Testicular Mass in an Elderly Man

Deloar Hossain, M.D.

Specimen Type:

Testis

History:

A 75-year-old man presented with right testicular mass underwent radical orchiectomy. Cut sections show a circumscribed mass, measuring 3.0 x 2.0 x 2.0 cm located entirely within the testis. The tunica albugina is intact. The epididymis and spermatic cord are grossly unremarkable. Representative sections are submitted.

Pathologic Features:

Sections from the tumor reveal a well-circumscribed tumor with a fibrous capsule (Figure 1). The growth patterns are diffuse (mainly, cystic, trabecular, tubular (Fig 1, 2, 3, 4, 5, 6, 7). The tumor cells contain scant to moderate amount of cytoplasm and pale, angular, or oval grooved nuclei (Fig 8); nucleoli are conspicuous and mitosis is identified infrequently (Fig 9). Multifocal necrosis and calcification are present (Fig 10, 11). There is prominent collagen production in some areas (Fig 2, 3). Tumor cells are positive for inhibin, CD99, and actin (Fig 12, 13, 14).

Differential Diagnosis:

  • Sertoli-cell tumor (Fig 15)
  • Sex cord-stromal tumor, unclassified (Fig 11)
  • Granulosa cell tumor, adult type

Sertoli-cell tumor: This is a tumor occurring mostly in adult patients, rarely in children. Grossly, tumors are typically well-circumscribed solid masses. Foci of hemorrhage are present, but necrosis is rare. Microscopically, tumors of NOS type show conspicuous tubular differentiation at least focally, and solid pattern are frequently seen; cords can be prominent in some cases. The tumor cells usually have moderate eosinophilic cytoplasm, but it may be pale due to lipid accumulation. The cells have bland cytologic features and little mitotic activity, and occasionally exhibit overt pleomorphism and conspicuous mitotic figures. In a study of 60 tumors, 12% were clinically malignant. The pathologic features that correlate with a clinically malignant course are as follows: a tumor diameter of 5cm or greater, necrosis, moderate to severe nuclear atypia, vascular invasion, and a mitotic rate over 5 mitotic figures per 10 high-power field.

Sex cord-stromal tumor, unclassified: The tumors in this category frequently lack specific differentiation or contain patterns and cells resembling to varying degrees both testicular and ovarian elements. Clinically, 10% of patients present with gynecomastica. Microscopically, a spectrum of patterns is seen, ranging from predominantly epithelial to predominantly stromal. The better differentiated tumors typically contain solid to hollow tubules or cords composed of cells resembling Sertoli cells, and islands of cells resembling granulosa cells. The less differentiated tumors exhibit varying degrees of nuclear pleomorphism and mitotic activity; diffuse and sarcomatoid patterns are frequent and it may be difficult or impossible to distinguish the epithelial and stromal components on routine staining. Spindle cell predominant cases are often reactive for S-100 and actin, similar to granulosa cell tumors.

Granulosa cell tumor, adult type: This is a distinct and rarest group of the sex cord-stromal tumors. The tumor typically occurs in adults with an average of 42 years. Grossly, the tumor is lobulated, brownish-yellow, and solid; cysts are sometime present. Microscopically, the tumor usually displays either microfollicular, with Call-Exner bodies, or diffuse patterns, but other patterns such as gyriform, insular, or macrofollicualr, may be observed. The cytoplasm is typically scanty, and the nuclei are pale with variably prominent grooves.

Diagnosis:

Granulosa cell tumor, adult type

Key Fearures:

  • Grossly: partially or completely encapsulated; firm, lobulated, brownish-yellow
  • Microscopically:
    1. Admixture of a wide variety of patterns: predominant pattern: microfollicular or diffuse;
      Other patterns: gyriform, macrofollicular, insular, trabecular, solid, and pseudosarcomatous
    2. Microfollicular pattern with Call-Exner bodies is characteristic
    3. Tumor cells display scant cytoplasm and pale nuclei with characteristic grooves
    4. Fibrous or thecomatous stroma may be present
  • Immunohistochemically:
    1. Generally positive for vimentin and inhibin;
    2. Variably positive for actin;
    3. Negative for AE1/AE3 and EMA

Comment: This represents an unusual example of adult granulosa cell tumor in that it occurs in an elderly patient and exhibits tubular structures. The major differential diagnosis is sex cord-stromal tumor, unclassified, in which a predominant pattern of testicular or ovarian differentiation is not clearly recognizable, which is not true of the findings in the current case. Diagnosis is based on an admixture of patterns including characteristic microfollicular with Call-Exner bodies, and identification of classic nuclear grooves. If the architectural features are typical of adult granulosa cell tumor, a paucity of nuclear grooves is still consistent with the diagnosis. Granulosa cell tumor in the testis is very rare with about 20 reported cases in the English literature (reference 1). Clinically, this group of tumors usually represents a slow-growing tumor that can potentially cause distant metastasis, which might take place several years after initial presentation. This characteristic clearly warrants long-term follow-up. A size greater than 7 cm, vascular/lymphatic invasion, and hemorrhage or necrosis, are features of malignant tumors (reference 2).

References:

  1. Al-Bozom IA, El-Faqih SR, Hassan SH, et al. Granulosa cell tumor of the adult type: a case report and review of the literature of a very rare testicular tumor. Arch Pathol Lab Med. 2000 Oct;124(10):1525-8.
  2. Jimenez-Quintero LP, Ro JY, Zavala-Pompa A, Amin MB, Tetu B, OrdoƱez NG, Ayala AG. Granulosa cell tumor of the adult testis: a clinicopathologic study of seven cases and a review of the literature. Hum Pathol. 1993 Oct;24(10):1120-5.