Paraneoplastic systemic sclerosis: A distinct entity or a mere association - A case report.

Systemic sclerosis (SS) is a multi-systemic rheumatological disorder that progresses to interstitial lung disease (ILD), pulmonary arterial hypertension (PAH), and scleroderma renal crisis. However, the association between systemic sclerosis and malignancies remains unclear. Although many malignancies can cause skin thickening as a paraneoplastic syndrome, the presence of a positive Scl 70 antibody in this case is intriguing. Traditionally, Scl 70 antibodies have been absent in paraneoplastic SS. However, there have been few reports of diffuse SS with Scl 70 positivity in the context of malignancy. Whether it is a coexisting pathology or a paraneoplastic entity remains debatable. Here, we describe the case of a male in his 50's presenting with diffuse systemic sclerosis with Autosomal Dominant Polycystic Kidney Disease (ADPKD) and hypothyroidism with metastatic epithelial neoplasm of unknown primary origin and a positive autoantibody profile for scleroderma. This case highlights a complex association between SS and malignancy. Although the exact mechanism remains unclear, it is crucial for clinicians to be aware of the possibility of malignancy in patients with SS, especially in those with rapid progression or atypical presentation, irrespective of the autoantibody profiles. Early detection and appropriate management can improve patient outcome.