a 58-year - old male patient presented with a one - week history of bloody otorrhea from the right side . in the past 34 years , the patient had undergone four surgeries to remove the masses from his right parotid gland . histopathologic examinations performed after the first three surgeries indicated the presence of benign pleomorphic adenomas . the latest surgery was performed nine months ago to remove a 3.3 cm mass from the parotid gland . following this surgery however , a histopathologic examination revealed a true malignant mixed tumor ( carcinosarcoma ) composed of poorly differentiated carcinoma and osteosarcoma . immunohistochemical studies were positive for p53 , ki67 , and vimentin , weakly positive for cytokeratin , and negative for actin and the s100 protein . the patient was given adjuvant radiotherapy after the latest surgery and was doing well except for symptoms associated with irradiation . the patient underwent a follow - up high - resolution ct scan of the temporal bone for the presented symptoms and showed extensive opacification of the right mastoid air cells , posterior petrous bone , middle ear , and the external auditory canal . excisional biopsy of the external auditory canal mass was performed and confirmed the diagnosis of a recurrent true malignant mixed tumor . during this hospitalization , a chest radiograph indicated the presence of patchy opacities in his left lower lung field ( fig . 1a ) not seen in previous chest radiographs ; this warranted a ct scan for further characterization . a ct scan of the chest showed parenchymal consolidation with some amorphous calcifications ( fig . 1b ) ; hence , the possibilities of fungal infection or granulomatous disease were considered initially . this patient had no fever and did not report associated symptoms of infectious or inflammatory respiratory tract diseases ; therefore , a ct - guided biopsy of the pulmonary lesion was performed because of the concern of atypical pulmonary metastases . microscopically , the specimen showed nearly total necrosis and the presence of atypical cells ; within the mesenchymal element , some osteoid materials and foci of osteonecrosis were noted ( fig . immunohistochemical studies were positive for vimentin , negative for ttf-1 ( thyroid transcription factor-1 ) and cytokeratin . a review of the surgical specimen from the patient 's right parotid gland nine months ago revealed similar findings . the specimen obtained during the lung biopsy showed no carcinomatous component , and did not demonstrate tumor emboli in pulmonary vessels . a radionuclide bone scan did not reveal increased activity at locations other than right neck and lung . retrospective reading of his neck ct nine months ago clearly depicted calcification within the right parotid gland tumor ( fig . the lung is a common site for metastases . large autopsy series of patients with extrathoracic malignancies reveal pulmonary metastases in 20 - 54% of cases ( 6 , 7 ) . typical radiologic findings of pulmonary metastases may include multiple round variable - sized nodules and a diffuse thickening of interstitium , representing hematogenous metastases and lymphangitic carcinomatosis , respectively ( 7 , 8) . in daily practice , however , atypical radiologic features of metastases herein we describe a case of atypical pulmonary metastases from a true malignant mixed tumor of the parotid gland demonstrating calcification and an air - space pattern of the pulmonary metastases . calcification of a pulmonary nodule is usually suggestive of its benign nature , most commonly a granuloma and less commonly a hamartoma . however , calcification or ossification can also occur in metastases from a variety of tumors including osteosarcoma , chondrosarcoma , synovial sarcoma , giant cell tumor of the bone , carcinomas of the colon , ovary , breast , and thyroid ( 7 ) . in our case , the mesenchymal component of the true malignant mixed tumor of the parotid gland was osteosarcoma . as a result , the lung metastases show calcification or ossification ; this observation was confirmed with a ct - guided biopsy . metastases from an extrapulmonary adenocarcinoma may spread into the lung along the intact alveolar walls ( lepidic growth ) in a fashion similar to a bronchioloalveolar carcinoma and exudative pneumonia ( 7 , 8) . this type of metastases may demonstrate an air - space pattern in radiologic studies . in one series , six of 65 patients with pulmonary metastases from an adenocarcinoma of the gastrointestinal tract had this pattern of metastasis ( 8) . in addition , adenocarcinomas from the breast and ovary can also show this pattern of metastasis ( 9 ) . the malignant epithelial component in our case was poorly differentiated carcinoma , and unusual scenario for the development pulmonary metastasis of air - space pattern . ( 10 ) described a variety of atypical locations and presentations of thoracic metastases from osteosarcoma in 16 patients ; pulmonary metastasis of air - space pattern did not occur in their series . in our case , the extensive necrosis revealed by the lung biopsy may be one of speculative mechanisms of air - space pattern . pulmonary infarction due to the presence of a tumor embolism may also demonstrate an air - space pattern ( 7 ) . however , in our case , the limited pieces of specimen obtained at lung biopsy did not demonstrate foci of carcinomatous components and were negative for the presence of a tumor embolism . although we could not explain the definitive mechanism of air - space pattern on the basis of limited histopathologic analysis , the current case demonstrated an extremely rare example of atypical pulmonary metastases from a true malignant mixed tumor of the parotid gland . although most cases of pulmonary metastases can be diagnosed radiologically on the basis of typical findings , atypical radiologic manifestations of pulmonary metastases make confident diagnosis difficult , as in our case . an awareness of the possibility of atypical pulmonary metastases in patients with known extrapulmonary malignancy was crucial to allow an accurate diagnosis . in cases displaying atypical radiologic features of pulmonary metastases , tissue diagnosis at bronchoscopy or percutaneous transthoracic needle aspiration biopsy
a 58-year - old male patient presented with a recurrent true malignant mixed tumor of the parotid gland . 
 patchy pulmonary opacities were identified with a chest radiograph . 
 subsequently , a ct scan of the chest showed pulmonary parenchymal consolidation with amorphous calcifications . this abnormality was confirmed to be the result of a metastatic true malignant mixed tumor by using ct - guided biopsy . 
 the current case demonstrated an extremely rare example of atypical pulmonary metastases from a true malignant mixed tumor of the parotid gland showing an air - space pattern and calcification .