Discussion
Testicular tumors can be classified into germ cell tumors, sex cord stromal tumors and mixed germ cell and sex cord stromal tumors. The germ cell can further be classified into tumors derived from germ cell neoplasia in situ (GCNIS) or unrelated to germ cell neoplasia in situ. The former category can be further subdivided into seminomas and non-seminomatous germ cell tumors. Primary yolk sac tumor of the post pubertal type falls into the latter category [6]. Primary yolk sac tumors in the post pubertal age group are very rare [3]. Here we presented a case of a 40-year-old male diagnosed with a primary yolk sac tumor which had spread to involve retroperitoneum and metastasized to lungs on diagnosis. The patient also had a PE and DVT at the time of initial diagnosis.
Microscopic examination of yolk sac tumors consists of primitive cells with many histological types including microcystic, papillary, solid, festoon, poly-vesicular-vitelline, glandular, intestinal, endometroid, parietal, tubular or hepatoid. Schiller Duval bodies are a pathognomonic for yolk sac tumors and it appears like a glomerulus like structure with a fibrovascular core. There is no histopathological difference in the prepubertal and post pubertal yolk sac tumors, but they behave different clinically. The post pubertal yolk sac tumors are much more aggressive than their pre pubertal counterparts. The GCNIS tumors have a common finding of amplification of the 12p chromosome which our patient was also positive for [2].
There has been some report of similar cases in the literature. Medica [7] in 2001 reported a case of adult yolk sac tumor in a 44-year-old male whose AFP was 1733 ng/ml. His disease was localized, and he was treated with surgical resection of the testicular mass with lymph node dissection which was negative for metastatic disease. Behera et al. l [4] reported a similar case to ours in a 37-year-old male who was successfully treated with inguinal orchidectomy and BEP combination chemotherapy. Their patient also had a lung nodule on presentation and after 2 months of completion of chemotherapy, the lung nodule had regressed. Their patient was still doing well with a normal AFP at 4 years follow up at the time of publication. Murcia et al. [2] reported a case of primary yolk sac tumor as well, but their patient was younger (20-year-old) and had metastasis to the liver, retroperitoneum, and lung. Unfortunately, their patient had a precipitous hospital stay and passed away within 3 months of diagnosis.
The present-day treatment for yolk sac tumors is surgery and chemotherapy followed by active surveillance with serial examinations and laboratory follow up. Serum AFP seems to be an important biomarker of disease activity in these cases. The serial measurement of AFP is beneficial in monitoring the clinical course and response to treatment [8].