Contributed by Simion Chiosea, MD and Anil Parwani, MD, PhD
Published on line in September 2005
A 33-year-old male presented with a 2-week old uncomfortable mass within his left testicle. His serum -hCG was elevated (345.2 mIU/mL). Ultrasound examination demonstrated a heterogeneous, hypoechoic mass. The patient subsequently underwent left radical orchiectomy and epididymectomy. Two weeks after the operation -hCG level was less than 2 mIU/ml. Clinical and radiological staging was negative.
Gross examination showed two lesions. First, a well demarcated lobular mass involving approximately 75% of the testis. It was solid, with hemorrhagic and necrotic areas comprising approximately 15% of the tumor. The tunica albuginea was dull but did not appear to be breached by the tumor.
The second lesion involved the head of the epididymis, which was mostly replaced by a firm, encapsulated yellow 2.0 x 0.9 x 0.8 cm mass and was separate from the testicular mass. Adjacent to the surface of the head of the epididymis was a translucent cyst, 1.2 cm in diameter, filled with clear fluid.
Histological examination of the first lesion demonstrated solid nests of monomorphic large tumor cells compartmentalized by fibrous septa with moderate inflammatory infiltrate. Tumor cells were characterized by abundant clear cytoplasm, prominent nucleoli and well-defined cellular membranes (not shown). The intratubular growth pattern of the neoplasm was highlighted by CD117 (c-kit) immunostain. A diagnosis of classical seminoma was rendered.
Microscopic examination of the second lesion revealed dilated efferent ductules filled with eosinophilic colloid-like luminal fluid (Figure 1, also see "whole slide imaging"). Some areas showed papillary infoldings projecting into cystic spaces lined by cuboidal epithelium with clear cytoplasm (Figures 2 and 3). The transition between these two components was sharp (Figure 3). The intervening stroma was vascular. Mild variation in nuclear size was noted focally, along with 1-2 small nucleoli. The tumor cells were strongly reactive for low molecular weight cytokeratin (CAM5.2, Figure 4).
DIAGNOSIS and DISCUSSION