General Concepts, Sex Cord/Gonadal Stromal Tumors



General Concepts, Sex Cord/Gonadal Stromal Tumors


Steven S. Shen, MD, PhD

Jae Y. Ro, MD, PhD








Leydig cell tumor with solid and nested growth patterns is shown. The tumor cells are uniform, round, and have prominent nucleoli image and abundant eosinophilic/granular cytoplasm.






Sertoli cell tumor with tubular image pattern is shown. The tumor cells have ovoid to round nuclei with occasional prominent nucleoli image and pale eosinophilic cytoplasm.


TERMINOLOGY


Definitions



  • Neoplasms that have features of Leydig (interstitial) cells, Sertoli cells, granulosa cells, or rarely, theca cells


  • Sex cord stromal tumor (SCST) may be of mixed classifiable sex cord stromal cells (mixed SCST) or unclassifiable sex cord stromal cell (unclassified SCST)


  • Cases of mixed germ cell and SCST reported (gonadoblastoma and unclassified type)


EPIDEMIOLOGY


Incidence



  • 4-6% of adult testicular neoplasms


  • 30% of testicular tumors in infants and children


  • Unlike germ cell tumors, there is no racial difference in frequency


ETIOLOGY/PATHOGENESIS


Histogenesis



  • Poorly understood in general


  • May relate to disruption of hypothalamic-pituitarytesticular axis and hormonal disturbance


  • No definitive association with cryptorchidism


  • Specific types of sex cord stromal tumor may be associated with genetic syndromes; e.g., large cell calcifying Sertoli cell tumor in Peutz-Jeghers syndrome and testicular feminization syndrome for Sertoli cell tumors


  • Although testicular granulosa cell or theca cell tumors have been reported, no granulosa or theca cells are present in normal testis


CLINICAL IMPLICATIONS


Presentation



  • Painless mass (rarely painful)


  • Asymptomatic or hormone-related symptoms


  • Infants with Leydig cell tumor usually present with isosexual pseudoprecocity


  • Some types may cause gynecomastia or impotence


Treatment



  • Surgical approaches



    • Orchiectomy is curative; staging work-up required


    • Testis sparing resection possible


Prognosis



  • Approximately 10% of adult-type SCSTs are malignant and may metastasize


  • Metastasis is the only reliable criterion for malignancy; histologic factors alone may not predict malignancy


  • Features that may be associated with disease progression include



    • Nuclear pleomorphism, frequent and abnormal mitosis (> 4/10 high-power fields), necrosis


    • Infiltrative growth, large size (> 5 cm), extension to paratesticular tissue, and vascular invasion


  • Tumors occurring in infants and children are almost always benign with rare exceptions


Clinical Presentation



  • Painless testicular swelling or mass


  • Symptomatology of hormonal disturbance or genetic syndrome


MACROSCOPIC FINDINGS


General Features



  • Size



    • Range from microscopic to several cm (malignant forms usually larger, > 5 cm)



Specimen Handling



  • Total Resection



    • Procure cord margin before cutting into testis


    • Small tumors may be entirely embedded


    • Submit at least 1 section/cm tumor



      • Sections to include: Tumor with adjacent parenchyma


      • Sections to include: Rete testis, epididymis, and spermatic cord


      • At least 2 sections of grossly normal parenchyma


  • Subtotal Resection



    • Ink resection margin 1st


    • Take perpendicular sections of tumor with margin


    • Submit entire tumor, if appropriate


    • Sections to include: Normal parenchyma


MICROSCOPIC FINDINGS


Normal Histology



  • Interstitial (Leydig) cells



    • Present in interstitium as single cells or in clusters


    • They may be also present in tunica albuginea, rete testis, epididymis, and spermatic cord (ectopic Leydig cells)


    • Leydig cells have uniform, round nuclei, prominent nucleoli, and abundant eosinophilic cytoplasm


    • Intracytoplasmic lipofuscin pigment may be seen, particularly in older men


    • Reinke crystalloids (better demonstrated with trichrome stains)


    • Immunoreactive with vimentin, inhibin, and calretinin, but not cytokeratin (may be focally and weakly positive)


  • Seminiferous tubules and Sertoli cells



    • Sertoli cells are located within seminiferous tubules and comprise approximately 10-15% of cells within tubules (germ cell:Sertoli cell ratio is ~ 13:1)


    • Located 1 or 2 cells away from basement membrane of tubules


    • Pyramidal shaped-cells with round to ovoid nuclei, finely granular chromatin, often prominent nucleoli


    • Cytoplasm is eosinophilic and granular with fine vacuoles


    • Immunoreactive with vimentin, Cam5.2, CK19, inhibin, and calretinin


  • Granulosa cells



    • Probably represent precursor Sertoli cells in fetal seminiferous tubules


    • These cells are cuboidal or columnar in shape and rest on tubular basement membrane


    • Not found in normal adult testis


  • Undifferentiated sex cord stromal cells



    • Present early in fetal gonadal development


    • Primitive cells with potential for elaboration of steroid hormones


    • Not found in normal adult testis


General Features



  • World Health Organization (WHO) Histologic Classification of sex cord stromal tumors of testis



    • Leydig cell tumor (LCT)


    • Malignant LCT


    • Sertoli cell tumor (SCT)



      • SCT, lipid-rich variant


      • Sclerosing SCT


      • Large cell calcifying SCT


    • Malignant SCT


    • Granulosa cell tumor (GCT)



      • Adult type GCT


      • Juvenile GCT


    • Tumor of thecoma/fibroma group



      • Thecoma


      • Fibroma


    • Sex cord/gonadal stromal tumor (SCST), mixed/unclassified type



      • Incompletely differentiated SCST


      • SCSTs, mixed forms


      • Malignant SCSTs


    • Tumors containing both germ cell and sex cord/gonadal stromal elements



      • Gonadoblastoma


      • Germ cell sex cord/gonadal stromal tumors, unclassified


Cytologic Features



  • Depends on tumor types


Predominant Pattern

Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on General Concepts, Sex Cord/Gonadal Stromal Tumors
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