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Testis and epididymis
Germ cell tumors
Spermatocytic seminoma
Reviewer: Rafael Jimenez, M.D. (see Reviewers page)
Revised: 21 April 2013, last major update September 2012
Copyright: (c) 2002-2013, PathologyOutlines.com, Inc.
Definition
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- Germ cell tumor not related to classic seminoma; does not arise from intratubular germ cell neoplasia
- Contains 3 cell types, varying from lymphocyte size to multinucleated giant cells, but mostly composed of intermediate sized cells (Arch Pathol Lab Med 2009;133:1985)
Epidemiology
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- Rare; 1-4% of all seminomas (J Urol 2007;178:125)
- Mean age 55 years, but also occurs in younger patients (Eur Urol 2004;45:495)
- Note: the most common testicular tumor in men age 60+ years is diffuse large B cell lymphoma
Etiology
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- Unlike classic seminoma, does not arise from intratubular germ cell neoplasia - may derive from differentiated spermatogonia
Clinical features
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Prognostic factors
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Case reports
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Treatment
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Gross description
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- Pale gray, mucoid, edematous
- Soft, friable cut surface
- Mean 7 cm
- 10% bilateral
Gross images
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Mucoid tumor
Nodular gray-white tumor
Cystic and mucoid tumor
Micro description
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- Nodules of cells with edema filled spaces causing pseudoalveolar appearance
Three types of cells:
- Small cells (6-8 microns) with narrow rim of eosinophilic cytoplasm resembling lymphocytes
- Medium cells (15-18 microns) with round nuclei, filamentous chromatin and eosinophilic cytoplasm (resemble spermatocytes but diploid)
- Giant cells (50-100 microns) with one or more nuclei
- Increased number of apoptotic cells (Mod Pathol 2007;20:1036)
- May have numerous mitoses
- Usually no stroma, no lymphocytes, no glycogen, no granulomas
- Usually not associated with intratubular germ cell neoplasia or other types of germ cell neoplasia
- 6% of cases are associated with a sarcomatous component, which is usually intermingled with the spermatocytic seminoma cells
- The sarcomatous component is usually undifferentiated or shows muscle differentiation
- Anaplastic variant: focal areas of predominantly medium cells containing prominent nucleoli; no clinical evidence of aggressive behavior (Hum Pathol 1996;27:650)
Micro images
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Diffuse growth pattern
Large nodules have focal
pseudoglandular pattern
Various images
Numerous apoptotic cells
No lymphocytes or granulomas
Edema has caused a cystic pattern
Edema fluid-filled spaces
Figures 1 and 2
Figure 3
Figure 4
Figure 5
Fig 1&2: Polymorphic population of mainly small cells with dark nuclei, intermediate cells with pale nuclei and occasional multinucleated giant cells
Fig 3: Extensive intercellular edema causes a pattern of small nests, trabeculae, clusters and single cells
Fig 4: Intratubular growth: note the filamentous ("spireme") chromatin in some of the larger cells
Fig 5: Intratubular growth: one tubule shows normal spermatogenesis
Unusual features:
Tumor nests and cords mixed with lymphocytes
Prominent granulomatous
reaction and
lymphoid infiltrate
Intratubular component surrounded by sarcomatous growth with features of embryonal rhabdomyosarcoma
Sarcomatous component
MAGE-A4+
(also present in spermatogonia)
Cytology description
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- Clean background; three populations of cells (small, medium, and large), with a preponderance of medium-sized cells showing visible nucleoli; low mitotic rate; no lymphocytes (Diagn Cytopathol 1999;20:233)
Cytology images
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Numerous small lymphocyte-like cells,
intermediate cells with filamentous
chromatin, and rare giant cells
Positive stains
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Negative stains
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- Keratin (may have focal staining), EMA, PLAP, OCT3/4 (Am J Surg Pathol 2004;28:935), hCG, AFP, CEA, EMA, CD30
- Also HPL, NSE, Angiotensin 1 converting enzyme (ACE)
Electron microscopy description
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- Cytoplasmic bridges between tumor cells resembles those between spermatocytes
- Thickening of plasma membrane, microtubules between cells
- Minimal or no glycogen
Electron microscopy images
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Figure 1
Figure 2
Fig 1: Intercellular bridge joins two tumor cells, as in normal spermatocytes
Fig 2: A nest of spermatocytic seminoma is surrounded by a well defined basement membrane; there are numerous mitochondria, a Golgi apparatus and round nuclei with dispersed chromatin
Molecular / cytogenetics description
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Differential diagnosis
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- Classic seminoma: fibrous stroma with prominent lymphocytes, often granulomatous reaction, seminoma cells have squared off nuclei; also intratubular germ cell neoplasia; lacks 3 cell types; PLAP+, PAS+ (glycogen), OCT3/4+
- Embryonal carcinoma: has markedly atypical cells, intratubular germ cell neoplasia; lacks 3 distinct cell types, AE1-AE3+, OCT3/4+, CD30+
End of Testis and epididymis > Germ cell tumors > Spermatocytic seminoma
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