Ann Thorac Surg 2009;87:1925-1926. doi:10.1016/j.athoracsur.2008.10.062
© 2009 The Society of Thoracic Surgeons
Case Reports
Primary Yolk Sac Tumor of the Lung
Abdel Rahman M. Abdel Rahman, MDa,
Emad N. Ebied, MDb,
Mohamed A. Nouh, MDc,
Anthony A. Gal, MDd,
Kamal A. Mansour, MDe,*
a Department of Surgery, National Cancer Institute, Cairo, Egypt
b Department of Pediatric Oncology, National Cancer Institute, Cairo, Egypt
c Department of Pathology, National Cancer Institute, Cairo, Egypt
d Department of Pathology, General Thoracic Section, Emory University, Atlanta, Georgia
e Department of Surgery, General Thoracic Section, Emory University, Atlanta, Georgia
Accepted for publication October 21, 2008.
* Address correspondence to Dr Mansour, Cardiothoracic Surgery, The Emory Clinic, 1365 Clifton Road, NE, Atlanta, Georgia 30322 (Email: kamal.mansour{at}emoryhealthcare.org).
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Abstract
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Yolk-sac tumor mimics the yolk sac of the embryo, and the presence of alpha fetoprotein in the tumor cells is highly characteristic. We present an 18-year-old boy with primary pulmonary yolk-sac tumor diagnosed postoperatively. A computed tomographic scan revealed a huge intrathoracic soft tissue mass 20 x 25 cm occupying most of the left hemithorax. Two trials of computed tomographic-guided needle biopsy were nonconclusive. A left upper lobectomy was performed with a complete tumor resection. Postoperatively, the patient's alpha fetoprotein (AFP) was 10,512 IU/mL with gradual decline under chemotherapy. The patient is alive 10 months after surgery and is disease free.
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Introduction
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Primary malignant extragonadal germ cell tumors of the lung are quite uncommon and pure pulmonary yolk sac tumor is so rare that it is hardly included in the differential diagnosis of pulmonary masses. There is general agreement that these tumors occur in the younger age group, grow rapidly, are large and necrotic, and are associated with elevated levels of alpha fetoprotein (AFP). The first case of a pure primary pulmonary yolk-sac tumor was published in 1993 by Inoue and colleagues [1], and Pelosi and co-workers [2] published the second case in 2006.
We present a case of pure primary pulmonary yolk-sac tumor diagnosed postoperatively in an 18-year-old boy. The symptoms started 1 year earlier with intermittent left anterior chest wall "stitching" pain relieved by mild analgesics.
Eight months later the pain became more severe, radiating to the left shoulder and left subscapular area. The patient complained of progressive dyspnea, which was worse when lying on the right side. This was accompanied by dry cough, but no hemoptysis.
On examination, there was restricted left-sided chest movement and left-sided dullness on percussion associated with markedly diminished air entry.
A chest roentgenogram showed opacification of the left hemithorax with contralateral mediastinal shift. A computed tomographic scan revealed a huge intrathoracic soft tissue mass (20 x 25 cm) occupying most of the left hemithorax with no plane between it and the chest wall with central breakdown (Fig 1). No lung parenchyma was appreciated. There was no associated pleural effusion, pulmonary nodules, or mediastinal lymph node enlargement. Two trials of computed tomographic-guided needle biopsy were done; the first revealed necrotic tumor cells and the second showed small round tumor cells. During the last two weeks before exploration, the general condition of the patient started to deteriorate with increasing pain and dyspnea.
Through a left posterolateral thoracotomy incision, the tumor was found to be directly under the chest wall and was adherent in parts to the parietal pleura and pericardium. Using an extrapleural dissection, the mass was separated from the mediastinum, taking care to preserve the phrenic bundle. There was no chest wall or mediastinal invasion. Dense adhesions to the pericardium were encountered that required partial pericardiectomy. The tumor was found arising from the left upper lobe with no mediastinal involvement and was compressing the lower lobe bronchus without crossing the fissure. Intraoperative diagnosis was primary lung sarcoma. A left upper lobectomy and mediastinal nodal sampling was done. The patient had an uneventful postoperative course and was discharged on the postoperative day 7.
Pathologic examination revealed a primary intrapulmonary pure yolk-sac tumor arising from the left upper lobe. The tumor seemed to surround the left upper lobe bronchus without invading it. All dissected lymph nodes were free of metastases (0 of 19). There was no evidence of teratomatous or choriocarcinoma elements. Microscopically, sections showed a malignant microcystic neoplasm within the lung with necrosis and hemorrhage. The tumor cells, surrounded by a myxoid stroma, had vesicular nuclei and prominent nucleoli. Occasional Schiller-Duvall bodies were noted. Features of other germ cell components or pulmonary blastoma were not identified. By immunohistochemistry, the tumor cells were strongly immunoreactive for AFP (Fig 2). The diagnosis was supported by tissue markers and serum AFP that was ordered on postoperative day 5 and was 10,512 IU/mL (mean level, 7.4 IU/mL). Testicular AFP ultrasound and computed tomographic scan of the abdomen and pelvis were done to exclude primary gonadal or retroperitoneal yolk sac.
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Fig 2. Pulmonary yolk sac tumor. There is a prominent microcystic pattern composed of anastomosing tumor cells with prominent cytoplasmic vacuolation. (Hematoxylin & eosin; x100.)
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Two weeks after surgery, the AFP level dropped to 3,870 IU/mL. Four weeks later, the patient started adjuvant bleomycin, etoposide, and cisplatinum (PEB) regimen, consisting of cisplatin, 100 mg/m2 on day 1; etoposide, 100 mg/m2 days 1–5; and bleomycin, 15 mg/m2 on day 2 and day 9. The AFP dropped to 683 IU/mL after the first cycle. He received four cycles of the same regimen and his AFP was 44.2. The patient received two more cycles without bleomycin and his serum AFP dropped to 16 IU/mL, although his renal scan and estimated glomerulofiltration rate were normal. Four more cycles of carboplatin (560 mg/m2) on day 1 and etoposide (100 mg/m2) on days 1 to 5 were given with more decline in the serum level of AFP to normal value after the tenth cycle. The last cycle of chemotherapy was in December 2007. The last follow-up was in July 2008 with normal computed tomographic chest, abdomen, and pelvis scans and normal AFP serum level.
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Comment
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The origin of extragonadal germ cell tumor is not well understood, mediastinal germ cell tumor may arise from nests of primordial germ cells that remain in the region of anterior mediastinum, at the time of migration along the gonadal ridge during embryogenesis [3, 4]. Because of the rarity of pulmonary germ cell tumors, the exact origin of such pulmonary tumors is not known and may be the same as that of mediastinal origin.
The treatment of choice for yolk-sac tumor is neoadjuvant chemotherapy for optimal cytoreduction to be followed by resection of the residual tumor. If the final pathology shows viable tumor cells, adjuvant chemotherapy is added. Due to the extreme rarity of the tumor and difficulty in making the diagnosis preoperatively, surgical resection is usually the primary diagnostic and therapeutic modality and should be followed by chemotherapy. If the diagnosis is made preoperatively, serum level of AFP should be done as a baseline test or done immediately once postoperative diagnosis is made, as it is considered a good therapeutic and prognostic marker.
Patients with mediastinal and pulmonary yolk-sac tumors carry a poor prognosis and have a lower likelihood of achieving a complete response to combined modality therapy [5]. The rate of decrease of serum AFP after surgery may have a prognostic value. The half-life clearance of serum AFP has shown to be less than 5 to 7 days [6]. Therefore, a prolonged post-therapy decline in serum AFP may serve as an unfavorable prognostic factor as with our patient who had a slow decline in serum AFP.
Computed tomographic-guided true-cut needle biopsy should be done for those patients with fine-needle aspiration biopsy revealing small round cell tumor. However, if preoperative diagnosis can not be reached after repeated negative or nonconclusive biopsies, exploratory surgery for both diagnosis and treatment should be the rule in this subset of patients. The diagnosis of a primary malignant, extragonadal germ cell tumor is to be established if the criteria set by Einhorn [7] are fulfilled. These include absence of a detectable or subsequent appearance of a gonadal tumor and absence of nodal metastases in the para-aortic and iliac regions. With these stringent criteria, the lung emerges as an extremely uncommon site for such tumors.
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References
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- Inoue H, Iwasaki M, Ogawa J, et al. Pure yolk-sac tumor of the lung Thorac Cardiovasc Surg 1993;41:249-251.[Medline]
- Pelosi G, Petrella F, Sandri MT, Spaggiari L, Galetta D, Viale G. A primary pure yolk sac tumor of the lung exhibiting CDX-2 immunoreactivity and increased serum levels of alkaline phosphatase intestinal isoenzyme Int J Surg Pathol 2006;14:247-251.[Abstract/Free Full Text]
- Lewis BD, Hurt RD, Payne WS, Farrow GM, Knapp RH, Muhm GR. Benign teratomas of the mediastinum J Thoracic Cardiovascular Surg 1983;86:727-731.[Abstract]
- Fechner LP. Germ cell tumor of the mediastinum Semin Diagn Path 1990;7:266-284.
- Toner GC, Geller NL, Lin SY, Bosl GJ. Extragonadal and poor risk nonseminomatous germ cell tumors: survival and prognostic features Cancer 1991;67:2049-2057.[Medline]
- Toner GC, Geller NL, Tan C, Nisselbaum J, Bosl GJ. Serum tumor marker half-life during chemotherapy allows early prediction of complete response and survival in nonseminomatousgerm cell tumors Cancer Res 1990;50:5904-5910.[Abstract/Free Full Text]
- Einhorn LH. Extragonadal germ cell tumorsIn: Einhorn LH, editor. Testicular tumors. New York: Masson Publishing; 1980. pp. 185-204.
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Abstract
Introduction
