Background <p>This study aims to characterize the clinicopathological and immunophenotypic profile of calcifying fibrous tumor (CFT) occurring in the thoracic cavity, and to elucidate its key diagnostic features for accurate pathological recognition and differential diagnosis.</p> Methods <p>A retrospective analysis was conducted on 7 cases of thoracic CFT (3 in the mediastinum, 2 in the diaphragm, 2 in the lung). Clinical, imaging, histopathological, and immunohistochemical data were reviewed, and patient outcomes were assessed.</p> Results <p>All patients underwent complete surgical excision. The mean patient age was 39 years, with a female predominance (5/7, 71.4%). Most patients were asymptomatic. The tumors presented as solitary, well-circumscribed masses. Histologically, they were characterized by abundant hyalinized collagen fibers, scattered bland spindle cells, variable lymphoplasmacytic infiltrates, and psammomatous/dystrophic calcifications. Immunohistochemically, tumor cells were diffusely and strongly positive for vimentin, with focal weak positivity for SMA and CD34. Markers including STAT6, ALK, and pan-CK were negative. During a mean follow-up period of 31 months, no recurrence or metastasis was observed.</p> Conclusion <p>This study underscores the importance of including CFT in the differential diagnosis of well-circumscribed thoracic masses. Recognition of its pleural origin, classic histologic triad (hyalinized collagen, chronic inflammation, and calcification) along with a characteristic but nonspecific immunoprofile is crucial to avoid misdiagnosis as more aggressive entities and to guide appropriate conservative surgical management.</p>