculitis was made. It was noted however that while her serology was suggestive of granulomatosis with polyangiitis (GPA), her clinical picture of eosinophilia, COPD/asthma and nasal-polyps was more consistent with eosinophilic granulomatosis with polyangiitis (EGPA). She was re-initiated on prednisolone 40mg and demonstrated clinical response. As part of work-up, CT-CAP was arranged. This reported a spiculated lesion of the right-upper lung lobe with appearances concerning for malignancy. Subsequent PET-CT confirmed this be PET-avid, with additional suspicious nodules. She was additionally arranged for nerve-conduction studies regarding her feet symptoms, with findings being consistent with mononeuritis multiplex. From a rheumatological perspective, she has been initiated on azathioprine and prednisolone is gradually being reduced. She has ongoing follow up with respiratory regarding her lung lesion, with initial biopsy being inconclusive. Further attempt at gaining histology is currently awaited. DISCUSSION: From a rheumatological perspective, aspects of this case support a diagnosis of ANCA-associated vasculitis. Presence of cANCA with PR3 antibodies are typically associated with GPA, although her eosinophilia, asthma and previous history of nasal polyps would be more consistent with EGPA. The features of mononeuritis multiplex on nerve conduction studies would also support an underlying diagnosis of vasculitis. Although there is a documented relationship between malignancy and vasculitis, this appears to be relatively rare with a 5-8% association. Haematological malignancies such as lymphoma and MDS have a greater association in comparison to solid tumours. Typical manifestation of paraneoplastic vasculitis is that of cutaneous involvement, particularly of leukocytoclastic vasculitis. Reports suggest improvement of secondary vasculitis on treatment of the underlying condition. With regards to the association of ANCA-vasculitis and solid tumour malignancy, cases appear to be less well-described. The majority of case studies exploring the link between these conditions are primarily in the context of secondary malignancy occurring after immunosuppressive therapy (such as cyclophosphamide) for vasculitis. Review of literature outside of this context, especially in regards of specifically lung malignancy is limited – so a consistent established link may be less apparent. Of the limited studies, interestingly there have been reports of patients with biopsy proven lung malignancy and raised MPO/PR3, with levels normalising following treatment of the underlying lesion. As described in this case, our patient currently awaits further investigation regarding her lung lesion and subsequent review of its definitive intervention. Should investigations confirm malignancy and this be treated, then it would be interesting to see whether there is clinical resolution of her systemic vasculitis secondary to this. KEY LEARNING POINTS: This case demonstrates the presence of 2 conditions of ANCA-associated vasculitis and possible lung malignancy which were both diagnosed during the same admission. Literature suggests possible association between vasculitis and malignancy in a general sense, however specific description of ANCA-vasculitis and lung malignancy has been rarely described. At present, this patient’s vasculitis is being managed whilst definitive intervention is being arranged for her underlying lung lesion. Continued follow up from both the rheumatologists and respiratory team is ongoing and response of her condition will be assessed pending intervention of her underlying lung lesion. CONFLICTS OF INTEREST: The authors have declared no conflicts of interest.