Pulmonary blastoma: A clinicopathologic study of three cases.

Abstract

e19140 Background: Pulmonary blastoma (PB) is a rare biphasic neoplasm representing 0.2-0.5% of pulmonary malignancies. Presentation ranges from asymptomatic to symptoms of advanced pulmonary tumors. Surgery is the preferred treatment with no consensus on the role of other adjuvant therapies. Methods: We report the clinicopathologic features of PB in 3 patients (pts). Retrospective review of medical records of pts diagnosed with PB at Jackson Memorial Hospital, Miami, FL since 2009. Staging performed using the 2009 AJCC system for NSCLC. Cases required pathological diagnosis before inclusion. Variables analyzed were demographics, clinicopathologic presentation, treatments and outcomes. Results: Mean age at diagnosis was 53 years old; 2 were male; Hispanic and Caucasian and 1 African American female. Both males were heavy smokers. At diagnosis, all cases were symptomatic; 1 had hypercalcemia of 12.9 mg/dL and 2 were stage IV with metastatic disease (bone and thyroid). 2/3 where treated with surgical resection and both achieved complete remission (CR); Pt with stage IV and resection relapsed in 28 months, received chemotherapy (3 cycles cisplatin/docetaxel) with progressive disease then radiation (37 Gy) without response and died. The other surgical patient remains in CR. The patient with unresectable disease received chemotherapy (6 cycles carboplatin/docetaxel) attaining partial remission. 2/3 patients remain alive at end of this study. Pathologically, all cases showed biphasic morphology composed of multiple glandular structures with atypical pseudostratified columnar epithelium and cellular stromal component. Immunohistochemical analysis revealed positivity in all cases for thyroid transcription factor (TTF-1), keratin, and epithelial membrane antigen (EMA) in the glandular component. Conclusions: All pts were symptomatic at diagnosis and 2 presented with metastatic disease. All pts had similar morphologically and immunophenotypically. Surgery was the most beneficial intervention in regard to CR and PFS. Chemotherapy has shown mixed responses, thus, larger studies are needed to define the role of chemotherapy in the adjuvant and palliative settings.