Systemic sclerosis sine scleroderma with atypical clinical course: a rare case report.

Introduction and importance: Systemic sclerosis (SSc) is divided into three subtypes: limited cutaneous SSc (lcSSc), diffuse cutaneous SSc (dcSSc), and systemic sclerosis sine scleroderma (ssSSc). ssSSc is a rare subtype of SSc that presents with internal organ manifestations but no cutaneous findings. Case presentation: We report the case of a 58-year-old patient with a history of pulmonary hypertension who presented with symptoms of fatigue, inflammatory polyarthritis, and joint swelling. Following a comprehensive clinical examination and laboratory tests, the patient was diagnosed with ssSSc. Clinical discussion: Due to its atypical clinical course, we present this case report, which commenced with idiopathic pulmonary hypertension. Subsequently, after 7 months, the patient presented complaints of polyarthritis with positive antinuclear antibodies. Raynaud's phenomenon was identified 2 months later during the rheumatology clinic examination. Typically, the clinical course encompasses all three features simultaneously, without any gap between them. Conclusion: Diagnosis of ssSSc remains challenging, and it is essential to consider this disease form in all cases involving unexplained fibrotic involvement of the internal organs.