Rapidly Progressive Pulmonary Nodules in an Immunocompromised Patient With Nonspecific Interstitial Pneumonitis (NSIP)

Abstract

INTRODUCTION: To present a case of multiple rapidly progressive pulmonary nodules in a patient with NSIP and on immunosuppressive medication CASE PRESENTATION: 66 yr old male with a h/o of latent TB treated for 9 months, and NSIP diagnosed by lung biopsy, presented with 5 weeks of worsening dyspnea associated with low grade fevers, night sweats and severe fatigue. Due to progression of the patient's NSIP despite corticosteroids and azathioprine, he was being treated with mycophenolate mofetil while on concomitant trimethoprim/sulfamethoxazole prophylaxis. A chest CT scan on admission (Figure 1) demonstrated multiple new nodules bilaterally, measuring 4mm to 15mm. Serum beta-d-glucan,alpha-galactomannan levels and serum cryptococcal antigen were negative.Bronchoscopy with BAL and transbronchial biopsy was non-diagnostic. Pt was placed empirically on broad spectrum antibiotics. Due to worsening symptoms, a repeat chest CT was performed on hospital day 5, which demonstrated a marked increase in size and number of nodules (Figure 2). The patient was then referred for VATS which revealed diffuse large B-cell lymphoma superimposed on a background of fibrotic NSIP. DISCUSSION: The differential of multiple pulmonary nodules is broad and includes malignant processes, infectious processes, and non infectious causes. For nodules that rapidly progress, the differential diagnosis is more limited and includes infections, highly aggressive malignancies, lymphoid granulomatosis, granulomatosis with polyangiitis, and necrotizing sarcoidosis. Timely pursuit of a surgical lung biopsy is imperative. Our patient had a history of latent TB and was immunosuppressed, which further concerned us for TB or an opportunistic infection. Nodules are not characteristic of NSIP. B-cell lymphomas may be metastatic to the lungs, or of primary pulmonary origin, which accounts for < 0.4% of all lymphomas. Although work-up on our patient failed to detect any lymphoma outside of the chest, we believe our patient's lymphoma was due to metastasis based on the radiographic appearance. Diffuse large B cell lymphomas typically develop in immunocompetent patients in their sixth or seventh decade. Younger patients are usually immunosupressed due to medications such as methotrexate and antilymphocyte globulin,or HIV. Mycophnolate mofetil has been associated with diffuse large B-cell lymphomas involving the CNS, but it has not been reported to be associated with non-CNS lymphomas. Our patient had no evidence of CNS involvement by CSF analysis and neuroimaging.