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].