Definition
=========================================================================

• Low grade neuroendocrine carcinoma, similar to counterpart at other sites
• Usually monomorphic cells growing in solid nests, trabeculae or pseudoglands

Terminology
=========================================================================

• Also called pure neuroendocrine carcinoma

Epidemiology
=========================================================================

• Rare (<1% of testicular neoplasms), mean age 46 years

Etiology
=========================================================================

• Carcinoid tumors are neuroendocrine tumors derived from enterochromaffin (Kulchitsky) cells that secrete serotonin, and most commonly arise in GI and respiratory tracts
• In testis, presumed to be a monodermal teratoma, although 20% have other teratomatous elements

Clinical features
=========================================================================

• Only 10% have clinical carcinoid syndrome

Prognostic factors
=========================================================================

• Metastatic disease is associated with carcinoid syndrome, tumor size 7 cm or more (Cancer 1993;72:1726)

Case reports
=========================================================================

• 12 year old boy with nodal metastases (J Pediatr Surg 2005;40:e19)
• 25 year old man with intratubular germ cell neoplasia in surrounding tissue (J Clin Pathol 2005;58:1331)
• 41 year old man with incidental tumor found at elective sterilization (J Androl 2004;25:338)
• 76 year old man with metastatic carcinoid tumor (Arch Pathol Lab Med 1981;105:515)

Treatment
=========================================================================

• Excision; occasionally metastasizes

Gross description
=========================================================================

• Solid, yellow-tan, well circumscribed
• Cysts reflect other teratomatous elements

Gross images
=========================================================================

Solid, tan cut surface

Micro description
=========================================================================

• Islands of cells forming small acini; cords forming rosettes or sheets
• Cells have granular eosinophilic cytoplasm, round nuclei with granular chromatin
• Usually no intratubular germ cell neoplasia, no/minimal mitotic activity, usually minimal atypia or necrosis

Micro images
=========================================================================

Islands of tumor cells in lower right

Tumor cells have eosinophilic cytoplasm and salt and pepper chromatin

Well defined acini and solid islands of cells separated by fibrous stroma

Eosinophilic cytoplasm and round nuclei with coarsely granular chromatin

Organoid pattern with minimal atypia

Insular pattern, chromogranin+

Intratubular germ cell neoplasia

Placental-like alkaline phosphatase and OCT4

Various images

Cytology description
=========================================================================

• Isolated or sheets of tumor cells with granular cytoplasm, round nuclei, uniformly distributed fine chromatin

Positive stains
=========================================================================

• Cytokeratin, chromogranin, synaptophysin, serotonin (Am J Clin Pathol 2003;120:182)

Negative stains
=========================================================================

• OCT4, CD30, c-kit, TTF1 and CDX2

Electron microscopy description
=========================================================================

• Neurosecretory granules

Molecular / cytogenetics description
=========================================================================

• i(12p) (Clin Cancer Res 2008;14:1393)

Differential diagnosis
=========================================================================

• Metastatic carcinoid to testis: usually bilateral, multifocal, vascular invasion, case report of metastasis to scrotum at Am J Clin Pathol 1991;96:664
• Sertoli cell tumor: lacks prominent cytoplasmic granularity and coarse chromatin; inhibin+

This information is intended for physicians and related personnel, who understand that medical information is often imperfect, and must be interpreted in the context of a patient's clinical data using reasonable medical judgment. This website should not be used as a substitute for the advice of a licensed physician.

All information on this website is protected by copyright of PathologyOutlines.com, Inc. Information from third parties may also be protected by copyright. Please contact us at copyrightPathOut@gmail.com with any questions (click here for other contact information).