A61-13 Hourglass-Type Thoracic Giant Lipoma in an 18-Year-Old Male

Abstract Introduction Thoracic chest wall masses are a heterogeneous group of lesions that are approximately ten times more likely to be benign than malignant. Multiple types of lesions may present in children and adolescents, with congenital, infectious, or neoplastic etiologies. Intrathoracic involvement is rarely encountered in the pediatric age group, with only 15 cases of pediatric intrathoracic lipomas reported in English literature as of 1982. This report presents a rare case of a giant thoracic lipoma with both intrathoracic and extrathoracic components in an adolescent male. Case This is a case of an 18-year-old male who presented with a slow-growing, painless thoracic mass on the left side, associated with occasional chest tightness on deep inspiration, without other systemic symptoms. Chest computed tomography (CT) revealed a large, fat-attenuated soft tissue mass in the left lateral chest wall between the 3rd and 4th ribs, resulting in intercostal widening and bone deformity without destruction. Both extrathoracic and intrathoracic extensions were identified. Pulmonary function testing and echocardiogram were unremarkable, and evaluation for germ cell tumor markers yielded negative results. Surgical excision of the mass demonstrated a well-encapsulated fatty mass extending from the subcutaneous area through the intercostal muscles into the thoracic cavity. The extrathoracic component measured 18.8 x 17 x 7.5 cm (1,300 grams), and the intrathoracic component measured 12.5 x 7.5 x 4.2 cm (580 grams), with a total combined weight of 1,880 grams. Histopathologic examination confirmed a lipoma with focal intramuscular involvement and myxoid degeneration. Discussion Evaluation of pediatric thoracic masses requires a systematic approach which integrates thorough clinical assessment and imaging. Radiography, CT, and magnetic resonance imaging help determine the lesion’s location, composition, and extent. Adjunct investigations, including spirometry, echocardiogram, and laboratory tests help determine pulmonary function, cardiac involvement, and exclude other etiologies, respectively. Biopsy remains the diagnostic gold standard, and most thoracic masses require surgical excision for definitive management. Although benign etiologies predominate in children, establishing a histopathologic diagnosis is essential to guide treatment and prognosis. This case highlights a rare hourglass-type thoracic lipoma with both intra- and extrathoracic components in an adolescent - a presentation seldom reported in this age group - and underscores the importance of comprehensive evaluation and surgical management in pediatric thoracic masses. Keywords: Thoracic mass, Giant lipoma, Hourglass lipoma This abstract is funded by: None