Cure of Oligometastatic Classic Biphasic Pulmonary Blastoma Using Aggressive Tri-modality Treatment: Case Series and Review of the Literature

Abstract

Pulmonary blastoma is a rare lung cancer classified into three subtypes: classic biphasic pulmonary blastoma (CBPB), well-differentiated fetal adenocarcinoma (WDFA), and pleuropulmonary blastoma (PPB) of childhood. Compared to the other subtypes, CPPB is an aggressive tumor with an overall five-year survival of 16% across all stages. We present two cases of biopsy-proven metastatic CBPB, who have been disease-free for over 10 years since treatment completion. Both patients were treated with surgery to the primary tumor followed by an adjuvant cisplatin-based chemotherapy for four cycles and thoracic radiation. One patient relapsed shortly after the completion of thoracic radiation with brain metastases and underwent craniotomy, gamma knife radiosurgery (GKRS), and whole brain radiation therapy. The other patient presented with synchronous pelvic metastases and underwent metastasectomy after the completion of chemotherapy but before the initiation of thoracic radiation. We review the literature regarding surgical, chemotherapeutic, and radiation treatment for patients with metastatic pulmonary blastoma. Based on our experience and review of the existing case reports, aggressive tri-modality treatment including surgery, chemotherapy with a cisplatin backbone, and a definitive treatment of oligometastatic lesions amenable to local therapy including resection or radiosurgery is reasonable to consider for medically fit patients with CBPB.

Keywords: chemotherapy; lung cancer; oligometastatic; pulmonary blastoma; radiation therapy.

Figure 1. Case 1: chest imaging

Computed tomography of the chest at presentation showing a 7 x 5-cm left upper lobe mass.

Figure 2. Case 1: lung biopsy

Biopsy from the lung mass demonstrated typical features of classic biphasic pulmonary blastoma including mixed epithelial and mesenchymal differentiation with the epithelial component forming glands composed of columnar cells with a clear cytoplasm, while the mesenchymal component showed solid sheets of blastema-like cells

Figure 3. Case 1: brain metastasis

(A) Brain magnetic resonance imaging at the time of brain metastasis with right 4 x 3.4 x 3.7-cm temporo-occipital cavitary lesion, left parieto-occipital 1.0 x 1.1 x 1.0-cm lesion, vasogenic edema, and right to left midline shift. (B) Biopsy from the brain metastasis consistent with classic biphasic pulmonary blastoma.

Figure 4. Case 2: baseline imaging

(A) Computed tomography of the chest with a 7.7-cm left lower lobe mass. (B) Staging positron emission tomography/computed tomography scan showed a mildly increased uptake in the left adnexal area.

Figure 5. Case 2: imaging of the pelvis

Magnetic resonance imaging of the pelvis was obtained six weeks after her initial positron emission tomography/computed tomography to evaluate the areas of hypermetabolic activity. This showed metastases to bilateral ovaries. The anterior mass was 9.2 x 7.9 x 9.1 cm and the posterior mass was 6.3 x 5.6 x 5.6 cm.