B43-51 Silent Skin, Significant Lung Disease: Systemic Sclerosis Sine Scleroderma in a 38-year-old Male

Abstract Introduction Systemic sclerosis sine scleroderma (ssSSc) is an uncommon variant of systemic sclerosis, accounting for approximately 10 percent of cases, characterized by the absence of cutaneous manifestations despite potential involvement of visceral organs including the lungs, heart, and gastrointestinal tract. Diagnosis relies on evidence of internal organ involvement, Raynaud phenomenon, and supportive serologic markers such as antinuclear and scleroderma-specific antibodies. Because hallmark skin thickening is absent, recognition is often delayed, complicating timely evaluation. Early diagnosis and initiation of immunomodulatory therapy are critical to mitigate interstitial lung disease and pulmonary hypertension, which are major contributors to morbidity and mortality. Case Presentation A 38-year-old African American male with hypertension presented with a one-year history of progressive exertional dyspnea and intermittent dry cough. He denied smoking or occupational exposures and had previously failed outpatient trials of albuterol and fluticasone. He recalled cold, numb fingers with bluish discoloration during the previous winter but denied skin tightening. On examination, oxygen saturation was 86 percent on room air, improving with 2 L nasal cannula. Digital clubbing was present, and bilateral velcro crackles were heard on lung auscultation. The skin exam was otherwise unremarkable. Bloodwork, including renal function, was normal; ECG and troponin were unremarkable. CT angiography excluded pulmonary embolism. High-resolution CT demonstrated bibasilar honeycombing and cystic changes with superimposed patchy ground-glass opacities. Echocardiography showed severe pulmonary hypertension with preserved left ventricular function. ANA (nucleolar pattern) and anti Scl-70 were positive. Rheumatology evaluation was obtained. Right heart catheterization confirmed mild pulmonary hypertension. Pulmonary function testing was not completed due to functional limitations. He was started on mycophenolate and referred to an ILD center and discharged on 2 L oxygen. Outpatient follow-up noted improvement in dyspnea. Discussion This case illustrates the diagnostic complexity of systemic sclerosis sine scleroderma, particularly when respiratory manifestations precede other systemic indicators. Although nonspecific interstitial pneumonia is the most common radiologic pattern in ssSSc, usual interstitial pneumonia, as seen in this patient, is also recognized. Esophageal involvement is the most frequent visceral manifestation, followed by pulmonary disease including interstitial lung disease and pulmonary hypertension. Serologic positivity, including nucleolar ANA, anti Scl-70, and the presence of Raynaud phenomenon, was essential for diagnosis; anti Scl-70 may predict later skin involvement. Early rheumatology evaluation enabled timely initiation of mycophenolate to limit pulmonary progression. This case reinforces that systemic sclerosis should be considered in all patients with initially diagnosed idiopathic interstitial lung disease, even without classic scleroderma features. This abstract is funded by: None