Pulmonary nodules in patients with primary Sjögren's syndrome: Causes, clinico-radiologic features, and outcomes

Background: Primary Sjögren's Syndrome (pSS) is characterized by an immune-mediated lymphoplasmacytic infiltration of the salivary and lacrimal glands. Pulmonary nodules are not uncommonly encountered in these patients. Methods: We conducted a retrospective computer-assisted search for patients with pSS who were encountered at our institution between 1999 and 2018 and had histologically characterized pulmonary nodule(s)/mass (es) (PNs). Results: Of 41 patients with pSS and PNs, median age was 67 years (IQR, 56–74), 94% were women, and 39% had a smoking history. The PNs proved to be non-Hodgkin lymphoma (NHL) in 16 patients (39%), lung carcinoma in 11 patients (27%), other malignancies in 2 patients (5%), and benign diseases in remaining 12 patients (29%), including 7 with amyloidomas. Patients with NHL were younger (p = 0.006) while smoking exposure was more prevalent in patients with lung carcinoma (p = 0.022). Patients with NHL had a higher number of PNs and more often manifested random distribution, cysts, ground-glass changes and consolidations. Upper and/or mid-lung location, spiculated borders, solitary nodule, increasing size, and higher SUV_mean on FDG-PET scan were associated with lung carcinoma. At the end of follow-up (median 5.9 years), 8 patients (20%) had died and included 5 patients with lung carcinoma; no deaths were observed in the NHL group. Conclusions: The majority of biopsied PNs in patients with pSS were malignant, most commonly lymphomas. Smoking exposure, solitary nodule, and high FDG avidity were more frequently associated with lung carcinoma. The clinical context, CT and ¹⁸FDG-PET are complementary in the evaluation and management of PNs in patients with pSS.