Low-Grade Osteosarcoma of the Lung Diagnosed at the Time of Recurrence

Characteristics and prognosis of primary pulmonary osteosarcoma: a pooled analysis

BACKGROUND

Primary pulmonary osteosarcoma (PPOS) is an uncommon malignancy originating from the lung with low incidence, and its clinical characteristics and prognosis have not been systematically reported. Therefore, we aimed to recognize the prognostic factors and constructed a survival prediction model for PPOS.

METHODS

We collected the data from the Surveillance, Epidemiology, and End Results database and systematic review of previous studies. Demographical and clinical characteristics, radiographic manifestations, treatment modalities, and prognosis were analyzed. A prediction model via nomogram was constructed and then evaluated by the concordance index (C-index) and the receiver operating characteristic (ROC) curve.

RESULTS

A total of 49 cases were included for analysis with a median age of 67 years old (range 33-94 years), of which 32 (65.3%) were male. The median size was 6 cm (range 1.8-25 cm), and the median overall survival (OS) was eight months (interquartile range 4.5-12 months) with a 1-year OS rate of 30.8%. Tumor size over 7 cm (hazard ratio [HR] = 2.98; P = 0.018) and those without microscopic findings of osteoid found in the tumors (HR = 2.11; P = 0.048) were referred to a poor OS, while surgery was associated with an improved OS (HR = 0.20; P < 0.001). The C-index of the nomogram prediction model was 0.771, and the area under curve, sensitivity and specificity of the ROC curve were 0.818, 0.848 and 0.800, respectively.

CONCLUSIONS

Patients with PPOS had a poor prognosis, and tumor size was mostly prognostic. Surgery seemed to be an effective treatment, and the prediction model with a nomogram in our study could effectively predict the prognosis of patients with PPOS.

Malignant pleural mesothelioma with heterologous elements

AIMS

Malignant pleural mesothelioma with heterologous elements (such as osseous, cartilaginous or rhabdomyoblastic differentiation) is very rare. We tried to differentiate such mesothelioma cases from extraskeletal pleural osteosarcoma, which is very challenging.

METHODS

We compared 10 malignant pleural mesotheliomas (three biphasic and seven sarcomatoid types) with two pleural osteosarcomas using clinicopathological and immunohistochemical methods, and also fluorescence in situ hybridisation (FISH) to examine for homozygous deletion of p16.

RESULTS

The median age was 72 years for mesotheliomas, and 69 years for osteosarcoma. For mesothelioma, eight cases were male and two were female. Growth was diffuse in all mesothelioma cases except case 10, where it was localised, as it was for the two osteosarcomas. Among mesothelioma cases, 80% displayed osteosarcomatous and 60% chondromatous elements, while 10% exhibited rhabdomyoblastic ones. Immunohistochemical labelling for calretinin and AE1/AE3 was present in 8/10 and 7/10 mesotheliomas, respectively, but in only one osteosarcoma. Loss of methylthioadenosine phosphorylase was seen in 5/7 mesotheliomas. FISH analysis revealed homozygous deletion of p16 in 5/8 mesothelioma and 2/2 osteosarcoma. Median survival was 6.5 months after biopsy or surgical operation in mesothelioma, and 12 months after operation in osteosarcoma.

CONCLUSIONS

Although median survival was longer for osteosarcoma than for malignant mesothelioma, we could not differentiate mesothelioma from pleural osteosarcoma on the combined basis of clinicopathological and immunohistochemical data, and FISH analysis. However, diffuse growth was more frequent in mesothelioma than in osteosarcoma.