Adenomatoid Tumor



Adenomatoid Tumor


Steven S. Shen, MD, PhD

Jae Y. Ro, MD, PhD










Adenomatoid tumor, the most common adnexal tumor, presents as a well-demarcated white-tan firm mass image in the epididymis. It lacks hemorrhage, necrosis, or gross infiltrative characteristics.






Adenomatoid tumor is composed of gland-like spaces lined by flattened cells. A few isolated cells with cytoplasmic vacuoles mimic signet ring cells image. A variety of patterns are usually present.


TERMINOLOGY


Definitions



  • Benign paratesticular tumor of mesothelial cell origin, which has a variety of growth patterns, including glands, cysts, tubules, cords, or isolated cells


CLINICAL ISSUES


Epidemiology



  • Incidence



    • Most common tumor of testicular adnexa


  • Age



    • Range: 18-79 years (average: 36 years)


Presentation



  • Usually asymptomatic, small and solid intrascrotal mass


  • Most commonly occurs in head of epididymis, although it may occur in tunica vaginalis, albuginea, and rete testis


  • Tumors may rarely be intratesticular and involve parietal tunica or spermatic cord


Treatment



  • Surgical approaches



    • Surgical excision is curative


Prognosis



  • Benign clinical course


MACROSCOPIC FEATURES


General Features



  • Small, well-circumscribed, white-tan, homogeneous, firm mass


  • No hemorrhage or necrosis


Size



  • < 5 cm (majority < 2 cm)


MICROSCOPIC PATHOLOGY


Histologic Features



  • Well-circumscribed, unencapsulated mass


  • Tubules; gland-like, irregular cystic spaces or channels


  • Nests and cords; true solid pattern rare


  • Cuboidal, flat, or ovoid cells with round nuclei and abundant dense cytoplasm with vacuoles


  • May show signet ring cell appearance


  • May be cellular or infarcted


  • Intervening fibrous stroma ± smooth muscle fibers


  • Lymphoid aggregates may be prominent within or at periphery of tumor


  • Rare tumors may be infarcted



    • Surrounding inflammation and reactive myofibroblastic proliferation may simulate invasion


Cytologic Features



  • Eosinophilic, vacuolated, signet ring


Predominant Pattern/Injury Type



  • Nests, cords, gland-like, tubular, cystic, and plexiform


Predominant Cell/Compartment Type



  • Cuboidal to flat to ovoid with uniform cytology


ANCILLARY TESTS


Histochemistry



  • PAS-diastase



    • Reactivity: Negative


  • Mucicarmine



    • Reactivity: Negative



Immunohistochemistry



  • Positive for cytokeratin, calretinin, Podoplanin(D2-40), CK5/6, thrombomodulin, WT1


  • Negative for CEA, CD15, MOC-31, EpCAM/BER-EP4/CD326, FXVIIIAg, S100, CD31, CD34, FLI-1


DIFFERENTIAL DIAGNOSIS


Sex Cord Stromal Tumor



  • Usually intraparenchymal tumor


  • Positive for inhibin and Melan-A(MART-1)


  • Negative for cytokeratin


Malignant Mesothelioma



  • Larger tumor, destructive and infiltrative growth


  • Greater cytologic atypia


Metastatic Signet Ring Cell Carcinoma



  • Clinical history and older age


  • Infiltrative growth, greater cytologic atypia, frequent mitoses


  • Positive for CEA, CD15, EpCAM/BER-EP4/CD326, and MOC-31; negative for calretinin and Podoplanin(D2-40)


Epithelioid Hemangioma/Hemangioendothelioma



  • Vasoformative lesion composed of vacuolated cells


  • Positive for vascular markers (CD31, CD34, FLI-1); negative or weakly/focally positive for cytokeratin


Germ Cell Tumors (Particularly Yolk Sac Tumor)



  • Intraparenchymal mass with heterogeneous appearance


  • Obvious malignant cytologic features


  • Positive for Oct3/4, SALL4, and CD30(BerH2); negative for calretinin


Leiomyosarcoma or Leiomyoma (vs. Leiomyomatous Adenomatoid Tumor)

Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Adenomatoid Tumor
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