Sex Cord Stromal Tumor, Mixed/Unclassified



Sex Cord Stromal Tumor, Mixed/Unclassified


Steven S. Shen, MD, PhD

Jae Y. Ro, MD, PhD










Gross photograph shows a well-circumscribed unclassified SCST. It has heterogeneous, soft, tan nodular areas with dense white fibrotic septae. SCSTs frequently do not replace the entire testis.






Unclassified SCST is shown with cellular proliferation of ovoid or elongated cells with scant, pale cytoplasm. No obvious differentiation is present. Vague rosette formation image is seen.


TERMINOLOGY


Abbreviations



  • Sex cord stromal tumor (SCST), Leydig cell tumor (LCT), Sertoli cell tumor (SCT), granulosa cell tumor (GCT)


Definitions



  • Group of SCSTs with mixture of recognizable cell types or composed of incomplete or undifferentiated sex cord stromal cells


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Extremely rare (< 1% of testicular neoplasms)


  • Age



    • All ages


    • More commonly seen in children (30% < 1 year old)


Presentation



  • Painless testicular enlargement


  • 15% associated with gynecomastia


Treatment



  • Surgical approaches



    • Surgical resection is usually curative


    • Testis sparing partial orchiectomy may be possible


    • Radical orchiectomy with retroperitoneal lymph node dissection may be required for patients with clinical evidence of metastasis or high-risk pathologic features


Prognosis



  • Almost always benign in prepubertal children


  • May be malignant in adults (20%)


MACROSCOPIC FEATURES


General Features



  • Well-circumscribed, lobulated, white-yellow, nodular mass; similar to other SCST with no unique gross features


  • Cystic areas may be seen


  • Hemorrhage and necrosis are uncommon


MICROSCOPIC PATHOLOGY


Histologic Features



  • Mixture of recognizable SCST components (Leydig cell, Sertoli cell, or granulosa cell, rarely theca cells)


  • Mixture of undifferentiated or unclassifiable epithelioid and spindle cell components


  • Epithelioid component



    • Solid or hollow tubules, irregular aggregates, or anastomosing trabeculae (SCT)


    • Round to ovoid cells with eosinophilic, amphophilic, or vacuolated cytoplasm and prominent nucleoli (LCT)


    • Oval round cells with nuclear grooves, Call-Exner-like bodies (GCT)


    • Mixture of above mentioned recognizable SCST


    • Unclassified epithelioid cells with vesicular nuclei, occasional prominent nucleoli, rare mitotic figures


    • Signet ring cell SCST has been reported


  • Undifferentiated spindle cell component



    • Usually hypercellular spindle cells merged with fibrous stroma


    • Spindle cells may form fascicles


    • Spindle cells may have nuclear grooves


    • Cellular pleomorphism and mitotic figures are variable


    • Has been reported as a variant of granulosa cell tumor because of its immunohistochemical similarities



  • Features that are more commonly associated with malignant outcome: Invasive growth pattern, angiolymphatic invasion, nuclear atypia, mitotically active, and areas of necrosis


Predominant Pattern/Injury Type



  • Neoplastic; diffuse spindle cells, mixed epithelioid and spindle cells, or combined form of known SCSTs

Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Sex Cord Stromal Tumor, Mixed/Unclassified
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