13 June 2008 – Case of the Week #122
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Case of the Week #122
A 43 year old man presented with a painless testicular mass and normal serum AFP and beta-hCG. Fine needle aspiration cytology was followed by orchiectomy.
The tumor was 2.5 cm, tan brown and soft. The mass was within the testicular parenchyma.
What is your diagnosis?
Leydig cell tumor of the testes
An inhibin stain was diffusely and strongly positive (image).
Leydig cell tumors comprise 1-3% of testicular tumors. Although they arise at any age, most patients are 20-60 years old. They often secrete androgens, estrogens or corticosteriods, and patients may present with gynecomastia or other feminizing symptoms (Hum Path 1977;8:621), or with precocious puberty without spermatocytic maturation.
Grossly, the tumor is usually a solid, well circumscribed nodule 5 cm or less, with a distinct golden-brown homogenous cut surface. Up to 10% have extratesticular extension. Microscopically, there are sheets, nests, ribbons or cords of large, round or polygonal cells with defined cell borders, eosinophilic cytoplasm and round central nuclei. The cytoplasm may contain vacuoles, lipofuscin or Reinke crystals (35%). The tumor cells may display endocrine atypia. Occasionally, cells may have adipose differentiation, which should not be confused with extratesticular extension (AJSP 2002;26:1424). There is no/rare mitotic activity.
Positive immunostains include inhibin, MelanA and keratin, as well as vimentin and steroid hormones. Tumor cells are negative for S100.
The differential diagnosis includes nodular Leydig cell hyperplasia (associated with cryptorchidism, usually 1 cm or less, multifocal, does not destroy surrounding tubules), Large cell calcifying Sertoli cell tumor (usually multifocal, often bilateral, more stroma, calcifications, intratubular growth, no Reinke’s crystals, slightly different immunostaining pattern, Pathol Int 2005;55:366) and testicular tumors of adrenogenital syndrome (bilateral, multifocal, clinical symptoms, laboratory findings, shrink after corticosteroid therapy)
Orchiectomy is usually curative for benign tumors, although testis-sparing surgery has also been advocated for young men (Int J Clin Pract 2003;57:912). In adults, 10% of tumors have malignant behavior, with metastases to lymph nodes, lung and liver. These tumors are usually > 5 cm with necrosis, vascular invasion, nuclear atypia, numerous mitoses including atypical ones, and infiltrative margins.
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