Symptomatic Sclerosing Pneumocytoma of Lung: A Diagnostic Challenge with Diverse Morphological Patterns.

Background & Objective: Sclerosing pneumocytoma (SP), formerly termed sclerosing hemangioma, is a rare benign lung neoplasm often detected incidentally. Its histological diversity and dual cell population frequently complicate diagnosis, particularly in small biopsies. Case Presentation: We describe a 22-year-old female presenting with cough, right-sided chest pain, and dyspnoea for three months. Imaging revealed a well-defined, heterogeneously enhancing right middle lobe mass. Clinical and radiological impressions favored bronchial adenoma or carcinoid tumor. CT-guided biopsy suggested adenoma/adenocarcinoma due to papillary features and mild atypia. Right middle lobectomy revealed a circumscribed, tan hemorrhagic tumor. Histology demonstrated classic SP morphology with papillary, solid, sclerotic, and hemorrhagic patterns and dual surface/round cell populations. Immunohistochemistry showed nuclear TTF-1 positivity, CK7 positivity in surface cells, low Ki-67, and negative chromogranin, excluding carcinoid. No evidence of nodal or distant disease was identified, and the patient remains asymptomatic post-operatively. Conclusion: This case underscores the diagnostic challenges of SP and highlights the role of surgical resection in establishing definitive diagnosis.