Background and objective: Sclerosing pneumocytoma is a rare, benign tumor of the lung that represents a diagnostic challenge due to the diversity of pathohistological findings. The aim of this study was to present a 10-year experience with sclerosing pneumocytoma of a large center for the diagnosis and treatment of pulmonary diseases, and to emphasize differential diagnostic dilemmas as a potential source of errors. Material and Methods: This represents a retrospective study of six patients diagnosed and treated with sclerosing pneumocytoma in the 10-year period. The study analyzed various parameters, which are: Sex, age, symptoms, size and localization of the tumor, and its gross and histological features. Results: Sclerosing pneumocytoma was more frequently diagnosed in females (83.34%). The patients ranged in age from 38 to 61. Most of the patients (66.66%) were asymptomatic. Two patients underwent a video-assisted thoracoscopic surgery, two patients had a video-assisted minithoracotomy, and two patients underwent a thoracotomy in order to remove the tumor. The tumor was localized in the left lower lobe, in the right upper lobe, and in the right lower lobe in 50%, 33.34%, and 16.66% of patients, respectively. The tumor size ranged from 1 to 2.5 cm. A pathohistological examination of all six cases reported that all four major histological patterns were found in tissue sections: solid, papillary, sclerosing, and hemorrhagic. In all six cases, an immunohistochemical analysis showed positive expression of TTF-1 and panCK in surface epithelial cells, and TTF-1 positivity and panCK negativity in round stromal cells. Conclusions: Sclerosing pneumocytoma is a strictly histological diagnosis supported by clinical and radiological findings and corresponding immunohistochemical methods. Lung pathologists should always keep this tumor in mind, since its spectrum of differential diagnosis is wide, and therefore it can be an important diagnostic pitfall.

Pulmonary hamartomas are usually solitary, nodular benign lesions in the parenchyma of the lung. They are rarely situated in endobronchial areas, and very few cases are reported with the mediastinum. A 56-year-old female patient got a CT-scan conducted due to coughing and breathlessness and was diagnosed with a nodular lesion in the medial mediastinum. The lesion was operated: it measured up to 4 cm in the largest diameter, had a smooth surface, was of rather soft but elastic consistency, and was extirpated. At pathology, on cut section, it was yellowish and lobular, and with a mixture of cartilaginous, fibrous and adipose tissues with some smooth muscle cell fibers and myxoid areas. The diagnosis of pulmonary hamartoma was made with atypical medial mediastinal localization. This rare presentation could pose some differential diagnostic problems in the clinical diagnosis of more frequent primary and metastatic malignant diseases.

Inroduction. Mediastinal ectopic thyroid tissue (ETT) represents a rare entity. Clinically, it can manifest with thyroid gland disfunction or with symptoms and signs caused by compressive effect on the surrounding structures, but in the majority of cases it is an asymptomatic condition and incidental finding. All pathologic processes, including malignancy, that can occur in the orthotopic thyroid gland can also develop in the ETT. Case report. Here we discuss a case of 17-year-old female with incidentaly found mediastinal ETT. Beside ETT, patient had an orthotopic thyroid gland and was euthyroid. During follow up, mild compressive symptoms developed. MRI examination showed non-significant increase of the mediastinal mass volume, but due to its morphological changes, a suspicion of another etiology was raised. A discrepancy between the positive technetium-99m pertechnetate and negative 131 iodine radionuclide imaging of the mediastinal mass was highly suspicious for malignancy. Surgery was performed and the pathologist confirmed that it was a coloid goiter in the mediastinal ETT. Conclusion. Mediastinal ectopic thyroid tissue should be taken into account in the differential diagnosis of mediastinal tumor mass. Increase in size of the mediastinal EET, development of compressive symptoms or suspected malignant alteration requests surgical treatment.