Pulmonary Lymphangitic Sarcomatosis of Primitive Neuroectodermal/Ewing's Sarcoma

Abstract

INTRODUCTION: Pulmonary lymphangitic carcinomatosis (PLC) accounts for 6% of metastasis to the lung and is associated with a dismal prognosis. The most common sites of origin are the breast, lung, stomach, pancreas, and cervix. Lymphangitic spread of sarcomas, or “lymphangitic sarcomatosis ” (PLS) is extremely rare, as sarcomas tend to disseminate hematogenously. Only a few cases of PLS have been reported. Here we describe the clinical, radiologic, and histologic features of pulmonary lymphangitic dissemination of a primitive neuroectodermal/Ewing's sarcoma (PNET/ES). To our knowledge, this is the first report of the PLS due to PNET/ES. CASE PRESENTATION: A 67 year old man presented with a 2 week history of night sweats, asthenia, subjective fevers and a nonproductive cough. He denied dyspnea, hemoptysis, and weight loss. The patient received a course of amoxicillin/clavulanate without improvement. The patient's past medical history was significant for systemic amyloidosis remaining in remission following an autologous bone marrow transplant 10 years ago. Two years prior to presentation, he developed a poorly differentiated PNET/ES of the S2 sacral nerve root which was resected and treated with cyclophosphamide, doxorubicin and vincristine, alternating with ifosphamide and etoposide. Local pelvic recurrence was identified 5 months prior to presentation, for which he underwent external beam radiation therapy. Examination revealed new bibasilar rales, and laboratory studies were remarkable for an elevated lactic dehydrogenase level (555 U/L). Computed tomography (CT) of the chest revealed multiple diffuse micronodules and tiny, new bilateral pleural effusions. The subpleural distribution of the nodularity as well as the irregular thickening of the lymphatics studded with micronodules were consistent with possible lymphangitic metastases. Because of a former smoking history, the initial concerns were for PLC. A bronchoscopy was performed. Although the bronchoalveolar lavage was unrevealing, transbronchial lung biopsies confirmed metastases of PNET/ES. Cytokeratin and TTF-1 stains were negative and vimentin, S-100, and CD-99 stains were positive, consistent with metastatic Ewing's sarcoma. He subsequently received cyclophhosphamide and topotecan with significant clinical and radiological improvement. DISCUSSION: PNET/ES are rare, aggressive neoplasms that belong to the ES family of tumors (EFT). The most important prognostic factor for prognosis is the presence of clinical metastasis. Lung metastasis via hematogenous tumor embolization represents the first site of distant spread in 70-80% of cases, and are the leading cause of death for patients with ES. The most common presentation of sarcomatous metastasis to the lung is that of multiple well-circumscribed randomly-distributed pulmonary nodules. In contrast to carcinomas, only 2-5% of sarcomas metastasize to lymph nodes, and these have not been shown to present with lymphangitic spread. Most cases of PLC arise from adenocarcinomas. The CT can be highly suggestive with the characteristic irregular thickening of the interlobular septa and bronchovascular bundles, polygonal arcade formation and lack of distortion of the lung parenchyma despite extensive involvement. Pleural effusions and lymphadenopathy are also common. Because of the rarity of PLS, its behavior is difficult to characterize and diagnosis may be delayed. The limited reports of PLS have been on one primary pulmonary angiosarcoma, intravascular bronchoalveolar tumors (epitheliod hemangioendotheliomas), one limb cutaneous hemangiosarcoma, osteosarcomas, mesotheliomas with sarcomatoid features, and Kaposi's sarcomas. CONCLUSIONS: This case represents the first description of lymphangitic spread of a PNET/ES and underscores the fact that in patients with this diagnosis and a compatible CT of the chest, PLS should be considered in the differential diagnosis and transbronchial lung biopsy can be diagnostic.