Clinicopathological features of pulmonary sclerosing pneumocytoma: analysis of 15 cases in frozen and conventional diagnosis
Objective: Retrospective analysis of pulmonary sclerosing pneumocytoma and clinical pathological features of the organization to improve the accuracy of frozen section diagnosis. Methods: Retrospectively analyzed 15 patients with surgically resected and diagnosed as pulmonary sclerosing pneumocytoma and 2 cases of frozen misdiagnosed as other lesions of pulmonary sclerosing pneumocytoma, including frozen and routine sectioning, immunohistochemical staining, summarized with clinical pathological features. Results: The group of 15 cases of pulmonary sclerosing pneumocytoma, 13 females, mean age 46 years; 6 cases of lung cancer, 9 cases of other benign lesions; frozen section diagnosis of 6 cases of pulmonary sclerosing pneumocytoma, 1 case of inflammatory pseudotumor, 1 case of hamartoma, 2 cases of lung cancer, 3 cases of benign lesions, 2 cases of delayed diagnosis; tumor were often mixed with two or more structures from the nipple, hardened, solid, and bleeding. In frozen sections, two kinds of organizational structure were found in 10 cases, three kinds of organizational structure in 4 cases, four kinds of organizational structure in 1 case; round cells TTF-1, EMA (+), the surface of epithelial cells TTF-1, EMA and CK (+), two cell Ki-67 index <2%. Two cases were frozen misdiagnosed as pulmonary sclerosing pneumocytoma, 1 case were confirmed as adenocarcinoma, 1 case as alveolar cell adenoma by paraffin. Conclusion: Pulmonary sclerosing pneumocytoma was easily misdiagnosed as cancer via clinical and radiographic data, the diagnostic accuracy of frozen sections is low. Frozen and paraffin sections often see two or more kinds of organizational structure; in frozen section, when papillary-based it may be misdiagnosed as adenocarcinoma; when solid-based it may be misdiagnosed as carcinoid. Combined with immunohistochemical indicators often can be diagnosed.