Table of Contents
Definition / general | Essential features | Terminology | Epidemiology | Sites | Pathophysiology | Clinical features | Diagnosis | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Positive stains | Negative stains | Differential diagnosis | Board review style question #1 | Board review style answer #1 | Board review style question #2 | Board review style answer #2Cite this page: Dall C, Zynger D. Teratoma with somatic type malignancy. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/testisteratocarcinoma.html. Accessed January 18th, 2021.
Definition / general
- Testicular germ cell tumor with somatic malignancy arising from germ cell tumor progenitor cells that occupies ≥ 1 microscopic field using 4x objective
Essential features
- Commonly metastatic at diagnosis (Eur J Radiol 2009;69:230)
- Rhabdomyosarcoma most prevalent somatic type malignancy (J Urol 2016;196:95)
- Must be distinguished from sarcomatoid yolk sac tumors which represent up to 60% of post chemotherapy sarcomatous tumors (Am J Surg Pathol 2015;39:251)
Terminology
- Previously termed teratoma with malignant transformation and teratoma with somatic malignancy
Epidemiology
- 3 - 6% of testicular germ cell tumors with teratomatous components (Cancer 1985;56:860, Cancer 1984;54:1824, J Urol 1994;152:1144)
- Median age of diagnosis in late 20s, similar to teratoma (Cancer 1985;56:860, Cancer 1984;54:1824)
Sites
- 90% with gonadal primary but primary tumor may be found in the mediastinum or retroperitoneum (J Urol 2016;196:95)
Pathophysiology
- Two proposed origins of somatic malignancy (Eur Urol 2007;51:1306):
- Mature teratoma
- Embryonal carcinoma
- Somatic malignancies generally have same genetic aberrancies as germ cell tumor (Am J Surg Pathol 2012;36:1849)
- Isochromosome 12p seen in many cases (J Urol 1998;159:133)
Clinical features
- Somatic malignancies more commonly found as relapse, rather than at initial diagnosis (J Urol 2014;192:1403)
- Timing of relapse varies based on type of somatic malignancy (J Urol 2014;192:1403)
- Carcinomas diagnosed later than sarcomas
- Scarce data regarding differences in presentation of somatic type malignancy and germ cell tumors
Diagnosis
- Found as metastatic disease, within the testis or both (J Urol 1998;159:133)
- Histologic features and immunohistochemistry determine somatic malignancy subtype
Radiology description
- Imaging may suggest specific somatic malignancy in germ cell tumors (Eur J Radiol 2009;69:230)
- Ossified lymph nodes and soft tissue reported in osteosarcoma
- Peritoneal carcinoma seen in adenocarcinoma
- Septal thickening and opacifications reported in a case of bronchoalveolar carcinoma
Radiology images
Prognostic factors
- Poorer prognoses compared with those without malignant transformation due to higher likelihood of metastatic disease at presentation (J Urol 1998;159:859, J Urol 2016;196:95, Am J Surg Pathol 2007;31:1356)
- Traditional International Germ Cell Cancer Collaborative Group (IGCCCG) prognostic factors may be less significant (J Urol 2014;192:1403)
- Disease confined to the primary site generally has favorable prognosis
- Sarcomatous components portend a worse prognosis (Am J Surg Pathol 2007;31:1356)
Case reports
- 28 year old man with late recurrence of teratoma with 2 somatic type malignancies (Int J Dev Biol 2013;57:153)
- 35 year old man with intracranial somatic malignancy (Rom J Morphol Embryol 2016;57:1389)
Treatment
- Surgical resection mainstay of treatment
- Chemotherapy based on histologic subtype of malignant transformation (J Clin Oncol 2003;21:4285)
- Less responsive to cisplatin based therapy (J Urol 2014;192:1403)
- Radical surgery often utilized for advanced disease (J Urol 1998;159:133)
Gross images
Microscopic (histologic) description
- Atypical mesenchymal or epithelial cells occupying ≥ 1 low power field (4x objective, 5 mm in diameter) (IARC: WHO Classification of Tumours of the Urinary System and Male Genital Organs, 4th Edition, 2016)
- May have infiltrative or expansive histology
- Somatic type malignancies differ in prevalence (IARC: WHO Classification of Tumours of the Urinary System and Male Genital Organs, 4th Edition, 2016, J Urol 1998;159:859)
- Sarcoma most common (63%) with rhabdomyosarcoma (35%) and sarcoma, not otherwise specified (24%), comprising the majority of cases
- Adenocarcinoma makes up an additional 22% of cases
- Primitive neuroectodermal tumor and squamous cell carcinomas next most frequent
Microscopic (histologic) images
Positive stains
- Desmin, myogenin, vimentin depending on type of sarcoma
- Cytokeratin, epithelial membrane antigen if carcinoma (Virchows Arch 2012;461:27)
Negative stains
Differential diagnosis
- Choriocarcinoma: cytotrophoblasts mimic squamous cell carcinoma but express β-hCG
- Metastasis of non germ cell tumor: primary sarcoma or carcinoma
- Teratoma without somatic type malignancy: malignant appearing somatic cells do not occupy ≥ 1 low power field at 4x magnification
- Yolk sac tumor (glandular or sarcomatoid): positive for GPC3, keratin and AFP (Am J Surg Pathol 2014;38:1396, Am J Surg Pathol 2015;39:251)
Board review style question #1
Board review style answer #1
Board review style question #2
- Which genetic feature would be most commonly found in teratoma with somatic type malignancy?
- Isochromosome 12p
- MYC amplification
- TERT promoter mutation
- Upregulation of ERG
Board review style answer #2