Primary Anterior Mediastinal Cholesterol Granuloma: A Rare Case in a Young Woman and Literature Review.

BACKGROUND: Mediastinal cholesterol granuloma (MCG) is an exceedingly rare condition, with a limited number of cases reported worldwide. The clinical and imaging characteristics of MCG remain poorly understood and often lead to misdiagnosis. This case report of a young female patient contributes to the literature by summarizing the clinical features, imaging findings, and differential diagnosis of MCG in a demographic category rarely described in previous reports.

CASE DESCRIPTION: A 30-year-old female with a history of community-acquired pneumonia, pulmonary tuberculosis (cured), and syphilis was incidentally found to have an anterior mediastinal mass on imaging. This patient had no history of trauma or other risk factors related to the onset of MCG. Meanwhile, the gender and age characteristics were also different from those commonly seen in the literature. Surgical resection at our hospital confirmed the diagnosis of thymic cholesterol granuloma. Literature review identified 24 reported cases of MCG, predominantly in older males (94.74%; average age, 58.3 years), with a geographic distribution across Europe, East Asia, and North America (36.8%, 31.6%, and 26.3%, respectively). Notably, three of the cases involved young and middle-aged patients with a history of chest trauma. The imaging features varied, with magnetic resonance imaging (MRI) showing low signal (indicating cholesterol crystals) or high signal intensity (due to methemoglobin) on T1/T2-weighted images. Positron emission tomography (PET) scans typically revealed high uptake signals attributed to chronic granulomatous inflammation.

CONCLUSION: MCG is a rare anterior mediastinal lesion with nonspecific imaging features. A history of dyslipidemia or chest trauma combined with compatible imaging findings should prompt consideration of MCG in the differential diagnosis. The possibility of MCG should also be considered in young women with a history of tuberculosis or syphilis. This case highlights the importance of recognizing atypical presentations of MCG to reduce misdiagnoses and guide appropriate management.